1500 Merc

[59powercat1400]

alright you guys, I just bought a 1500 Merc from a guy on this board. why is it that you guys blasted me for running a Chrysler and this * runs 6mph slower? I think some of you guys are talkin out of turn. lets hear it what am I doing wrong. it can't be the motor right? it MUST be me.

[59powercat1400]

pic

[59powercat1400]

*

[59powercat1400]

I've never been more dissapointed with any motor I've ever bought.

[59powercat1400]

I'll never believe another word you guys have to say.

[77STREAM]

would be a nice replacement for my tired 1500!

[Mark75H]

Dick, there can be a lot wrong with the motor and still push the boat down the river.

What rpm are you running? What pitch on the prop?

What is the compression on a compression test? Where is the timing set? Any evidence of water on the spark plugs?

[Bruster]

You bolted the motor on your boat, it ran 6 MPH slower, and we don't know what WE are doing?:eek: :confused:


Originally posted by 59powercat1400
I'll never believe another word you guys have to say.

[Dave S]

Well everone knows that ya need a Raceman tunna to make that old motor go.:D HeeHee.;) Musta been one of T Rexs chisslers ya replaced.:eek: Really you have a long shaft on a old boat that probaily needs a shortshaft. I see ya got it jacked up but is it high enugff?? Keep on trying. Want to sell that no good slow chissler.:rolleyes:

[dale robertson]

Dick,
Take Mark-75's advice and check the basic's first. It really doesn't matter to the boat what brand of engine is on the transom as long as it is making its rated horsepower, has the right prop for the application and is mounted at the right height.

How long has it been sitting? Could the carbs be a little gummy from stale gas? Might not hurt to take the jet's out and see. When you have the plugs out check for any metal deposit's and rotate each piston up to T.D.C. and take a look at the top of the deflector on the pistons and make sure they all look good( no bad signs of detonation damage). How is the idle? Is it running on all six? Are all three carb's synched and going to W.O.T ? What's the gear oil look like?

Try some other props once you know everything else is right.
I have a Record 4 blade nibral cleaver that has been sitting in my garage for about 30yrs that you can have if you want it (free). Im tired of looking at it. I think it's a 14X26 but not sure. Not the best prop in the world by modern day standards but I don't know what you have now.

Anyway, hope this helps
Dale

[59powercat1400]

it's not that I don't like it Bruce, but the motor just isn't as powerful as I was led to believe. It will never spin the size prop that some of these guys said it would. I expected it to blow off my Chrysler and am just a little disappointed. I know I need a short tower and a better prop, I'll get right on that. when I got it the guy wanted to sell me a 30" chopper, but it'll probably end up in the 24" range. how many rpm can this thing handle? thanks, Dick.

[59powercat1400]

thanks for the offer Dale. I may take you up on it if I can get the motor to spin a 26. the motor was running when I picked it up from what I understand so it hasn't been sitting around for a long time. the guy even ran it for me and it has good compression. Dick.

[dale robertson]

I wouldn't worry about going to the 15" exhaust housing untill you get it sorted out as long as you can get the mounting height where you need it with your jack plate. Just curios, What were you getting out of it with the Chrysler?

[59powercat1400]

it would run 65 all day long with a best of 68 with me in it(an old, bald, fat guy). the transom height is 25 inches with the plate and I think it needs to go higher.

[Raceman]

Since I don't know anything about the dynamics of a Powercat it's hard to offer setup advice, but my 1500XS is up about 3 inches on an Ally transom and it's a 15" motor. (Don't forget that there is only about 4" difference between long and shortshaft inline Mercs instead of 5" on the V6 Mercs)

If the boat doesn't need bow lift you don't need a chopper. If you can't pull a 28, it probably ain't gonna run 70's.

All of the "go through the engine basics" is sound advice. If it's off that much I'd be lookin' for a weak cyl since inlines are proned to it.

[dale robertson]

The 150 should be happy @ 5,800-6000r.pm's if I remember right.
If you are only getting 5,200 now with a 26 " two blade (What diameter ? looks kinda small in the pix) something is way off. Has the big gearcase given it a lot more stern lift and stuck the boat to the water? Looks like it had a fair amount of air under it in the movie with the Chrysler on it. How far is the propshaft below the bottom of the boat? I can't tell from the picture's .
How fast is one of those things with a pair of Scott's?

[Bruster]

1st off, There aren't to many inlines that will spin a 30" with a 2.0:1 gears, on anything more than a kitchen table.
2nd... 5200 rpm with a 26" prop fits right in the speed range you are eluding to, ~57 mph with 10% slip.
Now you know this, you can pick a propeller that will let the inline spin to 6,000+ rpm and start adjusting the setup.
The best running propellers out there right now are the Merc Trophys. Spend a few $$ on eBay and buy yourself one for Christmas.

[59powercat1400]

thanks Bruce, I'll look for a trophy. Can anyone tell me how many thousandths BTDC this thing is supposed to fire? The decal is worn off the flywheel and my fine Clymer manual is no help. I know it's supposed to be 21 degrees. Thanks, Dick.

[77STREAM]

If that prop offer isn't taken up by 59powercat1400, I would be interested in trying it on my Vector/Inline 1500 setup! Let me know!
Pete

[Raceman]

Bruce, I've seen you mention Trophys as good in high perf applications a couple of times today. Have I missed something here? I would have mentioned a Trophy for a bassboat, or something that needs a hubbed type blade, but it's kinda hard to think of em as "best running propellers out there right now" on a true high perf boat with a surfacing propeller.

[Bruster]

Originally posted by Raceman
Bruce, I've seen you mention Trophys as good in high perf applications a couple of times today. Have I missed something here? I would have mentioned a Trophy for a bassboat, or something that needs a hubbed type blade, but it's kinda hard to think of em as "best running propellers out there right now" on a true high perf boat with a surfacing propeller.

I never implied they were the best propeller out there on a true high performance boat with a surfacing propeller.
We're not talking a STV with high perfomance V-6. All of what's going on in the 2 threads that I mention the Trophys, would be used on older performance recreational boats with relitively low H.P. motors. This group of guys (me included) want to run as fast as they can, accelerate as fast as they can and have as much fun as they can, If you were to run your Ally with your 30" club, and then run a trophy you would wonder why you hadn't done this a long time ago. Again it's like bias ply tires on a new Corvette for this kind of boat.

[CrayzKirk]

Hi,


Can anyone tell me how many thousandths BTDC this thing is supposed to fire?

.101" BTDC is 21* and .124" BTDC is 23* although I probably wouldn't go above 21*.

Prop the motor to spin about 6k or it is prone to detonation.

Kirk S.

[sho305]

My 1500 is down on power at anything =< 5400. 5800 is a good spot to aim for max speed, 6K is near the same with more zip. Before I read about how you should not advance the timing on the inline here...I sat mine at 21 on the starter wot, no plugs. Later I moved it up higher then part way back to where it still had a gain. It gave a better holeshot, but I think I only got maybe 1 mph top end. Likely a good thing I was running it on a smaller lake and using premium. Since I never checked it running like you are supposed to, I don't know where it is exactly but guess maybe 23.

Mine has this 23 degree sticker on it (original '73?) I'll reset it next time I run it.

[59powercat1400]

thanks guys. I'll set it at .101 and see what happens. I'll call supreme marine and see if I can get a new decal. I'll try and get it out again on friday. maybe it won't be snowing this time. Dick.

[dale robertson]

If that prop offer isn't taken up by 59powercat1400, I would be interested in trying it on my Vector/Inline 1500 setup! Let me know!

Its yours if Dick doesn't want it.

[150aintenuff]

That OL engine definatly could run better and should run a 26-30.... but for some reason it aint... so get the basics fixed and what wver needs to be done to bring down center of gravity.


that engine doesnt like much over 6000 unless its built up alot most wont turn more than 55-5800 if your chry could turn 6-6500 It may have percieved as stronger on top but what is the Holeshot compared.... or midrange

goodluck

[sho305]

My old comp gauge shows 120-122psi. Does it have a good fuel supply? Though that usually is obvious if it does not. I also assume it is a 1400/1500 powerhead.

Otherwise you certainly will have more power when you get the rpms up if there is not anything wrong with it. I ran mine at 6400 and it went slower, about the same as it did at 5400...though the props were not the same brand. On my 930lb 17' vee it spins to 5800, then wanders to 6K after a bit with a 20p laser II, say in a half mile run.

[bridges]

59powercat1400:

I am amazed that you would blame others for the problems of a motor you bought. The GENEROUS and FREE advice that you got (and continue to get) from the guys here is related to their past experience with motors like yours.

If these guys told me that 69 Camaros were awesome, and then I went and bought one that ran like ****....whose fault would it be?

Your problem could be one of about 2 dozen things in no particular order...

1. Is it really a 1500?....decals mean nothing
2. compression/ pistons
3. timing
4. fuel
5. set up
6. lower unit gear ratio
7. prop
8. plugs
9. etc. etc. etc.

[59powercat1400]

I'm not blaming anybody. If you read the first post I was pointing to the guys that bad mouthed my running a Chrysler and that's all. I am sorry I didn't make that clearer. Dick.

[59powercat1400]

Hi Dale, I will take you up on your offer to try your prop. Just so you know I won't be able to run it again till spring, it's too cold here now and starting to freeze. Thanks, Dick.

[Mark75H]

Brrrrrrrrrrrr. :D

[bridges]

Originally posted by 59powercat1400
I'm not blaming anybody. If you read the first post I was pointing to the guys that bad mouthed my running a Chrysler and that's all. I am sorry I didn't make that clearer. Dick.

Fair enough. I re-read your post. Sorry for the tone.

You will get a lot of suggestions for making your rig run better....most of it good ;) I'd suggest searching for any problems methodically, the most simple first. For me that means serial #'s, then fuel, compression, set-up, prop, mechanical, electrical.

[MN4V]

During my brothers Sport J days 7,000 to 7,100 rpms with a 14d x 28 pitch Merc cleaver was what the top guys ran.

[dale robertson]

Hi Dale, I will take you up on your offer to try your prop. Just so you know I won't be able to run it again till spring, it's too cold here now and starting to freeze. Thanks, Dick.

She's yours, just tell me where to ship it and send me a few bucks for the fed-x after you get it. I will see if i can get the pitch checked to see what it really is. I know it worked pretty good on a 16' Checkmate with a 150 on it about 30yrs ago. It needs a little T.L.C. now, as it has been through a divorce, garage fire, lots of beer and three moves.

My email is : dale.robertson@volvo.com

[Raceman]

There are a couple of statement on RPM's with a 1500 that won't work for you if you try em, so I'm gonna attempt a little clarification:

"that engine doesnt like much over 6000 unless its built up alot most wont turn more than 55-5800".

ANY 1500 that's mechanically sound will turn more than 55 to 5800. As a matter of fact, if it's pitched to turn only 5500 at WOT it's gonna be VERY susceptible to burning pistons. Like somebody else said, 5800 to 6000 is optimum operating range at full throttle for these engines. It is true that some roundy round guys turned the engines around 7K, BUT it was done to get a good balance of acceleration off the corners without killing top end. You can bank on the fact that if those same guys were setting up to run Kilos they'd ad pitch and drop the RPM down to around 6K.

[59powercat1400]

ok thanks. 6000 is what we'll shoot for.

[150aintenuff]

True I did say 55-5800, but I will ad clarification to that as well. If memory serves those engines were built form factory for 55-6000 ( i could be wrong no manuals to varify.... somebody want to set it right im lookin for it...) there are a few that will run 7K but as i stated before MOST dont spin that fast... 6 is a good number to shoot for and IMHO probably the best.

If my memory is correct(never said it was) 5500 shouldnt burn a piston 5000 :eek:definatly could but it is a good idea to start watching for it if falls below 5500.

The only Practical experience I personally have with the 1500 Inline is on a 18' trihull fishing boat so not the fastest thing on water but it does top out at WOT at 5800 with 21P QSS 2000 prop...:o not exactlly fast but it does the job for who owns it....

I said before that 1500's dont like much over 6000 I never said that they wont run there.. or be reliable for ever either, i simply said they dont like it.....(lots of mass moving around)

I hope that takes some confusion out of it....:confused:

Aslo If that is a 1500XS I know there were a slightly different range for that engine..

[dale robertson]

Ted at Speedmaster said he used to spin the 73 stock ones at 7,000 easy and the J blocks he got almost 8 out of them
I had a "J" motor. My boat would always run faster propped @ 6,000r.p.m.'s than 6,500 r.p.m's. I heard all the claim's of people turning them 7,000 or so back then. Maybe I missed something but to me the engine just doesn't have the port timing or the carburetion to make any power up there.

[dale robertson]

I keep mine at about 5800 to maybe 6,000 absolute max. My motor stays together and these other ones mostly don't maybe that tells you something.

Go down in pitch untill you can spin 7,000 and see how fast you go.

[bearclaw]

This might be obvious and was probably mentioned before, but maybe this engine is just 'tired'. I've had three inlines (1400 and two 1500's), and one of the 1500's had this affliction. It's compression was fairly even, just low - and it performed like it. Started ok, idled ok, ran smooth, just didn't have the power.

My buddies that ran FJ back in the day shot for 6300-6500. Can't remember about the Sporty J guys. I prop mine for 6K these days as I'd like it to hold together as long as possible. ;)

[sho305]

There are some here that raced/race them, most of them say they run them 7K but they are modified. Still they say if they wanted top speed they would run less rpms...they run that way to get out of the corners. They try to get more rpm spread, but it still kills low end so they don't work well on lake boats.

My manual says 5300-5800 for 1400/1500, 5800-6300 for 1500XS. Serial on mine is on block half bolt flange, above fuel pumps...also on clamp. Hard to compare with mine pushing a hefty checkmate 17 open bow with no pad, but mine could be tired too (dah, maybe I can change the boat soon). Sure looks like original paint on bolts (& nuts on mine) and not touched. '73 is a long time ago for it to be real fresh. Gearing should show in your rpm to mph if not 2:1. I remember Capt Insane-o also saying you had to have a tight motor to get max speed with his viper, I think around 80mph.

Best I can gather reading lots of inline posts they will hold together to XS rpms ok up to ~6300, those running more get race ready service. But, for speed running you are past the power peak on a stock motor anyway so no sense in going there. Seems like it would shorten life some anyway.

Ah ha, here is one dicussing race rpms...using stock XS in part http://forums.screamandfly.com/forums/showthread.php?s=&threadid=41978&perpage=15&pagenumber=2

Powercat, have you posted about your force here? I'd like to read about it. My little 85hp makes a lot of laughs but I'm ok with 43.3gps on a 16' bayliner open bow with that little three banger & no jack. It'll help pay for something better. It seems to like to run over the 5500 max as well, but I was scared to leave it there (5800rpm) as I can't find any info about them here...and if it would grenade or not.:eek: It would be harder to sell that way...lol:)

[ssmith007]

I thought if you ran an I6 much past 6000RPM you risked enlarging the wrist pin hole in the piston. Rumor had it the XS had forged pistons so this was not an issue. Norris would you clarify this. I had a Kona with a 1500XS on it and I liked the 20 pitch turbo prop on it but it ran 6300 and my boat mech said be careful how much you run above 6K. Thanks. Smitty;)

[Raceman]

Personally I think the people who "remember" turning 1500XS's to 8K are having memory lapses. I don't think the rods will stand it, not even briefly. There was an old well known racer at Jasper several years ago who was talkin' to Todd from Augusta about gettin' the most out of the 1500 on his vintage Checkmate tunnel. He told him it didn't make it's max power until 9K. When he walked off I told him different................ REAL DIFFERENT.

The 1500XS DID NOT have a different part number piston. If there was ever a forged replacement piston for it I was never aware of it.

I had identical (as identical as any props with different pitches could be) 26, 28, & 30 pitch wheels for my old 15 Ally with the 1500XS and the fastest blade by several MPH was the 30, and this was on a boat that would only run mid 70's back then.

For the newbies that haven't seen me post this about a dozen times, I bought my first short 1500 in 74, a used 73 model. I've had countless ones since and have never been without at least one in all these years. I presently have either 12 or 13 1500XS's counting the ones in boxes, and either 4 or 5 20" 1500's. I've NEVER owned one on ANY boat that would run any faster ABOVE 6K than it would at 6K or slightly below.

[sho305]

You could be right, I've never seen that. I've read here the standard and XS are the same internals except slight porting that gives about 200+ to the powerband at the expense of low end. It seems to be the consensus you run the 1500 at (5800-6K) for good health/cooling/less detonation chances and good all around performance; that it runs the fastest at 56-5700rpm (but hotter and with less punch), and the XS just does the same at +200-300rpm more giving it another 5hp or something.

Just generalizing, but thought the rotating assembly was the same...if so 6300 might be pushing it for continuous use but 6K would not be so bad on a 1500 as the XS model was rated for more.:confused: I have read some threads about mod inlines...really it looked like what they did was lighten and balance them well and they hold out at 7K with a few other little tricks. Kind of impressive for that long crank. (that was racing, maybe dry pipes, unknown life span, and just what was said here)

More info here on XS/pistons/porting: http://forums.screamandfly.com/forums/showthread.php?s=&postid=498632#post498632

[Raceman]

I think the inlines will stay in one piece turned harder than 6K, but there's no reason to do it unless you're looking for acceleration. I'm sure a lot of racers pitched em to turn 6800 or 7K, but the point is, they're above the peak at that RPM.

I've never had anybody around me break cranks in an inline, although I've heard of it. The thing I HAVE seen is broken rods. I'd say they're the weak link in turnin' em hard.

[dale robertson]

The bass boater I sold mine to managed to break the crank. Then again he broke everything I ever sold him. I finally got to the point I wouldn't work on a bass boat. It was kinda cool though as the engine still ran on the top three cylinders. This was after a winter of testing and 1 season of F.J. That engine ran so good I never even took it apart. I bought two to get through the season and never took the second one out of the box. I think they were around $1500.00. Bought them on a 90 day note and just kept paying the interest on the note untill the enf of the season.

[T2x]

Originally posted by Raceman

I presently have either 12 or 13 1500XS's counting the ones in boxes, and either 4 or 5 20" 1500's.


Two things......... I'm basically speechless....except.

I hate you.

T2x.......................screaming into the silent darkness of RM's collection.

[Raceman]

T2X, the deal of the decade was the two 1500XS blocks, brand new in the original Merc boxes and still sealed for 200 each, or the pair for 350 that showed up for sale on the board here several years ago. I'm thinkin' Merc probably wanted a little more than that before they became NLA.:D :D I don't know if I've got enough electrical stuff to make over 5 or 6 of em run, but they don't have to crank to push and engine stand.

[Dave S]

I kinda thougth all the early L6 mercs had forged pistons,TRW s I think. I think that the newer rods are better, as they have no stress risers at the rod slot where the rod keeps the bolt from turning. The T2 ran higher rpms with the same parts, maybe thats why they had holes in the blocks.:D I used to modify them all the time, lots to be improved in them. Just general air flow.;)

[ggarland]

59Powercat:

Man, you really fired 'em up didn't ya? Don't sweat it, the guys here are as about as knowlageable a bunch as I have ever seen, better than the factory reps in most cases, and always shoot from the hip with solid advice. They speak with truth and passion, and I will back that up with 28 years as a Mercury mechanic. There is no bull**** here in this group, only good experience learned the hard way. Listen to what they have to say.... and learn.

George

[bearclaw]

Originally posted by Raceman
...but they don't have to crank to push an engine stand.

That almost brings tears to your eyes. :(

Like an old majestic lion in a little cage.

Or a Rolls-Royce Griffon being used as a fire pump.



Or Howard Stern on satellite radio

(wow - I don't know where THAT came from) :D

[77STREAM]

LOL:D

[ggarland]

There is only one way to witness an inline, and that is hot and screaming....... but Howard Stern??? Please don't sully my favourite outboard with that piece of ****.

George

[Bruster]

....an afternoon with one of the old Merc Racing Engineers I had plenty of questions. When the subject of how many RPM's an old inline will run his reply went something like this.....

"They will spin to 7,500 or 8,000 pretty easy, the problem is the life of the internal componets. Run the motor at those speeds and the life of the motor can be measured in hours, usually equal to less than the total number of fingers on one hand. Slow the motor down and the harmonics go away and componet life goes way up."

As I remember the big issue was crankshaft flex, understandable as long as it is.

I often mention I like to run my motors a little faster than reccomended, the reasons for this are to take advantage of a somewhat lower pitch propeller, which will always accelerate quicker, and still maintain the maximum top speed. I've run my XS motors countless hours @6,500 and have never had any issues. Works for me, but to each his own.

There are several switchboxes with rev limiters built in. the XS box (-25) as I remember does not have a rev limiter in it. others are set for 5,500 and 6,000 or something like that. Thery were identified with little round red, white and yellow? stickers on the box.

[ponyboy]

hey Dic, you will get it goin faster than the ol chry. you just need the snow to wait. LOL.
to bad these guys never heard that chry run. It would shock them like it did me, I never thought about 1 goin fast....till I drove yours. Mash the gas and hold on 0 - 60+ in a blink of an eye.
I never look at 1 with the same smirk I used to.

[ponyboy]

get the popcorn an beer ready! HAHA

[Dave S]

I don't KNOW about the RPM s of the switch box. ..... Bill Fales used to us them on his Qincy looper and run 10,000 rpms. He used 24 volts on the box, I don't know if that had any thing to do wit it. I have had blocks have a crack that couldn't be stopped from spreading, I think it was a harmronic problem. Take a L6 crank, It allways goes this side up,I think it has to do wit the fireing order, but it is a fireing order..... That could be the problem with rpms that this side up comming out of the side of the block.:eek:

[Mark75H]

I have a pile of inline 6 ignition boxes ..... none have the now "legendary" stickers and none of them refuse to run my motor 7,000 rpm ..... but many of them just don't seem to have the pow and umph and easy starting I remember from the big sixes back when they were new.

I have switched to Rapair replacement boxes which do not have rev limiters and do make the motor easier to start and idle smoother.

I think the Merc boxes have had a little time for some of the internals to go weak .... value changes to some of the transistors and capacitors and they just don't work like new ..... even when they work.



Draw back of the Rapair module: no output for Merc tach

[Dave S]

Come'on Sam Just put the fingers in the wire boots and let me crank the motor.:D HeeHee:cool:

[Mark75H]

Then my hair would look like yours ....:eek:

[sho305]

Mine ran 6400 with a 19SS and about 6mph less than the 20 laser@6K, on the speedo (that 19 was strange). Have no idea if the box is original, the terminals are all covered with that sealer but who knows. It fires instantly warm, will idle at 900 in gear but likes to kill when you shift. When I had a bad rectifier the battery would die and it would start to cut out at high throttle after about 8 gallons, I'd come in and the starter would not turn it. It would toss a 1/2" spark near all of the time when I tested it, pretty mean spark.:cool: Thunderbolt! I love those cool old names.

[dale robertson]

The thing that would help Dick the most at this point is knowing whether his engine is making close to 150 H.P. so he can go on with life and know he isn't trying to prop a sick motor. So my thoughts on this are he needs a test (load) prop. Anybody got an ole test prop for a 150? or know how to make one that will let the motor go to rated R.P.M . He could just back it down the ramp and test it on the trailer.

[sho305]

Dale, that is a good way to set the timing is about all. You can do it with a normal prop by letting it cavitate on the trailer, just make sure you are getting water pressure. I don't recall anyone posting a dyno number for an inline, but I know they (1400/1500) were all near 115 prop hp the later inline was re-rated at. Still about the lightest ~115hp out there. Anyway many here can tell us close to what speed/rpm/prop it should run given the boat design and weight, and for sure it isn't going to do well at 5200rpm. Even if it is tired but running well, that should hurt acceleration more than top speed.

[dale robertson]

Dale, that is a good way to set the timing is about all.

A test prop is normally used when tank testing an outboard motor. It is designed to load the engine so it turns rated r.p.m in the tank @W.F.O. These are the funny looking props you see hanging on the walls in most outboard shops. Some guy's that race have made homemade ones by cutting the blades down on a normal prop so they can do a sanity check on their engine before a race or testing. If you know your engine will turn it X r.p.m. when its in good shape, its a good way tell when the power starts to fall off.

[Jeff_G]

Let me give you all the real skinny on inline rpm.
In the old JP days a good running boat did around 6200 to 6500 rpm depending on prop. With smaller props like 24 or 26 they did a few more.
My motors all turn 6840 to 7000 all day.
When you look at the peak torque and HP they happen at two very different times. You need decent torque earlier to get things going and to spin up faster for acceleration. You need less torque and less HP once on plane and running right. The more RPM once at speed the more speed and the less hp needed to increase or sustain that speed. There is a finite limit on this though, nostly it has to do with the efficiency of the prop and set up. Just because one can get more RPM does not mean it is faster. I have a 26 that will turn 7600 rpm but is slower than a prop that is the same pitch and diameter that turns 6900. There is also a peak effeciency of the hull, once past that then the boat will either not increase speed, lose effeciency, or become unmanageable.
To run a circle race a 26 is about right today. A very small course a 24. If one were to run a kilo a 28/30 or greater would be needed and to keep the rpm up, the motor goes up.
The inlines today will not sustain high RPM today because, 1. they are getting old and worn and 2. the lack of proper clearances to the rotating assembly. The biggest problem is the bearing surface of the reed cages, and unbalanced cranks. BTW I run a lightweight flywheel which helps alot.
The inline pistons were never forged. They were always cast.
Although the XS motor had a different switchbox I have yet to even see a difference, none of them were ever limited.
The biggest problem I am having is cooling and fuel quality.

As for the original post, you will catch more flies with honey than vinegar! It does appear than something is off on the boat or motor set up or the motor has a problem. A motor can have good compression and even good leakdown and be so worn to be an absolute dog. I would recommend that if you plan on keeping the motor any length of time have someone competent rebuild the powerhead, and this is very important... do not let anyone under 40 or 45 touch your motor.
Cheers

[dale robertson]

Well said Jeff.

[dale robertson]

My motors all turn 6840 to 7000 all day.

What mod's are you doing to your engine's?
Are you going to stick with the inline six or go to a bigger boat and motor?

[bridges]

JeffG you are mistaken that inline pistons were never forged.

[Jeff_G]

Over the years there have been rumors to the effect that they had forged pistons but I have had just about every 150 and 150XS and they never had a forged piston. In fact I don't remember any direct charge inline with forged. Some of the old x-flow inline motors did and maybe some of the earliest twister motors. But 150 or 150xs or later, nope.
I have never seen a parts bulletin from Mercury nor any part supersuccession that would indicate a forged OEM piston. I also have copies of the APBA Inspectors Tech sheets and they would indicate forged as well, they don't.
That is one of the big problems putting a Weisco in an inline, the clearances of the forged causes problems.
I would like to see direct proof of a forged direct charged inline piston.

[Jeff_G]

Originally posted by dale robertson
What mod's are you doing to your engine's?
Are you going to stick with the inline six or go to a bigger boat and motor?

If you mean Formula V no I will stick with the set up I have. I don't believe that the bigger boats belong in the class, I believe it is a safety issue. The class was designed and created for the 13-15' boats, not 20' boats. I'll just leave it at that.

As for modifications, well lets just say there are a few. But anyone will tell you the secret to racing is a good setup, and great props. The motor is not the primary deal.

[ssmith007]

I'd just like to make clear that I have no knowlege of L6 pistons or any other pistons for that matter. The forged piston L6 comment was during a conversation I overheard. My friend/mechanic who used to work for mercury said he doubted it but the other fella had heard about it. He was probably confused between a L6 and a V6.
P.S. I wouldn't know an outboard piston from a car motor piston. Thanks. Smitty

[Raceman]

"I wouldn't know an outboard piston from a car motor piston."

You have to get an adapter plate to run a car piston in an outboard.

[ssmith007]

Norris, I am sheepishly admitting my ignorance about the pistons used in any outboard. It's nice to have experts like yourself we can rely on to set the record straight. Now I've got this hairbrained Idea I want to rebuild an L6 for a winter project. Man is my wife gonna be mad (LOL). You'd think she'd be used to it. Thanks. Smitty:D

[T2x]

Originally posted by Raceman
T2X, the deal of the decade was the two 1500XS blocks, brand new in the original Merc boxes and still sealed for 200 each, or the pair for 350 that showed up for sale on the board here several years ago. I'm thinkin' Merc probably wanted a little more than that before they became NLA.:D :D I don't know if I've got enough electrical stuff to make over 5 or 6 of em run, but they don't have to crank to push and engine stand.

Dateline---- Lost Engine, Georgia 12/1/04

A resident was found today in his warehouse. Known only as Raceman, the victim was found bolted to an engine stand fully embalmed with a sign around his neck reading "I'll stay around longer this way."...There were also various signs instructing visitors to leave all refreshments outside...... and not to touch the unique red striped shirt on the corpse.

A phone call to race boat curmudgeon, T2x, yielded the following advice. "Put a pull cord around his neck, a spark plug in his mouth, plug a fuel line in any convenient aperture, and see if he has ignition."

T2x............ wringing his hands in rage....;)

[sho305]

Thanks for the comments Jeff.

Dale, I guess under those controlled conditions a test prop would give you an idea of what you have, though no hp just comparison. I was thinking of him in the lake with one and didn't mean to sound course about it if I did. Sure if a local dealer had one tuned for an inline, that might tell something.

ssmith, I wonder if there is a pic of an inline piston on here somewhere...it is a strange critter with that big dam on top. Yeah I am thinking about freshening mine too, not sure if I should start a thread on it or not yet...asking how talented you need to be, tools, parts, etc., the low down.

[Jeff_G]

Sho, ring compressors are the biggest challenge, followed by a flywheel puller. You may be able to borow some or have a Merc dealer drop the pistons in for you. All 6 pistons and the crank go in at the same time.

Other than that there are a number of "tricks" and things to look for when rebuilding. Other than that is is a pretty straight forward rebuild, particularly if you have any prior experience. You can call me at 843 844-8739 days if you need any advice. Just remember it is free advice.:D

It does take quite a bit longer to rebuild than a v-6 Merc, but that's because it has a thousand bolts!
Good luck

[Jeff_G]

T2X, you don't need to check for spark on RM. His stuff is only for collecting and hoarding. Nothing actually gets to run or put together. :D :D

[sho305]

I been into lots of lawn equipment 2/4 stroke, auto engines, sleds, dirt bikes, but not an OB yet:) All I know is to check the reed cages for sealing to the crank, and don't screw up the bearings. Are the ring compressors special or do you mean you need 6 at once? I read my manual here a while ago, didn't look impossible but maybe a long first-timer to do. I just want it to run strong, not going to mod much if any...unless someone like you recommends this or that...;) that certainly would be great to have some info/help on it.

Been wanting to tear into it, but have it stored in 1 piece so I don't misplace anything before I do it. Most seem to say you don't need to bore them, that would be nice.

[Jeff_G]

It is do-able, if you take your time. Call me I'll give ya the whole rundown.

[Mark75H]

Sho, you do them all at once. I've had a few that once I got it all pointed right, it actually fell together ..... all 6 went in in under one second. I prefer a little more control, but sometimes it ooopses together.

[ggarland]

Ring compressors! Real men don't need no stinkin' ring compressors! Ca MON!

Actually it can be done without them if you have a good friend to help and some nerve. Get someone with steady arms and a sense of humor to hold the crank over the block while you ease the pistons in by compressing the rings with your fingers. The trick is to get the rods STRAIGHT with the bores that you are fitting, and make sure the ring locating pins are lined up. Use lotsa oil and listen/feel for binding as you ease them in. Smile. Make jokes. With a little work they will slip right in and then it is high fives all around. Sure you can pay a dealer to do it but what fun would that be ???:p

George

[dale robertson]

Only a sick mind would design an engine like this.

[Raceman]

I tried it one time without ring compressors and broke a ring. I've got several sets of em now.

Sho, the ring compressors ARE special tools. They go around the crank and squeeze the rings from the bottom. They're like clamps with 2 long fingers. Thats a real poor description, but I can't think of a good way to describe em. There are some that are dead straight, and some with an offset for the cyls that don't have the rods straight at the piston on assembly. You put the whole set on at once and slide em all in together.

[Dave S]

I will tell ya a real good way of getting the crank in. This is for real. I used to get 2 guys, one at each end to help me. Drunks are of no help. Lower the crank slowly and use ya fingers to push in the rings. The last piston ring brecks and ya cuss and try to get that piston out far enugh as to replace the broken ring........... Forget the 2 strong guys, let them get drunk....... Drill six holes in your work bench, stand the block up in those holes. Balance the crank, put the top piston in first then the rest are easy as that one helps you balance the crank. It goes nice and easy. Then drive your drunk friends for more beer. The motors with new style rods are easy, you put them all in the block and then the crank. Not sure of the forged pistons, I just assumed they were.:o

[Dave S]

I just couldn't go to sleep thinking of cast pistons in old mercs.:eek: So I went out in the shop and looked at some old Merc brochures and found in a 1976 where they tell the weigth and hp and all that BS , well there it is. 20HP and up forged pistons, just like when carl was in power in the old days. One of the things he like were forged pistons and bearings all over in his motors. He liked Forged swivel and clamp brackets also, not like the newer jap motors. They have cast brackets, but they get away with it because they are sneeky.:p HeeHee..... The newer Mercs,1986 or so have cast ART pistons. If you EVER want to cut some hard stuff try your saw on a forged Merc swivel bracket. Or do I just have my blades in backwards.;)

[CrayzKirk]

Hi,

Just to let you know that with the compressors, it is probably the easiest way to drop the crankshaft in. The first couple of times is a bit tricky however once you get used to it, it is almost scary how easy it becomes. I've thought about putting the pistons in and dropping the crankshaft afterwards and all I can think of is dropping a greasy crankpin bearing and have it get lost inside the motor somewhere.

Sets of compressors and the flywheel tool end up on eBay all the time. I made my local Merc dealer some money by ordering tools from him. Now I know the owner by name and he lets me rummage through his warehouse of used parts and name prices. Money well spent, I believe.

Lots of help from the guys here and the inline board as well. I don't have any training, just an interest in things mechanical, electrical and computer oriented.

Now, if I could just get the gremlins outta my 1350...

Kirk S.

[sho305]

Thanks for the great insight, should be do-able for sure. I'll have to ask where everyone gets the parts when I get closer. Most small motors I just slip the rings in by hand, but I see what you mean with 6 at once. I do have an old dealer here that might have stuff, they have a lot of old motor parts in back.

Kirk, that thing still is not right?

[CrayzKirk]

Of course not...

It's jinxed or I am!

Was winterizing it and when I went to put #2 plug back in, it didn't feel right; wouldn't tighten down by hand until seated. I tightened it up a little and felt it slip. Half the threads came out with the plug. Come to think of it, #1 & #2 have always felt a bit "funny" if ya know what I mean.

It ran right for one weekend; was just purring along at 5700 rpm with just me or 5500 loaded and now the carbs are leaking along with the stripped plug.

What fun. Trying to decide if I should fix the spark plug w/o disassembling the motor. Grease the tap up really well and flush the cylinder afterwards should do the trick...

More reasons to put the rebuilt 1500 or 140 ADI w/trim on the boat and sell the 1350.

Kirk S.

P.S. kinda got off track, there...

[77STREAM]

"That is one of the big problems putting a Weisco in an inline, the clearances of the forged causes problems".

I'm glad you mentioned that BEFORE I used 6 Weisco pistons in my Inline! What are the clearance problems your speaking of? How could those problems be corrected? Thanks

Pete

[Bruster]

Originally posted by 77STREAM
"That is one of the big problems putting a Weisco in an inline, the clearances of the forged causes problems".

I'm glad you mentioned that BEFORE I used 6 Weisco pistons in my Inline! What are the clearance problems your speaking of? How could those problems be corrected? Thanks

Pete

It's really pretty easy, you follow the instructions in the box with the pistons. Weisco tells you what size the bore should be. Make it that size and they run fine. Assume "you" know more than the Weisco engineers and set the clearance to what you think it should be and you are asking for trouble. I have run the Weiscos for countless hours @ 6,500 in my XS.:D :D

[59powercat1400]

does anyone have a short driveshaft for a 1977 1500 they will sell? I have a short tower on the way. thanks, Dick.

[77STREAM]

Bruce, thats good to know! I used to run Weisco pistons in all my dirtbikes, YZ's, RM's as a kid and never had any problems with them! I can only imagine they have been improved upon with the times since then! Thanks again,
Pete

[ggarland]

Bruce:

I could not agree more about the use of Wiesco pistons. As long as the clearances are set up right then there are no, and I repeat no, issues with them at all. This has been a sore spot and a source of many an argument for me in the past, I feel vindicated.


George

[77STREAM]

Are you the Inline man for the Spathe's at Hydrostream Canada?

Pete

[Bruster]

Originally posted by 59powercat1400
does anyone have a short driveshaft for a 1977 1500 they will sell? I have a short tower on the way. thanks, Dick.

Cut it, pin it (on a lathe) and TIG weld it. Never a problem if your welder is any good.;)

[Bruster]

Originally posted by ggarland


George, You know I almost ALWAYS agree with you!

[ggarland]

Hi Pete:

No, you must be thinking of someone else. But I have been making a living working on Mercs since 1974 so I know a little about them. Your 'Stream is the ultimate boat for an inline in my opinion, they are as right together as Fred and Ginger. So how about a few pictures to post??? Cheers.


George

[77STREAM]

Check out my thread in the fiberglass forum "Thr Resto". My Vector is currently undergoing a full restoration at Hydrostream Canada, and there is some pics posted of the beginning stages. I will continue to update as available! Heres one till then,

Pete

[Jeff_G]

77STREAM,
this has been debated for ages but here is a brief synopsis.
A cast piston has the grains of the metal in a random pattern. The cast piston expands evenly. The stock Mercury clearances are designed for a cast piston. The clearances in a motor with cast pistons are tighter than with a forged piston.
A forged piston expands with the grains of the metal and since the grains are "lined up", the piston expands differently. Because this created an interference problem Weisco came out (later), with boring instructions that called for a looser fit.
This some will say causes some piston slap at cold running temps. You also have to really baby the motor on breakin. The motor was designed for a cast piston.
The forged pistons also run marginally hotter, with the high thermal properties of this motor already this in itself can cause problems. The motor is already thermally on the edge so why push it.
The reason Weisco make the forged piston for the motor is simply they do not make cast pistons.
If you bore a motor for a forged piston you must go back to a forged piston on replacement.
This is not a motorcycle, automobile, snowmobile or anything but a outboard motor designed for a cast piston.
I personally would never run a forged piston in an inline. I do not have any problems with using forged pistons where applicable.
I also do not try to reinvent the wheel.
That's my opinion and take it for what you want.

[sho305]

Well, if someone is looking for 1500 Merc info, I guess they will find it on this thread:)

Kirk, I would think if you were careful a greased tap should work ok...I've done it confidently before but I guess there is a risk. My force has a head, but all three are helicoiled and seep. I have always been super careful with the inline plugs...don't even put them in real tight. I think a couple drip a little sometimes.

As long as you are talking about the forged pistons...do you need a special machine/dealer to bore the blocks? I have all my stuff done at a local speed shop, he does auto stuff but has no problem with normal 2 stroke jugs.

What can someone look forward to for guess-timated rebuild costs for no boring and with boring/new pistons?(if one only paid for machine work) Do oversize give any hp? Shut me up if you need to...:) :o

[bearclaw]

Originally posted by sho305
Well, if someone is looking for 1500 Merc info, I guess they will find it on this thread:)

It's another example of what makes this site wonderful ;)

[77STREAM]

Jeff, I appreciate the explaination. So in summary, if I use cast pistons break-in time should be theroretically reduced, vs. using a Wiseco forged piston? How about after break-in has completed? If I do decide to go with the Weisco pistons is there anything else that could potentially be an issue? Should "Warm up time" be increased on a regular basis when using the Wiseco's? It seems as though the forged pistons would last longer then the cast, what do you think? The only issue I am having with the Mercury pistons are the price! Sorry for all the questions Jeff, I just want to be sure to weigh all the options carefully before deciding!

Thanks,
Pete

[bridges]

Originally posted by Jeff_G
Over the years there have been rumors to the effect that they had forged pistons but I have had just about every 150 and 150XS and they never had a forged piston. In fact I don't remember any direct charge inline with forged. Some of the old x-flow inline motors did and maybe some of the earliest twister motors. But 150 or 150xs or later, nope.
I have never seen a parts bulletin from Mercury nor any part supersuccession that would indicate a forged OEM piston. I also have copies of the APBA Inspectors Tech sheets and they would indicate forged as well, they don't.
That is one of the big problems putting a Weisco in an inline, the clearances of the forged causes problems.
I would like to see direct proof of a forged direct charged inline piston.



Here is your proof in the following photos. This photo shows the underside of a forged Mercury 3-ring high deflector (direct charge) inline six piston. The forging numbers are visible. This is not a Wiseco piston. It is a Mercury piston and the forging numbers are the same as on the low-deflector type.

[bridges]

this photo shows a later model cast 1500 piston:

[bridges]

Since the page changed, here is the forged again for comparison:

[bridges]

Here are both pistons side by side... cast on the left, forged on the right:

[ggarland]

Hey Jeff:

What kept ya? LOL


George

[Bruster]

Good info, Bridges ;)

[ggarland]

Bridges:

I will second that. Good work, me son.


George

[Raceman]

Scott, how can you determine from the pics that one is forged and the other cast?

[Mark75H]

On my monitor I can only see the difference looking in the window of the piston skirt on the image of both side by side.

Maybe a side by side view of the skirts opposite the intake window will show the grain of the cast piston and lack of grain on the inside of the forged piston on more monitors

[bridges]

Originally posted by Raceman
Scott, how can you determine from the pics that one is forged and the other cast?

Because I took the pictures of those pistons just this afternoon! :D You can see the slickness on the inside of the forged piston, and the roughness in the cast piston. The forged piston also has a markedly thinner skirt and a different shape around the port. There is also a difference in the wrist pin bosses on these two pistons, but that's not necessarily an indicator.

[sho305]

:confused: Ok, now what motor has the.... :D this should be good for a few more pages of posts...lol

[bridges]

Here is another shot of a forged 1500 piston:

[bridges]

here is another shot of a cast 1500 piston:

note the casting seams and roughness.

[Jeff_G]

Still not convenced. Show me some documentation from Mercury as to the forged piston. I have seen some very crude castings and some very fine castings. A side by side picture doesn't show me anything. Mercury used any number of manufacturers of their slugs over the years. They used ART pistons in the 70's. I have at least 6 identical pistons with different casting numbers inside!
If you can produce documentation I will publically acknowledge I am wrong. Hey I could be! :D


As for you George you old ...... You're gloating because I didn't answer this post in the first 5 minutes? Did you maybe think I had more important things to do? Just so happens I am a new grandfather and spent most of yesterday with my new grandchild! That to me is important!

[bridges]

Originally posted by Jeff_G
Still not convenced. Show me some documentation from Mercury as to the forged piston.

JeffG, on page 26-27 of the 1976 Mercury catalog, you will find extensive engine specs for all engines made that year. On the seventh line down, there is a horizontal column entitled "pistons". In that column, you will see that all engines larger than 20 horsepower use "forged aluminum" pistons. Engines smaller than 20 HP use "cast aluminum" pistons.

I scanned the pages and since they are too large to post on this thread, I posted them in the "member gallery" section. Doing so shrunk them some, but they are still legible if you have a decent monitor. I can email them to you if you want.

[ggarland]

" As for you George you old ...... You're gloating because I didn't answer this post in the first 5 minutes? "

Ha ha ha !!! KNEW that would get a rise out of you, Gramps!!! :D :D :D

This is one subject on which you and I have locked many a horn on in the past, eh ? Remember? Lossa fun!! But I will admit that the kids come first however, gotta keep the priorites straight. That is the neat thing about Grandkids, you can give 'em back at the end of the day.......


George

[sho305]

Link to page: http://forums.screamandfly.com/Gallery/showphoto.php/photo/5002/size/big/sort/1/cat/2

Does that say 301lb for I6 w/trim, 20"?

I had a '76 850 for a while according to the serial, but it had a cowl just like my '73 not like that...no stripe just said Mercury in the center. It went faster at 6K rpm.

[CrayzKirk]

Interesting to be sure...

Can someone describe how a piston is forged? I understand the casting process; liquid metal poured into a mold, allowed to cool and mold is disassembled leaving part. Forged means what? Solid chunk of metal is heated and machined to specs?

By the way, the spark plug thread repair went well on the 1350. Greased up the tap, fished out the chips with a probe covered with grease, flushed cylinder with fuel/oil mix, turned over by hand to ensure no catches. Really seemed to like the 55* air temp and cool water temp.

I've got a couple of boxes of pistons and am curious as to how to tell the cast from the forged. Look for casting flash? Does this mean that original Merc pistons were forged and the cast ones are replacements? Or did Merc go to cast pistons later and if so, when? What about the new two semi-keystone ring pistons? Since forged expands differently than cast, how do they compare in measurement?

Kirk S.

[bridges]

Forging is the process in which metal is heated and is shaped by compressive force, usually by repetitive hammering blows using a power hammer or a press. Forging changes the "grain" structure of the base metal used. It also changes the way the metal reacts under heat and stress, which is discussed earlier in this thread.

The forged object may be machined or ground afterward.

[150aintenuff]

But i have to ask.... is that 1750 349 lbs in the broshure???:confused: if so where did mercury add weight to their V6 OB my father has a 1989 150hp (same 2.0L block) and his is 404lbs, where is the extra weight or is that just merc fuging the ##'s

if the 1750 is indead 349 lbs where could weight be reduced on the newer motors to shed the fat...i know that they added a PT/T assembly to bracked but 55lbs there cant be that much weight in that trim pump... or is there... just an observation


and SHO i do believe you are correct on the 20" I6 weight, i know they are LIGHT in comparison...

[Jeff_G]

Well, I'll be a damed ......... For years back in the 70's guys talked about getting forged pistons. Yet when ever we built motors the pistons we got were cast. This was back in the 70's. Mercury changed vendors many times with the best pistons being ART.
I'm wrong, see George I admit it.
Now that brings up a different point. I know for a fact that there is a problem using forged pistons in an inline. Maybe that is why the change to cast? Why would it take Merc at least 4 or more years to change? Something I have to look into.
Bridges, thanks for the proof.

[Mark75H]

Come on, Jeff, you know the engineers have neither the first nor final say in any production issue ... bean counters rule! Sometimes bean counters have to see dollar sign results rather than predictions form engineers before a change can be made. Sometimes it is politcal ..... maybe someone had to get divorced before they could drop the contract where their brother-in-law was the salesman :)

[sho305]

I know it is typical for a remote trim motor to not be included with the motor...I bet they did not there either, and the extra for the trim is the rams/clamp assy...not the pump. I know my pump is mounted inside the transom and it is a big heavy iron thing. Has to be all of 20lbs plus the oil/lines. Inline also has those add-on ram mounts bolted on the transom.

Of course the I6 is no 150hp, but still light compared to other ~115hp's; and the new motors just seem to add more and more weight. Sure is strange in our time of a technology boom to see things like that going backwards. 348lb for a classic 125, 375lbs for a three cylinder 115 opti.(I can understand the DI weight, but a triple? My 72ci force is 275lb w/integral trim and this opti is 92ci...+100lb???) On one thread someone said they are making the new motors more reliable and so, more weight...I thought wt*, my inline is 30 YEARS old and still going with more general performance to weight than new motors...does than mean a new one will last 40 or 50 years here in MI seasons? I might be dead by the time it blows...lol

Also remember reading in other threads that some think the 2.0 weighs more than a 2.4? Due to thicker cylinders/same block?

[150aintenuff]

sho:

Reread the first few lines I was refering to the 1750 hence the title slightly off topic, I also relized that the engines of that era had boat mounted trim pumps but they dont weigh 55lbs including ALL of their parts.... I was comparing 2.0Lv6 to 2.0L v6
I was never implying i was comparing an I6 to a V6 That 1500 I6 is a good strong 115-125hp at prop, especially XS versions and it is strange to me as well that MERC as well as others are adding USELESS and DOWNRIGHT UGLY IMO body cladding, cowlings and ect to "make em pretty" :mad: :mad:which only adds to the weight....... If only the performance comunity had more pull with them bean counters we might just get out motors back to what they were when Yahama brought out their PROV 150 and the industry CARED about power to weight ratio rather than emmissions....:D:D


I could be wrong but isnt a 1200lb boat that has a twostroke at 150 hp and gets 5mpg more efficient than a 1400lb boat with a 150hp 4stroke getting 5mpg.... less weight =speed. Speed = efficiencey Efficiency = lower emmissions, lower emmissions = CLEANER OB :D:D

example above would be say a 800lb hull with respective manufactures ob and same hull with respective manufactures 4stroke counterpart....


I may have to start a new topic.....;) ;) :

[sho305]

No I don't know why the 1750 weight is listed like that and sorry, lots of people get confused by the 1500 inlines so I tossed a reference to it in there.

I've read some of the tests, and it seems for fishing motors they(2/4stroke/DI) are somewhat close in performance...on a bigger boat! The tests do not address what happens when you try to run a 17' hull/etc. and run into the weight. Even here we are talking about 100-125hp motors, and they are heavy too. I'm sure a heavy Verado will work fine on a 20'+ hull, but adding weight to a 100-200hp motor has a much greater affect IMHO.

Emissions we will have to get around nomatter, just like cars...but we can see we CAN have our cake and eat it too with cars. One part of it seems to be wanting to use mids and LUs from motors with twice the hp. Something like DI or a 4 stroke will add weight, but the power per ci is not improving and they do not lighten the rest of the motor.

A good light hull does matter...I read here you can go amazingly fast with a 90hp on an Allison....but I don't see my hobby affording one anytime soon.

[ggarland]

“I’m wrong, see George I admit it."

Somebody pinch me, I must be dreaming!!! LOL My God, old son you are full of surprises!! Nice to see that you are not afraid to admit a mistake, that means a lot in my book. Guess I figured you all wrong, I apologize.

Anyway, just slightly off topic, but when are you going to post a picture of that grandkid you have been raving about? Gettin' impatient here pal! I got a real soft spot for kids.....


George

[150aintenuff]

sho:

"Emissions we will have to get around nomatter, just like cars...but we can see we CAN have our cake and eat it too with cars. One part of it seems to be wanting to use mids and LUs from motors with twice the hp. Something like DI or a 4 stroke will add weight, but the power per ci is not improving and they do not lighten the rest of the motor."





I totally agree... The marine industry is trying to kill the sport of powerboating.... the attempts of publications suchas this one B&wB and others have made one thing clear... we need fast light and powerfull ob in our shops and on our hulls... imean come on that 1500 while being rated at the powerhead was "light" and it was considered big at the time... i would hate to think how much it would weigh now if it were built today... 500...no 600 lbs......i dont know te only real i6 to i6 new vs old compparison we have is the piglet verado...... i dont care howmuch power it has or that it has a supercharger... its a pig... even a 21'boat would run better with a good old 1500XS or T3 even than thatpiglet could ever think of.... lets rise up as a comunity and takeover the execs at merc and build an outboard that will be around for another 20+years that is under 400lbs..... even the new optis in the 115 hange are getting to the point where they cant say that....


hummmmm how about a test.... 1500xs vs a new 115 opti... same rough prop hp.... wonder who would win technology or good ole tuners that knew how an ob was suposed to run......... fast light and first....:)

[Jeff_G]

The story goes on...
After the brochure Bridges scanned it appears some Mercs had forged pistons. So I started some digging around. I talked to one very knowledgable friend that said he thought Merc used forged just for one or two years. Possible a TRW piston. But he doesn't remember actually seeing any. He does remember a very high quality die cast that would look similar to a forged.
Another "Mercury" friend told me,
"The pistons that "Hi-Perf" sold were cast. There might have been some forged pistons around in Engineering but I don't remember that we sold any over the counter.

I don't remember the brochure stating the forged piston but gee that was 30 years ago we may have had something that stated that. I'll look at some of the old literature and if I find anything I'll let you know."

This just gets more interesting.


As for the comparison between yesterday's boats and motor and todays, you can't compare.
The boats of today would be pigs with the old inlines. The motors of today have twice the torque of the old. The transom heights are now all 20", the boats weight more, carry more, and are equiped with much more.
The emmissions of the old motors are horrible in comparison, the gas mileage significantly worse. But in order to accomplish these things the motors are bigger in size and weight. They are made for today's boats.

I remember a family's typical boat was around 16' in the 1960's to 70's. A 14 or 15' speed boat was common. Small lightweight. Look in your garages and see what is being sold today. 20'+ bass and CC fishing. Cruising boats start at 24'. Boats for the bay and ocean start at 24'-28'. Ya can't push these boats with little no grunt motors.

That doesn't mean I like all that is going on. I feel the high performance small boat segment was left behind by the boat manufacturers and motor manufacturers. But then again they were selling us on bigger and badder and we bought them. We abandoned the 15' Allisons, 14' Hydrostreams. We abandoned racing we went to STV's, big Allisons, 20'+ with hugh v-6 motors. So ultimately we are to blame. The consumer.
For a somparison look at the auto industry. We all drive big SUV's. What happened to the MG, Triumph, small Datsun/Nissan etc? even the small cars got a lot bigger.

Just my opinion for what it is worth. It was free so....

[Dave S]

I don't belive what the book says about weight or HP, just the bean counters BS the people buying their motors.:rolleyes: The old 1750 had a real ligth duty swivel bracket and clamp brackets. The next swivel bracket is the Off shore type, also used, maybe made for the 550 lb 300 hp 3.4 ??? That bracket is very heavy with out the pump. The 2.0 block, with cast in Chunks of sleeves is about 20 lbs heavyer than the 2.4. I like the newer ART piston with the keystone rings, I don't think they will carbon up as easy as the flat rings. It would be nice to put them in the old pistons. As far as the old pistons being forged, thats what the book says. I could buy that they could be low pressure cast/ forged. Just how many PSI to be called forged?

[150aintenuff]

I was mearly stating a trend in the industry... TO HEAVY PIGS... .. It is getting to the point where i wouldnt even hang a new V6 on my 20' 2500 lb fishingboat... they are just to heavy and only the 300 and 280's are light enough to be reasonable.. and as for DFI or emmission motors the 200xs and new 2.5 are the only ones worth their salt that dont weigh over 500 lbs.. even with todays case of 2footitus the 1500 is a good strong runner on say a 17' bassboat much like a DFI 115 would be a good runner on the same hull... I just thought it would be interesting to take a fresh 1500 which was about 115 -125 hp and pit it against a new 115-125 hp and see which setup ran better overall.. if hp is equal it could be made a fair test for new vs old.. thats all. and i dont believe that the new engines are all that better for environment.... they still burn oil and still use about the same fuel and oil at WOT as the older ones do....


i havent seen a new dfi or 4stk that varies much off of the 10% fuel/hp ratio.... even V.V.T. EFI 4stks are still between 11-12% ratio.

[ggarland]

Don't worry about arguing here. Jeff and I go at each other all the time, but we are still the best of friends and I will back him to the wall when it comes down to it..... we just don't agree all the time is all. A difference in opinion is what keeps the board alive and kicking, and us for that matter. Be a pretty dull place if we all had the same opinion and agreed all the time now wouldn't it? That is the neat thing about free speech. It's free!! And besides, where else can you get info like this except here? EVERYBODY has a say here, man, and it all has value. Cheers!

George

[77STREAM]

Break it in before I come up there!!!!!! That way we can run for a day or two before I have to leave!!! I would hate to drive all the way there to have to go slow for a 10 hour day!! You might like driving it with the Jackplate, Solid Mounts and Dual Cable steering. It should handle a little different then your Viper with the S/S.

Pete

[150aintenuff]

here here george...


AT LEAST S&F LETS YOU HAVE AN OPINION.... I'VE Been kicked off boards because my opinion didnt agree with the board because a sponsor of the site took offense at it....

NOW I WILL GO BACK TO TOPIC.

[Raceman]

"AT LEAST S&F LETS YOU HAVE AN OPINION.... I'VE Been kicked off boards because my opinion didnt agree with the board because a sponsor of the site took offense at it...."

It don't work that way around here. Around here we kick sponsors off that don't agree with OUR opinions. :D :D :D

[1BadAction]

Originally posted by npartin
even a 21'boat would run better with a good old 1500XS or T3 even than thatpiglet could ever think of....

thats not an opinion, its pure BS. talking out your ass never gets you anywhere here either. you have never been in a hull with a verado if you think the above mentioned scenerio is even close to the truth. You should keep your mouth shut about these new motors untill you get a chance to run one, because its nothing like what your skewed little mind thinks it is... but then again, i would expect no less from somebody who thinks a N/A 6100 rpm suzuki is faster on top end than a blown 6400 rpm verado. dood, newsflash, THERE IS NO COMPARISON! between a zuki OR the old motors. end of story.

if you have a problem with that PM me, because you have already got this thread enough off-topic.

[150aintenuff]

I may have never ran a verado YET!!! as there is only 1 in the area here, AND IT ISNT EVEN STILL RIGGED UP!!! BUT I do know OLD TECHNOLOGY WORKS!!! Try telling anyone here different... If it didnt WE all might Be screwed and this board wouldnt exist... I most certainly would be hapier with a old oil pukin smoke spittin 2 stk than an engine that has parts that the industry has never seen before EVEN IF AUTOMOBILES HAS USED IT FOR YEARS!!!!!... IF IT AINT BORKE DONT FIX IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


CALL IT BS or what you will... BUT GIVE ME A 1500XS and a 14'ALLISON ANYDAY you can have your VERADO on A 21'OR LARGER TANK ANYDAY!!!!

[1BadAction]

oh noo, you wanted to compare 21' boats... dont backpeddle to a 14 allison now. I didnt say old tech doesnt work, but show me an old merc inline that will push a big boat like a verado will, and I will eat that verado piece by piece, supercharger and all.

as for if it aint broke, dont fix it? you still driving a steam engined car? i didnt think so.

[150aintenuff]

find me a 250hp inline T2X built to hilt ??? and Ill even supply the 21'boat....


I may not drive a steam engine car, but my car is of 1940's technology... its amaising how long injector pumps have been around.....

[1BadAction]

So, you want an ultra hot modified raised port, everything custom $30,000 motor that Looks like an old inline? it might last through break in, and even if it did last, the thing wouldnt have the torque to pull a big boat out of the hole...

sound crazy? thats because the only place a 250hp t2x will ever exist is in your dreams, sorry, get over it.

[150aintenuff]

nevermind....

[Dave S]

They are makeing motors better. But steam was pretty good, it moved locomotives back when I was a young man.:p Just kidding.

[Jeff_G]

Yeah and steam was the only power back when George was a young man. Yes George bleeds black, coal dust.

Aren't we all a little off topic. Lets go back to fighting about forged VS cast in inlines.

:D

[sho305]

Most engines they say to go forged at X rpms right? What about the inline, what rpms would it need them at?

[dale robertson]

I haven't rebuilt an inline 6 in 30 yrs. but if I did one today it would have Wiseco's in it. I have used them in a few other engines and I like them. If the engine is set up properly I can't see why they won't be superior to those junky looking cast fishing motor pistons. I don't remember seeing those in any of the inlines I took apart. I always thought the Merc pistons looked superior to the cast Alcoa blobs used in the O.M.C's.
Now that should get everybody going

[bridges]

I thought of another difference if you are trying to tell if a piston is forged or not:

Lack of undercuts. There can be no undercuts inside a forged piston because it has to be released from the forge that stamped it into shape. For this reason, the part numbers will be on the inner crown, not the inside of the skirt wall like on a cast piston. There may also be vertical striation lines inside the piston.

[Jeff_G]

The only way to tell for sure is to break the piston, not cut it, and examine the grain orentation under a microscope or at least a 10X loop.
Mercury used many different manufacturers. I know they made a pressure die cast piston which is different from a "common" pour mold cast piston.
The reason not to use a forged piston in an inline is the thermal properties of the motor are quite high. That is one of the reasons when something is barely off they let go so easily. Bad gas, overheating, timing problems, air leaks. A forged piston does run marginally hotter than the cast. In addition as has been said many times before they expand differently. That is why even Weisco recommends different clearances when you use their pistons. They still do not stay 100% round in the cylinder.

I would have no problem running Weisco's in other applications.
If one wants to use Weisco's go ahead. I stand on 30 years in the business and 27 years racing most of them inlines. That's only my opinion take it as you want.

[ggarland]

Jeff:
I will go along with that....... The inlines did run on the ragged edge of detonation, and with the crap that they pass off as fuel today I can understand the sensitivity to problems. Cripes, this is getting bad. I am agreeing with you WAY too much lately, we need to get into it again, spice things up!!! LOL

BTW where are those pics of your new grandkid I asked you to post????


George

[Jeff_G]

We can always talk about cylinder wall finish and the tools used!!! :eek:

[ggarland]

Well that will do it!!! LOL

Naw, too close to Christmas, gotta keep a festive spirit going here !! In the new year however.......

Merry Christmas, Jeff


George :)

[Bruster]

Not trying to be a smart ass but, if you never knew Mercury made forged pistons for the inlines until now, how do you you have never ran them? :eek:

[Jeff_G]

Bruce, I can't ever remember ever seeing a Mercury forged piston in an inline. Neither has many of the finest engine guys and guys that raced them through out the 70's. This includes Dean Pink, Benny Robertson, Gary Kapit, Sam Haraway, myself, and some others including some on ths board, as well as some Mercury employees I have asked. The only mention I have ever seen of a forged piston was the 1976 sales brochure that was posted here. It also seems that if they did that it was only of one or maybe two years. At this point I can't prove that they didn't so I just went with the evidence presented, the sales brochure, and said I was wrong in my belief.
I also pointed out that Mercury used many different piston manufacturers and different casting processes, including high pressure die casting which looks externally like a forged piston.
So what would you have me say further on the subject? Should I get on my knees and beg the forgiveness of the inline gods that I have put forth my opinion that they didn't use forged?

Let me give you a direct quote from a friend from Mercury, "The pistons that "Hi-Perf" sold were cast. There might have been some
forged pistons around in Engineering but I don't remember that we sold any
over the counter.

I don't remember the brochure stating the forged piston but gee that was 30
years ago we may have had something that stated that. I'll look at some of
the old literature and if I find anything I'll let you know."

So was there a forged piston or did someone in marketing fudge a bit on the sales brochure? I truly don't know. I will tell you that any piston from Mercury for the last 25+ years were cast and the only forged piston I know of is Weisco and I personally do not recommend a forged piston in an inline.

[Raceman]

This was my comment on the 3rd page of this thread:

"The 1500XS DID NOT have a different part number piston. If there was ever a forged replacement piston for it I was never aware of it."

After all the additional comments and opinions I decided to quit commenting myself because I was unsure, except to the extent that I've never pulled a powerhead down and noticed a piston that appeared to be forged. I've since looked at all of the dissassembled stuff I have and still don't see any surprises. One thing that does strike me as obvious is that if Merc had substitute forged pistons for a year they'd have most likely come with service bulletins on increased clearance requirements. To ad to the comments from the Merc guys, my friend who I quote frequently, who worked for Merc for 20+ years in both warranty and as a Service School instructor said they didn't do it in production engines to the best of his knowledge.

As for the brochure, I wonder if it could be a case of marketing people fudging, or more likely ADVERTISING people with little or no actual product knowledge throwing in an incorrect detail that wasn't caught in proofreading.

[sho305]

So many of you are saying any good condition 1400/1500/XS piston you would put in a perf motor and run ~6500rpm?

[Raceman]

Yes, BUT................... I've never seen a 1500 powered boat that wasn't SLOWER on top at 6500 than at an RPM SLIGHTLY UNDER 6K. Accelerate better pitched to turn 6K? YES. Faster on top? NO

[Jeff_G]

SHO,my motor consistantly turns 6,800 to 7,000 using a 14 X 26 cleaver with no problems to the piston. (At least not from the RPM's)

[sho305]

No, no; you are right Raceman but I mean from a durability standpoint. These racing guys say they over-rev particularly on a short course from 6300-7K to get out of the corners (even though that's past the power peak). So if they are using vanilla inline pistons above the 6300rpm Merc recommended max for the XS (if they are all the same), then durability must not be an issue. I'm no piston guru by far, but all I know is mostly you only use forged when you exceed the rpm limits for that size cast piston...forged is often not as good in other respects like heat/tolerances/etc :confused: (right?) So in effect why use forged, though it might sound cool in the advertising...

Thanks Jeff_G, that is what I mean. So they must be the same if you use all of them, or they are all pretty good for up to 7K or so anyway.

Many sleds/bikes run over 7Krpm with cast, though cars don't seem to like it...I assume from larger bore/stroke sizes, piston mass, etc., causing them to need to swap over at a lower rpm.

[Jeff_G]

Depending on the design of the piston and the application the forged piston is marginally stronger, in some cases. One of the reasons engineers call for forged pistons is when one does have a piston failure (in high performance situations) the cast piston does tend to shatter and cause more damage. I have never seen this in an inline but have in some v-6 applications. The forged piston, there again the design being the criteria, due to the orientation of the metal molecules can have a stronger wrist pin area than cast.
I would guess that the design limits for the inline piston is somewhere around 8,500 give or take a few. I have never seen an inline turn much over the mid 7,000 range. even there they were on tunnels and had no failures from rpm. Keep in mind most racing use of the inlines stopped in the early 80's. Some continued sporatically to the early 90's. When Formula V was created in 1993 there were quite a few inlines running. Today I believe I am the only one still running an inline in sanctioned competition. In practicality the heyday of the inlines were the mid to late 70's. Their developmental peak was also during this time. Although a great engine, they are somewhat a dinosaur. I would run a more modern motor except I can't find anything that is faster in the 100 cubic inch range. A tribute to the pre computer designers and engineers of the early 70's!

[ggarland]

.... on this forged vs non forged issue in the inlines, I have a radical idea: Why don't we talk about something else? It is getting beat to death and I suspect we are no closer to a real answer than before. But I concur with both of you on all your points made, all sound, all valid. And no Jeff, you do not have to beg the inline gods or anyone else, your knowlage and opinions are well respected by me. Just don't expect me to agree all the time is all. I love to banter with you, and I mean that in the best way, my friend. But man, I am getting a headache here. Tell me what you want for Christmas instead! Cheers.

George

[Bruster]

We can always talk about cylinder wall finish and the tools used!!! :eek:

Jeff
I wasn't trying to be a dick about the forged pistons, simply a question. It just seems there were facts mentioned you weren't aware of 20 years ago and you have probably have built more than 1 or 2 motors over that period of time. Enough about pistons... 2 subjects I would like to hear more about is cylinder wall finish, what's best?, and reed block to crankshaft clearances.
We are listening......

[59powercat1400]

geez, when you guys get into it, you really get into it! here's a question for you, how much compression should a 1500 have? the guy who sold it to me posted it had 150lbs. of course I get it home and it has 120, but that's another story. another problem with buying a motor so far from home. dick.

[ggarland]

Jeff and I have had some real good scraps in the past, makes this look like a group hug!!! All in fun however, and we know where to draw the line.

120 sounds good, as long as all the jugs read the same. Get a leakdown test as well to be sure.

George

[Mark75H]

Dick, I wouldn't worry about the 120/150 difference. Different gages and different batteries can easily explain that.

[59powercat1400]

thanks guys. I won't worry about it for now. dick.

[sho305]

I checked mine with the coil off, wot, no plugs, on starter and got 120-122 on all. Don't think it has been apart ever. 1973, but sat 10 yr or so before I got it. I found a leakdown for $35 here but have not picked it up yet, a plews...not sure if they are good. It would get up to max in say 4-5 revolutions I would guess, then stay there. Must have been close to 1000 cranking speed with no plugs? Was partly warm.


There is a lot of things those sliderule guys made right...like many military aircraft, our land phone system, air control system....you get the idea. When you are bored find out where (and when) the rocket motor came from for the space shuttle...:D that is funny.

[150aintenuff]

59powercat

your readings are most likly different model and type of gauge more than anything

My engine (150 v6) will read around 110-120 with my gauge and 140-150 with a friends gauge, the only difference being the gauge interestingly enough though when 100lb shop air is aplied to them both to varify their accuracy they read identical at 100 lbs so it is just ouw the gauges react to the pulses i am assuming and as long as the readings are consistant you are ok. now if you readings look like my 8 hp i might worry.... 65 in one cylinder and 35 in other, and yes she still runs just fine.....and yes there is a story behind it being so low.

[Jeff_G]

Bruce the cylinder wall finish goes back to a discussion George and I had almost a year ago. Basically when I finish a bore job I use a brush hone for the final finish. This gives the proper finish to the walls of the cylinder and also lightly champhers and removes rough edges from the ports, all without changing the cylinder size.

When I use the brush hone I hone in a forward rotation and then counter rotation, I have found a battery operated drill is fine for this, at medium speed, and I now use Gunk spray engine cleaner for the lube. The Gunk lubes great, keeps the stones clean and is very easy to clean the motor afterwards. Use it continuously while honing. You can do the entire motor in about 10 minutes. I also use the brush hone when deglazing and re-ringing.

There is no reed block to crankshaft clearance spec that I know of. I'm sure there is but maybe only in Mercury Engineering. What is very important is the condition of the grooves and ridges on the inside of the reed cages. The reed cages do two things, provide a bearing surface for the crank and act as a seal between cylinders.

To check the reed cages, seperate them, look at the sideways so you can plainly see the top of the ridges (where they ride on the crankshaft). If there is any mushrooming of the ridges the cages need replacement. It is one of the most overlooked items on a rebuild. Simple check. Check both sides of the half, sometimes they wear differently. If there is a lot of wear think about replacing the main bearings as well. You might also want to check the crank for straightness on a set of v blocks. If there is any wobble in the bearing surfaces the crank must be replaced.

[ggarland]

Jeff:

A discussion? That is like saying the universe is pretty big!!!! (LOL) We tore up trees over that one, me boyo. Still, looking back it was a lot of fun, (can't believe it was a year ago already) and even though we wanted to kill each other we remained friends in the end. But I guess we both took our lumps. As to the reed blocks, I agree with what you say, they should be replaced if worn. As to the cylinder wall finish, well you know I won't go there once I found out that you are packin' ! Cheers man.


George

[Bruster]

Bruce the cylinder wall finish goes back to a discussion George and I had almost a year ago.
Jeff-
Thanks! :)
2 Questions:
What grit hone are you using, and where is this dicussion located?

[Powercat]

Back to the boat/motor that began this thread,,,,
Here is the internet production video of the boat
running and it's story... Check it out...

http://www.powercatboat.com/video/video.html

[Jeff_G]

The discussion was in a newsgroup. I use 180 grit silicon carbide Flex-hone. I hone for about 30 sec. to 1 minute depending on what I am trying to accomplish. By using the brush hone you will get a better surface finish, clean up port edges and have better ring seating and life than with any other method, while at the same time you will not create any out of round or taper unlike a 3 finger hone or a ridgid hone. BTW this is how Mercury does it from the factory. Absolutely the best way to finish a cylinder surface.

[bridges]

1972 catalog..........

[bridges]

nice stackers---72 catalog, Havasu 1970

[bridges]

Merc was not "fudging the info" on forged pistons. Mercury kept making forged pistons into the 70's. I have shown photographic and printed proof (after all, you asked for it). For the record, I think they probably quit using them in 76 or 77. There is no mention of them in the '77 catalog. It is possible they were not ever used in the 1500XS, regardless of the catalog info. I never said that racing div sold them. But many were made and used in production models in the 70's, including 1500's and I have some---believe it or not!

You are welcome to come visit and I'll let you hold a Merc 3 ring, tall deflector forged piston in your hand and compare it with a cast---but nobody is going to cut one of 'em and look at it with 10X loupes. :D .

[Jeff_G]

The plot gets thicker.
The piston you cite an example of has a casting number of 745-4973 This piston is a three ring (square) piston, BUT did you know it is also a two ring piston. Wait Mercury didn't make a two square ring piston for the production inline 6 did they? Or did they make it for the 850 motor. So now we have 2 pistons with the same casting number. I have both pistons so I know this for a fact.

So then I took a three ring piston that looked exactly like the one in your pisture, a perfectly good piston, and broke a piece off of the skirt. I examined it under a loop then my microscope. I scanned it so maybe we can see the grain. Guess what..... anybody?

In the scan you see the side of the piston skirt.

I added this pic to give a better look of the grain.

[CrayzKirk]

I don't see no stinking grain...

Or, I don't know what to look for...

Kirk S.

[sho305]

Maybe that's part of the early Z-Rod metallurgy technology study that was top secret back then.....:D lol

Now that new pic looks just like every other broken cast piston I've seen, but then I have not seen that many broken forged ones...the few I did were beat to death not broken.

[Jeff_G]

OK guys, I posted a picture of a cut away of a piston yet no opinions? George, ya ole goat, how come you're not putting forth your opinion? For such a talked about subject all of a sudden everything is quiet? :p

[dale robertson]

You know what they say about opinions. It looks cast to me.

Hone it straight and true with a sunnen hone (360grit) and finish with a flex hone. It will be just right for the Wiseco's.

Merry Christmas
Dale

[Raceman]

Looks cast to me too.

[Bruster]

.... you can't read the newspaper anymore with out glasses let alone the grain structure of a piston, in a picture. Take your piston samples, make lab mounts then look the the result with a microscope and I'll listen a little more intently :confused:
Cast or forged, the motors are only running 6500 rpm and either will 'er done. :cool:

[ggarland]

" George, ya ole goat, how come you're not putting forth your opinion? For such a talked about subject all of a sudden everything is quiet? "

Just thinking about it for a while. Not sure how looking at a broken skirt is going to tell you anything about the metallurgy of the material..... Never seen it done like that before, but what do I know. :confused:

George

[59powercat1400]

I got my new short mid from Gus yesterday, thanks Gus! With the new tower, the cleaver I got from Dale and a good tune, maybe this thing will go like everyone says. I can't wait for spring to try it out. Dick. :)

[dale robertson]

Hope the project turns out well and that franken kitty picks her tail up. Are you going to use solid mounts? You will probably have to wear a walk-man playing a C.D. of twin Scotts wailing at wot to get the right sensation.

[59powercat1400]

yup, I got a set of solid mounts from Bob's. I never thought about it but you're right about the walkman. Dick.

[wigymnastics]

In regard to 38 degrees; maybe it was too cold and it's jetted for more like a 70 degree day.

How about a Rockwell test to figure out cast -vs- forged?

[59powercat1400]

I think you're right. It wasn't really a fair test. At least we got to run it before it iced up. We'll try it again in the spring with the short mid and see if we can do better.

[ggarland]

......won't tell you anything I am afraid. Forging will not make the metal harder, just tougher. No, there has to be another way to tell. :confused:

George

[Bruster]

......won't tell you anything I am afraid. Forging will not make the metal harder, just tougher. No, there has to be another way to tell. :confused:


George


Again, Take your piston samples, make lab mounts then look the the result with a microscope.
Cast or forged, the motors are only running 6500 rpm, don't worry about it.

Let's talk about cylinder wall finish, and break in, somethings that matter. :eek: :eek:

[sho305]

Yeah, where did everyone go? Here the thermo is down at 8 today so I didn't even want to go feed the poor dog out there...don't worry as she has her own condo inside, but I figured after the holidays people would be back here ripping on something.

[150aintenuff]

Yeah, where did everyone go? Here the thermo is down at 8 today so I didn't even want to go feed the poor dog out there...don't worry as she has her own condo inside, but I figured after the holidays people would be back here ripping on something.

MLK JR DAY.... Three day Weekend for most.... figure they are all out and about

[Mark75H]

I think Sho is talking about more of a weekly trend rather than this specific weekend or day.

Posts do seem to be slowing down here

[ggarland]

but before we leave the subject, tell me just what we would be looking for in that microscope?

George :confused:

[Bruster]

but before we leave the subject, tell me just what we would be looking for in that microscope?

George :confused:

Grain structure. :p
Now let's talk about cylinder finish and breaking that motor in.
Ever break in a chain saw?

[Dave S]

Merc allways said they had forged pistons. From the days of the KG7 and KG9. Till the days of the 110 SS till the days of the 150XS. I just belived them at their word. The newer ones are cast, there ART pistons. Don't mean to start any arguements just what I have belived to be true. I don't care what they are made of, I just want them round with no scractches or burnt tops. Then I put them in and it runs. Happy Day off. :cool:

[ggarland]

Hang on a minute; I need a little more information than that. Just what does a forged grain structure look like as compared to a cast one? Under what conditions must the sample coupon be prepared? Dave and I find this subject fascinating and would like to know more..... Wouldn’t we, Dave?

George

[wigymnastics]

Guys,

I can get this information. I've done this before but I'll need to review. It's been a few years.

While you're waiting, does anyone know how to get more horsepower out of a 950 if I'm willing to tear it down and put in crank with a longer stroke, different reeds, and carburetor work?? Is this possible?

[Raceman]

I don't know what crank you could put in a 950 that has more stroke, so this is only theoretical, BUT, changing the stroke in a two stroke changes the port timing. Since given degrees of crankshaft rotation move the piston farther down the cyl wall with a longer stroke, you'll raise the port timing and lower the compression at the same time.

[Mark75H]

Its probably not possible. Most likely the big ends of the con rods would hit the insides of the crankcase front and back. Far easier to just find a 99ci block (there are millions) than to modify the 89.

[Bruster]

Hang on a minute; I need a little more information than that. Just what does a forged grain structure look like as compared to a cast one? Under what conditions must the sample coupon be prepared? Dave and I find this subject fascinating and would like to know more..... Wouldn’t we, Dave?

George

OK-
The samples are cut from a mystery piston in this example, and encapsulated in a plastic mount. This mount will have 1 edge very finely polished exposing the sample material grain structure. The mount then can be examined under a microscope and will read like a book.

This is very general example of what you would expect to see. There are many factors that control the grain structure of a casting or forging.

A cast part will have grain structure that will be mostly circular in shape and fairly uniform in (maximum) size with visable voids between the grains.

A similar forged part would have a smaller circular to elongated shaped grain(depending on where and which direction the sample is cut from) with no voids between the grains.

Hope this helps :eek:

[Dave S]

As far as the old 95 merc you can put on the bigger carbs off a 110 or 100 hp. Also a pointless ingition if you don't have that. The reeds in the 95 hp are long and narrow the 110 are tear droped shaped, but chip at the ends. I have made my own reeds for those motors but you migth be able the buy glass reeds now. If you can get the crank welded stroked .030 migth help a bit, raise the compression. Those old motors most of the time have a bad crank surface because the bearings slide rather than roll. I think the combustion chamber is better than a 99.9 cid style motor with todays gas. Also the 3 ring pistons are better than the 2 rings, they have narrower rings. Hope this helps.

[wigymnastics]

Thanks for the feedback on the 950. Here's what I've got.

In general, sample preparation involves obtaining a flat mirror-like finish which can be examined by reflecting light.

The sequence of operations is typically as follows:

a) If the sample is too small or has an awkward shape, it should be mounted in plastic for easy handling.

b) By means of a belt sander or wet abrasive tool grind a flat surface and bevel the corners or edges. Avoid excessive heat or deforming the sample.

c) Using wet silicon carbide papers of successively finer grades, obtain a finely ground surface covered with even parallel scratches from the smoothest paper. Excessive pressure is not required. It is important to wash the sample and your fingers before moving on to a finer paper in order to avoid carrying over the courser abrasive particles. The common rule is to grind on each wheel for twice as long as it took to remove the scratches from the previous grade, turning the specimen through approximately 90 degrees at each grade change.

d) Having thoroughly washed away all traces of grinding material, a final surface is prepared by polishing the surface on a polishing wheel which is covered with a fine abrasive paste or slurry. A particle size of 1 micrometer will give a satisfactory surface for most samples. Again, excessive pressure is not required.

e) Following the preparation of a near perfect mirror finish, it is usual to etch the specimen lightly to reveal details of the microstructure.

Grinding wheels: 80 grit, 120 grit, 240 grit, 400 grit, polishing wheel.

Microscope: X400 magnification

After all that you've a sample:). I need to review for what one would expect to see in the viewfinder.

[ggarland]

Thanks boys, for the info. I want to check into this a bit more, fascinating subject.

George

[Powercat]

This is a follow up to the boat/motor that this thread was
started about... She is now running in the high 70's consistently
and Dick says it is a real blast to drive... Looking for that last little
bit to break into the 80's...
....................
[ Photo credit to http://www.retroboats.net/ ]

[sho305]

That looks great, and thats hauling!!:cool:

[99fxst99]

Hey Dale-
You still out there?
Smokey

[ssmith007]

Anyone ever hear of welding the top of the jugs on an I6 to raise compression? Is that a possible racing mod? Smitty

[Mark75H]

Yes, it is possible for racing, but it restricts the motor to race gas or alcohol.

[ssmith007]

Do they weld pieces or just use welding sticks for material? Any idea what the speed record with an inline was? Smitty

[Mark75H]

Two methods were used, completely cutting off the head and welding on a completely new shape or just welding in an insert. Often the welding distorted the bores so much that they had to be bored out to correct out of round.

The speed record was 136+ ... it has its own thread: http://forums.screamandfly.com/forums/showthread.php?t=128661

[Raceman]

Do they weld pieces or just use welding sticks for material? Any idea what the speed record with an inline was? Smitty

I think the engines that had welding done in the combustion chambers were more of the old PURE crossflow design, rather than the modified crossflow or "direct charge" as Merc branded the 70 and newer engines (plus the '69 Super BP's). My personal opinion is that if you try and go welding material into the combustion chamber of a direct charge inline 6 you'll likely create a pile of scrap metal. Jeff_G has some innovative ideas for slightly raising compression on one of these engines, but for a lake toy I doubt that the reward would be worth the effort.

I believe the speed record for a J Sport boat (1500XS on a tunnel boat) was just over 100 MPH. The record that Sam linked above was a special T2X race engine with specific mods, run on a hydro just for that purpose.

[sho305]

If IIRC most could get about 82 or 83mph out of a 15' Viper with a fresh inline, on gps. Jeff said he could get more with mod engines but not sure if he ever tried a big prop?