JohnRude V-4

[BIG AL]

Can anyone tell me if an 85 horse can make good power?Will the 140 exhaust plate work,what kind of power can be made,what porting needs to be done what carbs,anything else?I would like to get as much as is safe on 91 octane and be reliable.Any ideas......Al

[dan agnew]

you can make any v-4 into any power level with enough work and cubic $$$
the 85 block needs the bosses in exhaust to accept the bubble exhaust filler blocks. the engine needs to be checked that it is a 99 cubic inch engine and not a 90 incher. that would be a 3.5 bore
1 3/8 carbs make best top end power 1 5/16 next. any ignition system ok best to stick with yr your engine is.
port block out to 140 specs i would finger port block possible scallop block and pistons
mill intake to push reeds closer to crank[more crankcase compression] dual stage reeds help
lighten pistons, wrist pins rods
work piston tops and combustion chambers no more than 135 to 140 lbs compression.
have fun done rite with lite boat you can roll hard

Danny

[BenKeith]

Dan,

I've since I've been reading this site I've seen a number of post about finger ports in a cross-flow. How and where would you put finger ports in an OMC cross-flow. The intake ports take up the whole intake runner.

In the past, when I've seen them, I've just written them off as someone that doesn't know what he's talking about. But I don't put you in that catagory, so now you've got me asking. I've always thought squaring the ports, raisning them on some motors and increase the duration was about all you could do to the ports on them.

[dan agnew]

the best place to put em in the cylinder is rite at end of intake port it extends intake around cyl towards ex port. goes down cyl wall towards bottom. if i could get this crappy scanner to work i post a pic or drawing. very simple cut. and it works very well. has a small cooling effect too. looks like your intake ports are sagging down cylinder. also we xperimented with power port above scallop just like a i-6 merc ran. more air in more air out more output.

Danny

[racer]

Dan,

The power port helps almost as much as the finger for power but as you said the finger cools the corner of the piston a lot better.

Alan Stoker

[BIG AL]

Dan/Racer,I hope to hear something on this rig some time this week if the owner gets the paper work in order.
Baja 16 SS with 85hp V-4 if it turns out that it's not 99 ci but the 90ci is there anyhope for hopping it up or will I have to find a 99 ci and go from there.I would really like to build a sleeper with this rig and stay with V-4 power and sure that ya'll can get me there.
Thanks....Al

[Laker]

Your best bet is really to find a late model 115 or 77-84 140 Xflow powerhead and just drop it on. Difference in power is huge over an 89 CID motor.
Nothing really works well with the small blocks as far as hop ups. You can gain alittle power but not that much where you would be happy. Only thing im not sure about is the bolt pattern of the small block v4. It may be like the 135s... Racer or Danny will know for sure.

[BenKeith]

Dan/Racer



Soon I will be rebuilding my 1989 150 XP. Not knowing just how much I could go, I had planned to raise and lower the ports in it so it would have the same timing and duration as my stock 1978 200. Also planned to square the port. It currently has very small ports compared to the 200. I have a set of 78 200 heads I'm going to cut and put on the motor to raise the compression to about 140. Was thinking about adding the 235 exhaust chest and 1 3/8" carbs but not sure if the gain would be worth the extra expense. Was thinking of running a set of Pro Power cast piston, have no idea what a scalloped piston is,

This motor will be a fishing motor on a heavy boat bass boat so I can't get too radical but if I could get a picture of the fingers and power port, I would appreciate it. Adding fingers to a cross-flwo, do you drill the pistons like you do in the loopers?

Will doing all this make a noticable difference? Can I get an extra 30 to 50 hp out of this motor? Don't laugh to hard. I'm not going to turn the motor over 6,000 - 6,200 rpm. Also plan to keep the VRO??? and 35 amp flywheel.

Any words of wisdom wold be appreciated. Something like Al's nine pages would be great.

I know you can do things like change the roof angle of the pistons and cut the side of the dome some but not sure if that would help since I'm not planning on turning huge rpm's.

I just want to get what I can out of this 150 and still have a good reliable fishing motor. Not like this looper I'm bolting together now that might not run more than a few hours, if it runs at all.

[racer]

Ben,

The 150 block will not except the stuffers from the 235 without major work. Port it like the older 200 and run it, a lot of the other mods make top end power but suffer on longevity.

Al

[dan agnew]

ben the 150 will not accept the bubble exhaust unless you got the exhaust block mounting bosses cast in the exhaust cavity. i think you may not want to finger port the engine turning the rpms you plan. finger ports will help cool engine and allow you to use all your timing and good compression. if you port block i would widen ports but not raise much it tends to kill low end power which you will need to launch a heavy bass boat.
we recently converted a gt150,1989 to a 235 bubble exhaust, on a cajun 20 ft hull engine ran very well and he got all he wanted on top end.BUT he carried boat up the lake about 16 miles on the mat ran it hot and stuck piston. just cannot run em at big timing butt load of compression and miles at a time.
look at playing with tuner, pull bucket out, no more than 130 to 140 compression 24 to 26 degrees timing larger carbs plastic reeds and be happy. if not get a looper ,adaptor, and a looper drive shaft. you will love it

Danny

[BenKeith]

Alan, Dan Thanks

It doesn't take much to talk me out of doing many mods this block. I've done so much and spent so much time on this looper I'm sick of it, just want to get it together and on the boat. I'm hoping this will happen in the next couple of weeks, bolted intakes on last night but still have a coule of parts to get. The 150 is my backup motor, I have no faith in the looper living very long.

I knew it took major mods to the block and another adapter to install the 235 exhaust. That's why I was wondering if it was worth the trouble/expense. Sounds like not for my plans.

So, I'm going to port like 200, run 130 compression instead of 140 and back timing up a couple degrees, as per Dans suggestion and leave everything else alone. Staying with 1 5/16 carb, not even going to the 1 3/8". Maybe this will give me 175 to 185 hp anyway. This should give me the same motor as an old 200 with a little more compression. Just want this one to be a good, dependable motor, so don't want to get too radical.

[H2OPERF]

Why no faith in the looper?

[BenKeith]

Other than rings, gaskets and seals that's the only new parts going in it.

The Bearings and rods are out of several different motors

One piston is a used one from Racer where I droped and broke one.

The crank is a used crank I ordered out of Florida.

I've done so much cutting on the block, it may go in a dozen different directions. The crankcase pressure may be different levels of vaccum instead of pressure.

When I had the rods balanced, the caps weren't torqued down on them, so when they ground metal off to lighten them I think the heat made them misalign because I had a heleva time getting them getting the sides lined up.

This is a salt water motor I bought cheap to learn with, now I've learned. If it works ok on my boat, I will problably find another power head and do it right, without so much of the grinding inside. If it doesn't I'll have what's left of a looper motor for sell real cheap. Boats only rated for a 175 anyway.

[FCnLa]

They are suppose to misaline. It takes a special tool from OMC to do this. Or a "C" clamp or something to hold it together so you can torque it. This would be my main concern. I have seen motors thrashed because this was not done properly.

Borrow an OMC factory manual and make some copies of the proceedure. I could do it for you, but am currently out of town.

If you do not have the rods right, it probably will not last more than 5 minutes......:eek:

[BenKeith]

FCnLa,

Let me rephrase the learning part. I was talking about learning about getting more hp out of looper motors. I've built lots of outboard motors and know about the special OMC tool, and could get my hands of one if needed. I have a similar tool I made years ago that does the same thing when needed. It was need badly on three of the rods, the three they had to take the most metal off the caps. The rods are very well alinged now, it just took a whole lot of exra effort and several tries to get them that way. It's just normally, if you pay careful attention when first setting and torquing the caps, a tool is not needed, but not in this case.