Building/ freshening up my 175 big bore crossflow

OK guys. I am right in the beginning stages of my build. There have been numerous postings by me already about various aspects of this engine. Originally, I was just going to run it, because the guy I got it from said it was in good shape......as was good compression when he checked it a year ago. The motor is all original with good compression. My lowest cylinder I think was 105? My highest was 112....and these were with the stock bathtub heads. I was just going to put on my set of high compression heads I got off EBAY, jet it up a size , if needed, and let 'er eat. But I wanted to look in the inspection covers to see how things looked from the side.......4 of the 6 looked great. I couldn't get cylinders 4 and 6 's inspection covers off because of the starter's mounting boss. But as soon as I opened a cover up, I remembered the factory fangs hanging down in the intake ports. ANd I cant leave that alone There's also casting flash all through the intake tract that needs to be removed. I also obtained a set of 2+2 reeds from Chris Carson. So this was my original intent.......clean up the intake run, mild port clean-up, new reeds and go enjoy.

I finally was able to tear the motor down today. I was a little disappointed to see that piston number 4 has contacted the bore. Its a pretty good scar in two spots.....yet no ring scoring in the sleeve or on the rings themselves. So, I need to obtain a new piston.

I am going to try and post some pics. I do not any pics of the scored piston...yet. I have pics, so far, of the cages started, the cowling being repaired so I can cut louvers in it, the old dirty motor itself, my heads, and a little more.

Pics to come........I hope

Attachment 437515Attachment 437516Attachment 437517Attachment 437518

I have pics of the before and during.....no afters yet. Pic #3 was the image of the busted corner. I removed all the badging front and back. The inside has 2oz surfboard glass on the inside to back all those little holes. I used bondo glass for the front filling. The busted corner was backed with 3 layers of 6oz cloth to support the corner. Before the resin hardened, I jammed some resin and pieces of cut glass to build it up.....so I didn't have to use a lot of bondo or bondo glass. It worked. I sanded it today and there are only 3 small divots to fill and then skim with a fairing compound. I still need to get the stickers off anyways. They come off with a heat gun pretty easily.

More on this later...........

OH yeah, the gasket is the biggest pain-in-the-butt to clean up. It's black when it should be white. I soaked it in smoking hot bleach water....didn't do much. The only thing I have found that works is a scrub pad with acetone!! Its horrible:mad:

This is to show what I started with and what the end product will be. I blended all the edges and left no sharp corners or edges where the air leaves the cage.Attachment 437521

Sorry the cages are backwards:rolleyes:............the before is on the right.............my reed petals look like the left cage. Now to do 5 more. I had a learning curve as far as time goes. I learned at the very end how to cut them and not take forever. It should only take me about a 1/2 hour each cage from here on out. I still have to lap them thought. I am just going to take it down to 320.

I think they will flow a lot more than the stock reeds. I wanted to go this route because I saw on the loopers how much larger the reed cages are for them. I said,"i want too." So, this is me making the cages larger.;)

Going to use emblems or decals on cowl? Or nothing
List of mods you plan in doing?

Well 1st thing I notice in all that was u least need buy 1 piston? So u plan on reusing everything but rings and 1 piston? Measure ,measure and measure again. Bores that is , I'd go 15 over and new slugs for a good reliable motor , can b done but measure measure again! Haven't had gud luck just tryin to rering , best of luck. But again mrchartz has couple strong rudes , maybe the "SLOMC" has thicker more forgiving cyl. Sorry I couldn't resist.. plz 4give me hahahahah

Quote:

---

Originally Posted by mrichartz

Going to use emblems or decals on cowl? Or nothing
List of mods you plan in doing?

---

I am not sure about emblems or decals yet. I did go to a website..........outboard decals.com.........I think, And I may get a set of the 175 gt stickers. Undecided. I will paint the motor white. I forgot to mention that only thing usable off this motor was the powerhead and trim pump and lower. Tge mid was not salvageable because I couldn't get it undone............salt and galvanic reaction between stainless and aluminum. It cost me the adapter, mid, and steering head. But I have a 20" motor sitting on a stand with a 200 powerhead that is in perfect condition, but needs helicoils put in on some heads bolts............nothing worse than torqueing them down to twenty and it keeps on spinning..........doh!!

My List of mods are this:

1)reeds cages cut/blended for new petals

2)intake tract completely removed/blended of all the flashing. I was looking today where the scalloping normally takes place, I will blend that lower ridge down to a smooth transition......it will make more space for incoming air as well as remove turbulence

3) I will remove all the fangs in the ports both intake and exhaust...........both sides have them. I will also blend the intake ports instead of straight walls........it can only help...I know it can't hurt. I may open up the center port in both the intake and exhaust side.........center only....not all three.

4) open up the adapter..........it has some nasty straight line blocks...............need to remove the corners and blend it into smooth tapers

5) open up the filler blocks for cylinder # 3 and 4. The upper and lower cylinders have this huge amount of space. But the mid cylinders look like they are the red headed step child.........kinda an after thought......very narrow and short. I actually would like some advise on what to do about this.

6) the intake manifold........I am really thinking about removing 1/8-1/4 material between the 2 barrels. I would mirror the top cut (where the choke machining is) at the bottom and cut that all the way from top to bottom.....knife edge the center divider that remained. The intake manifold has a lot of casting that needs to be removed/smoothed too. I just need advising about the cutting/milling. will that hurt performance or help.....lose bottom end only to make it peaky? dunno..............I don't want that. SO, I will hold off and continue moving on other stuff first.

7)repairing of the cowl and cutting louvers for looks and make sure it has enough air to support the engines needs.

8) I have velocity stacks coming.............always wanted a set..............finally got 'em. If it don't help performance, at least it will look good...instead of the old plate design.

9) powder coating chrome of various pieces to make it look nice............water jacket covers, t-stat covers, stacks, etc.

10) re-jetting so as to not blow my engine up..............LOL!!

Quote:

---

Originally Posted by Merc 2.5

Well 1st thing I notice in all that was u least need buy 1 piston? So u plan on reusing everything but rings and 1 piston? Measure ,measure and measure again. Bores that is , I'd go 15 over and new slugs for a good reliable motor , can b done but measure measure again! Haven't had gud luck just tryin to rering , best of luck. But again mrchartz has couple strong rudes , maybe the "SLOMC" has thicker more forgiving cyl. Sorry I couldn't resist.. plz 4give me hahahahah

---

I do plan on measuring since I have things apart. But no, I am reusing the rings in in the good pistons......don't need to change them. Where I install a new piston, I will install new rings and hone cylinder too. But I will measure top and bottom of bore to see taper....etc. and bore if necessary and then bore everything I guess. But seriously, theres no scarring in the sleeve.........the ring never made contact, or at least I cant see evidence of it. But I just cracked it open today. No measuring done yet.

I did forget to mention that this engine has spent most of its life sitting on a trailer. If had more use than that, there is no way I would have been able to open this motor up because of salt and time. I am amzed I got the exhaust open.........scared to try and take it off.......come to find out, I only broke one bolt at the bottom.

I might have Evinrude emblems to donate if you want
Might need to piece one it's a clean crack and can't see when put together.. clean and paint.
What year 200 crossflow I assume..Time-serts work better.
What's the motor going on?

Quote:

---

Originally Posted by mrichartz

I might have Evinrude emblems to donate if you want
Might need to piece one it's a clean crack and can't see when put together.. clean and paint.
What year 200 crossflow I assume..Time-serts work better.
What's the motor going on?

---

I'll take the emblems;)..........might give me more ideas for paint design etc. Unsure of the year of the 200. I got it as a reman 150gt powerhead about 7 years ago. They didn't know what they gave me. I only found out because I decided to find out why their p-head kept leaking oil down the mid when I took it out of the water.......used bearings, forged and cast pistons, both styles of bearings for the rods.....a 2700dollar hodge podge of rebuilt mess............oh yeah.........broken sealing ring on the crank...........the oil leak. It was then I saw the ports were as big as a 235's ports..........especially the exhaust, where a 150 has puny ports on the exhaust side. So, I got a 200 block out of the mess. But I have to fix the head bolt threads.....2 I think. As a matter of fact, the ports on my visitor page is that engine.

pics. I only removed the fang in the middle. I compared these to a bad 150gt block I have........these are huge. Is been sitting for 3-4 years now, run for 2 minutes since I put it back together........and only 10 hours run time b4 that.

Quote:

---

Originally Posted by keefallan

I'll take the emblems;)..........might give me more ideas for paint design etc. Unsure of the year of the 200. I got it as a reman 150gt powerhead about 7 years ago. They didn't know what they gave me. I only found out because I decided to find out why their p-head kept leaking oil down the mid when I took it out of the water.......used bearings, forged and cast pistons, both styles of bearings for the rods.....a 2700dollar hodge podge of rebuilt mess............oh yeah.........broken sealing ring on the crank...........the oil leak. It was then I saw the ports were as big as a 235's ports..........especially the exhaust, where a 150 has puny ports on the exhaust side. So, I got a 200 block out of the mess. But I have to fix the head bolt threads.....2 I think. As a matter of fact, the ports on my visitor page is that engine.

---

Ah damn could have gotten them in the other box too but it went out already

back in the 80s I got a CCC evinrude... I used the block as a template to build a bunch of other motors to CCC type specs...blend,scallop,port ,boost ports etc,etc,....they ran good...the CCC had 6 two barrel carbs, so I figured i needed more air for the clones, so I tried cross drilling the intake...this pretty much sucked ...the motors became almost untunable at anything less than WOT...would only idle so high rpm that I would just lock the shifter and crank it up in gear so I wouldn't break anything when it shifted...then went to L&S big bore carbs..mill the 2 bbls out to 1.5" ..they worked pretty well...so, in my opinion ...don't mess with the intake...it will make your motor a bitch for very minimal rpm gain up top..

anyone tried to put mid bore looper carbs on a custom intake?
They are slightly bigger then 1 3/8 but I would guess with port and stb separate you end up with a better shot at the reeds

Boatman, that's the kind of info I was looking for..........so I will stick to just cleaning and blending the holes themselves.......there's enough work in there. I know that will help by itself. Every single runner has that sharp edge on the way to the reeds and the barrel opening is not consistently smooth.....power to be had

I didn't get much work done on the motor today. I spent some time using my t handles and mic to check the bores in the cylinders. I am not done yet. I have a bore gauge........but my battery was dead. So, I will get a new battery and check again. But it all looks promising. If it checks out, I am going to install new pistons across the board. I found a good deal on some WSM's and will put new slugs in.

I ordered a new hone. I got the Lisle 15000 and a set 280 stones and a set of 500 stones. I finally got a rigid hone....

I did however finish cutting out the reed cages........not complete.........but at least the cut-off wheel work is done. :smiletest: Now I just have to file everything flat(didn't cut it right on the money because of fear of making a whoops!), and then blending the new edges down. The cutting took me about 1.5 hours.........I used the cheap flimsy dremel wheels instead of the fiber ones.......just wanted to use them up.
Then lastly, lap them on my plate and install new reeds. That'll be one part done off my checklist.

I looked again at the intake manifold(on the inside). Man. there is a lot of room for improvement......nuff said.

Pics tomorrow I hope.

Fergot.......motor is completely disassembled now.........all the way down to the water deflectors. I plan on soda blasting the block to get it to bare aluminum. I am gonna need about 20lbs soda( its heading my way). but its worth it. The block comes out beautiful and clean............with no damage to anything. I highly recommend it. You can blast aluminum all day long......it don't hurt it. It gets those ring lands spotless too. The cheapest place I've found for soda............Harbor Freight.........its Arm and Hammer too....not some no name product.

Keith

Mrichartz, I watched a video on the time-sert......awesome stuff. I had never heard of them. Been using heli-coils for years........done with them.

Unless you are porting this engine to make power at 7000 IMO leave all the bridges in the reed block and just clean them up. They will last much longer and flow plenty of air. I have tried more different intake variations than I want to think about, most are a very little help compared to cleaning up stock, a couple did help above 4000 but these were on engines that would turn 8000 RPM and were ported for that. Anything over 6300 hurts reliability a lot and you need to stay away from 64 to 6600. Remember turning an RPM and actually making power at that RPM can be 2 different things. IMO I would not reuse rings, hone and go with new so engine breaks in correctly.

If you want to build a hot rod for a light boat (modified beyond just clean up these engine do not like pushing weight on todays fuel) search on here for OMC 9 pages. It lists what to do but for an everyday application IMO change the port radius to 5/8 or 3/4. Later testing found going under 3/8 only hurt life without any additional power.

Alan, thanks for explaining things about the reeds and the intake questions. As for the rings.........I had already come to that conclusion earlier today when I had my hands in the bores. Truth-be-told, I realized I didn't want 30 year old pistons in there after seeing the scuffing on that one piston. It didn't make sense to me to install a brand new one and the others are very old............even if compression was great and the cylinders are in good shape. SO, I think I am due to get a set of new pistons(rings too) for the engine.

I got a few good things checked off my list today. will bring 'em up when I can take pics tomorrow and talk about it then.

I will talk about this one though. I got the reed cages all reworked and lapped. I will take pictures of that and post it. I did end up cutting out the 1st and 3rd cage fingers. Let me explain.

After reading Racer's post, I thought about it. He's right about the reed cages. I was too blinded by wanting more airflow. The 2.6 xp had fiberglass reeds with stock cages..........and it pulled to 6000 plus. SO, in the future, when I do this again, I will use the stock style reeds. I am sure I will do this again, because I have a 150 block, another big bore block, a v4 block and a v4 motor. All of them need boring. I will only buy the factory correct reeds from Chris Carson. I have used his reeds for 3 of my motors now. I love them. He's also a really cool guy to talk to. He bored out my 235 a few years back. He's got my business.

Back to the reeds......so since I had already purchased the reeds AND cut a cage already, I just finished it out. I wasn't going to send the reeds back, throw a cage away and start over(but that is only reason). Those high flowing cages aren't gonna hurt me. It may shorten the lifespan of the cages. I have some spares in a box. But I doubt that I will do it again. They do look nice and they are blended as much as I could. I tapered the entry openings and smoothed out all sharp edges and was very tedious at the nose of the cages to make sure they were smoothed since the air runs past/over that lip.

I looked at the block again while showing it to a friend today. I am gonna port the center ports of every cylinder. I am going to go left-right only with the porting. I am not moving the exhaust port any. I am just going to square them up some in the center ports. I am leaving the edge ports alone. The fangs are coming out the ports also. I am going to stop there. I am not doing any scalloping. But there is a large ridge at the bottom of the cylinder in the intake tract(right where the scalloping would be). I will be removing that ridge entirely to open up the intake more........I will call it unnecessary aluminum. I have soooooooo much clean up to do in the manifold and the intake tract. I would like to have seen how much hp a 150 would have made with just optimizing airflow both in and out of the engine. I know air hates sharp edges...........and the those aforementioned things are full of them. There is definitely some power to be had in this.

3121?
http://www.wiseco.com/ProductDetail....989&AppID=9840

And some decent compression!

How about a bit of funnelling shape on the ex ports sharp edge to the chest. I did a bunch of shaping and area stuffing with aluminum ceramic on a xflow, not OMC. It's definitely helping the signal and dead areas to help the out and in of things. Just a thought for you.

Quote:

---

Originally Posted by FMP

How about a bit of funnelling shape on the ex ports sharp edge to the chest. I did a bunch of shaping and area stuffing with aluminum ceramic on a xflow, not OMC. It's definitely helping the signal and dead areas to help the out and in of things. Just a thought for you.

---

Do you have a pic to show what you are saying? I haven't even brought this up yet, but I do want to work on a couple of spots in the exhaust areas in the filler blocks. Cylinders 2 and 3 get the leftovers in exhaust area, and I want to open them up some, but I don't want to ruin the fillers because they aren't available any more........or if they are............stupid expensive.

Quote:

---

Originally Posted by FMP

3121?
http://www.wiseco.com/ProductDetail....989&AppID=9840

And some decent compression!

---

not sure the direction I'm going yet............but I do like their compression............they made 15-20 more lbs in my v4 than the stock pistons. With tight heads I was seeing 160 with off the shelf parts.......had to run really good gas tho....

The motor I did that to had individual compartments for each cylinder at the ex ports. The corners took the stuffing and some port blending to shape.
The area around the ports on the OMC , the corners around the perimeter of the port area , can't really make the contour out in the pics but looks like some dead areas in spots. It's not just flow but what the pressure signals do in those spots and how they can be made to follow shape to and from the port.
I'm sure someone has tried shaping etc.

Just after milling ports but you notice the outside corners etc , dead areas that took stuffing and blending after surface preparation. Ports were then blended. Individual compartments per cylinder which then has stuffers installed to further transition smooth to the"primaries" of the manifold system.

Thanks for the pics.........gives me ideas with mine for blending.........specifically cylinders 3 and 4.

Reed cages:Attachment 437770Attachment 437771Attachment 437772

Here's my working on a piece that needed a lot of blending down. Definite improvements in airflow on this one!!

Attachment 437773Attachment 437774Attachment 437775

This is how it should've come from the factory. I know its cast..........but make this mold and cast it!! Check out the hard square corners in the stock piece. Its over 1/4" of useless material. It reminded me of porting cylinder heads. You flip it over...and you see another angle to blend down or in.

Keith

I worked the block, adapter to tuner as well. A curve needed work , a drop off 90° that caused lots of short side flow eddies before the tuner to name one.

Ok here's what I was able to work on since I haven't been able to move forward with the block yet. I spoke with my friend on the phone about the block, and I will be working on that very soon. So in the first set I have the velocity stacks b4 and after.

Attachment 437856Attachment 437857Attachment 437858

Here's the rest in random order..........there are the water covers, bubble back cover, t-stat covers and stacks mixed in.Attachment 437859Attachment 437860Attachment 437861Attachment 437862


I want to powder coat the idle passage cover on the carbs too. I wanted to do the starter case, but aren't there magnets epoxied to it? I think the heat will ruin the epoxy. That's all the bling stuff..............or is it.

I got the hone just a few minutes ago. I am excited..........first rigid hone for me and I have heard great things about this one. I am also excited to have the 500 grit stones as a final pass. The hone came with 80 and 180 stone. I bought extra the 280 and 500 stones for it. Metal starts to take on a different sheen after 320...........

Anyways, after talking with my friend. I am gonna hone the cylinders(hopefully tomorrow) and then make my decision about things. I do plan on working on the ports tomorrow and the clean up of the intake tracts and intake manifold...........oh yeah powder coat? yep. Its gonna look good. its functional and looks good too.

I wish my baking soda had showed up by today...................oh well. It would've been nicer porting a clean block versus a sticky greasy one.

I got some help today from my two sons and my wife. I worked on showing them what to do.......so I could get working on the ports and porting and blending. Here's the b4 and after of the intake.Attachment 437896Attachment 437897Attachment 437898Attachment 437899

I didn't have all my supplies with me at the shop to hone. I will do that Monday......Lord willing. I did port the lower area where a crossflow would normally get a scalloped treatment. I ground down the large lip there instead. It is a blockage of the incoming air from the reeds. What happened in the process was that the lower edge of the cylinder was raised about an 1/8 inch. No big deal......if an engine runs fine with the scalloped ports. I blended the whole area around that to be smooth and not hinder airflow. Many thanks to my friend CC about explaining the whole scalloped area and its purpose. Attachment 437900Attachment 437901Attachment 437902 I still will blend the areas a little more. But its 95 percent done. The pics don't show the taper in there.....the factory slope

As you can see in the pics, the huge ridge. there is a taper in the intake area at the bottom. I followed that to the bottom of the cylinder lip and ended up raising the lip about 1/8 inch.

I said in a previous post that I would only port the middle port and leave the others stock............minus removing that fang in the middle. So I will post pre porting and after porting.

Attachment 437904Attachment 437906

The intake ports look huge now. But they really aren't. I blended the aluminum for a smooth entry. The sleeve side is smaller than what you see here. The bridges haven't been changed. I do perceive that through the removal of the fang in the center, the ports did get larger overall by about 3-5% because of the sanding roll.

I will straighten the edges a little more when I go back and port the other side of the motor.

here's the exhaust before and after. I only have completed half of the engine at this point. I show a port pic of the exhaust , by looking thru the intake port as well.Attachment 437908 Attachment 437909Attachment 437910Attachment 437911

As you can see, by just moving left and right with a smaller radius, the port gets significantly larger. That radius is between 3/8 to 1/2 inch.....more towards the 1/2 side. The cartridge roll was 1/2 diameter. So, it may have worn down and been less than 1/2".....that is why I said between 3/8 and 1/2 inch. It probably would be, in reality, 7/16 to 1/2.

Here's what I learned on this go round with porting: this is my 4th time porting a crossflow by hand. I used air tools(burr and sanding rolls) and a rat tail file at the end on the exhaust(2 of the 3). The file is easier and faster. It doesn't chatter or dig too much. There's no whoops! And when you are done........chuck in a sanding roll and make it all blend. I will port the other side this way. I will however, use air tools for the blending at the bottom of the cylinder in the inspection cover area.

Remember now, I still have to hone(maybe bore) and chamfer the ports. I am already aware of certain things. I just haven't mentioned them to save me writing bout them.

The only prob with a rat tail file (for me)...........my hands ache..............oh well:rolleyes:

For what its worth, the piston never goes past the lower edge of the intake port during its travels.....actually the piston is about 1/8 inch above the lower edge of the port. I checked on this before I tore the motor down. So, I don't really see the need to port the lower corners. I did it however, because it made it easier to "see" what I was doing when I was porting. The symmetry help my eyes focus on lines............

Just going by eye, you've raised duration on the transfers as well as area. Do you have a specific number of degrees in mind?

No. My intent wasn't to raise anything......except the area at the bottom of the cylinder on the intake side(which you cant see from the photos). I do believe that things got raised by me smoothing out the hump with a cartridge roll. But if you are looking at it from the outside of the piston looking in, it may not be as raised as it looks. I intentionally chamfered the intake ports to make smooth airflow into the piston......instead of a straight 90 degree turn into the cylinder. But I do believe that the sleeve holes themselves are slightly larger from blending with a cartridge roll......unintentional. I will go back and further tweak things. But the general porting is done......for 1/2 of the motor anyways. I will check the ports with a caliper to make sure that the heights are the same b4 I am done.

I see, the area increase should help some.

If you can for interest, after assembly take a degree wheel measurement of the opening, transfer and exhaust.