School me on OMC V8 Outboards

[Instigator]

I learned that right here on S&F!

An oven works better but it will stink up the house for days!

Ask me how I know.

Its actually one of the strong attractions for me, to the OMCs for hot rodding.

Some of us don’t have the budget to support a high end nic 2.5 motor so this works.

I can pop an OMC, assuming no holes, and replace a sleeve, piston/rings and a rod (free from my parts supply) for $300. ($200 if I reuse gaskets which I do a lot) and be back on the water the same day if I thrash.

And have brats on the already hot grill!

PS, I will argue the benefits of chrome/nic w/anyone that wants ��

[NoLimits]

So from what I understand, the pistons/rings/rods/sleeves/reeds/carbs on the v8 are all shared with the v4/v6, and the real hard to find part is the crank. I'm slowly tearing mine down, not sure if the crank is good or not yet.

I'm aware of Monty, but it's getting kind of tiring wanting to learn about these things, and having everyone say just send it to Monty. I want to learn.

So the race version isn't based on the production version? Was it just thicker sleeves/smaller pistons to reduce rotating mass so you could spool it up faster?

What kind of hot rodding tricks can be done to them? Has anyone attempted EFI with Megasquirt or the like?

[racer]

1985 V8 had different reeds, intake manifold, carbs. Sleeves are different (porting) Early V4 had different reeds between the 120 and 140. 1988 all went to a larger bore and slightly shorter sleeve with the V6 going to oval instead of bridged exhaust port. 1993 the V6 got finger ports with a smaller exhaust port. 4 different intake manifolds depending on year. Race version is a totally different block with a shorter stroke crank with smaller rod journals, intake, piston design, removable exhaust chest and more. Yes several of us have installed efi but unless you get one preprogramed you may burn one down a few times before getting it mapped right, having a dyno helps a lot.

[LakeFever]

1985 V8 had different reeds, intake manifold, carbs. Sleeves are different (porting) Early V4 had different reeds between the 120 and 140. 1988 all went to a larger bore and slightly shorter sleeve with the V6 going to oval instead of bridged exhaust port. 1993 the V6 got finger ports with a smaller exhaust port. 4 different intake manifolds depending on year. Race version is a totally different block with a shorter stroke crank with smaller rod journals, intake, piston design, removable exhaust chest and more. Yes several of us have installed efi but unless you get one preprogramed you may burn one down a few times before getting it mapped right, having a dyno helps a lot.

wow. Your library of omc knowledge is unreal

[Instigator]

Thank you Al.

A guy comes on here expecting to get cam shaft part numbers and read 3 paragraphs on how to build a motor that barely exists??

Good luck dude.

You came to the best place on the planet for help and that ain’t how it’s done.

1985 V8 had different reeds, intake manifold, carbs. Sleeves are different (porting) Early V4 had different reeds between the 120 and 140. 1988 all went to a larger bore and slightly shorter sleeve with the V6 going to oval instead of bridged exhaust port. 1993 the V6 got finger ports with a smaller exhaust port. 4 different intake manifolds depending on year. Race version is a totally different block with a shorter stroke crank with smaller rod journals, intake, piston design, removable exhaust chest and more. Yes several of us have installed efi but unless you get one preprogramed you may burn one down a few times before getting it mapped right, having a dyno helps a lot.

[NoLimits]

Dude WTF is your problem? When did I say that?

I'm wanting to learn as much as possible and I'm not finding ANYTHING with google searches other than 'talk to Monty and have him do everything for you'

[Greg G]

So there is not a website or general FAQ about them anywhere?

No nothing like that was ever put together.

[Greg G]

And many of the folks with the knowledge required to do so have passed away.

[LakeFever]

FWIW I didn’t suggest you simply throw money at Monty and call it a day. I did say he’s the best one who knows the right info for working with V8 omc motors in particular. He builds all kinds of wicked omc stuff but the V8 is niche and he’s the man. Surely worth a phone call to pick his brain and at least get set out on the right path. This is a no brainer to me. As with above most of the guys who worked on these motors are quite old now or sadly no longer here as mentioned. Not all that much omc Activity here the past few years

[Instigator]

Here’s your challenge:

1. EVERYTHING you are looking for is on this website!
But, the search function sucks!

So I don’t even know how to find my own, old posts??

2. Writing a check to Monty, which I understand is not your intent, still ain’t all of it.

A high strung two stroke OB is very high strung requires tons of maint/$$$.

Think, 5’8” blue eyes, blond hair, big……, well, you get it.

Merc, OMC both.
It don’t matter.

W/a Merc, if you have problems, there’s tons of people to help you.

A V-8 JohnRude?
Theres only a few of us w/much experience/help and although very similar, 99% of mine is on the V-6’s excep this one I just started.

3. And my smart ass response about the camshaft part # was a hint at the difference between what you are wanting to do Vs, building an LS series motor.

There are 1000’s of recipes, complete w/part #’s ……, that tell you how to build a 1000 HP pump gas motor.

4. Calling Monty and asking for (free) help.
I have done it.

But understand you are taking time out of his day to coach you on a project that he will likely never make a dime off of.

5. W/a hot rod 2 stroke, it’s all about porting.
That you can’t learn from a book.

It takes hrs, hrs, and hrs of experience to know how to do it, where to do it, how big to go, port heights, port angles, plus $100’s of dollars of carbide burrs, a good die grinder and a healthy compressor to power it.

And one slip w/grinder can destroy hrs and hrs of work and a good block.
Ask me how I know.

6. You’re for scavenging 40+ yr old parts from who knows where, zero over counter stuff available, etc and many of the sellers know zero about what they’re selling.

7. I’m 66 yrs old and have been doing this for 30 yrs.
I have helped dozens and dozens of people and 99% of them, listen to 50% what I tell them, make x that in w/their auto mechanic friends and their motor pops before it’s broke in and they have no clue why.

Normally they do it one or more times before giving up, buying a hot rod Merc ( that was hot rod from the factory), tons of parts, tons of help and climbing on the OMC sucks band wagon.

One guy I helped, bragged about how fast h could change a piston instead of figuring out why it kept happening.

Oh yeah, then switched to Merc while bashing OMCs.

So you asked, what the fk?

Howd I do?

PS, it took me 20 mins to type that!

PS,PS, the motor in the pic is a combination of at least 4 motors.

[FUJIMO]

...i see a couple merc parts on that thing gator. so should haul ass...(lol)......

[Instigator]

Nope.
All OMC!

For now anyhow.

...i see a couple merc parts on that thing gator. so should haul ass...(lol)......

[CUDA]

I've known Monty 30 some years, He's as solid as a ROCK

https://www.facebook.com/p/Monty-Rac...0063652539739/

I recently took him a 90 HP Yamaha to build, I didn't ask for a price and told him no hurry, it's next years project, new finger ported pistons etc.

If you saw one of his V 8 race motors blocks you would be amazed how much work he puts into making one

The area where the intake ports are, is cut open, I never asked how the cutting is preformed but it's a large area outside each intake port area

So after what ever porting is accomplished he has to weld it back together, it's around 3x3 inches square

Monty has had his own line of Pistons made, I believe by Wiseco .

Gordon raced a V 8 Unlimited Mirage back in the 90's when I first meet him through Patrick Eves who was the factory OMC service rep for Florida, Eves was my Factory rep who helped me out with parts, like a free powerhead, he warrantied a race motor once NY factory service rep before moving to Florida as i did, mid 80's

Patrick Eves drag raced himself and drew me back into racing after a terrible accident in 85

People tell you to call Gordon because he's the GOAT, and willing to talk...

Just being interested in OMC's he'll be happy to answer your questions with REAL GOOD answers

He's the ONLY person that has made a living modifying OMC's from 3 cylinder SST60's to V8s

The amount of time Monty spends to make a race V 8 is no where near the price he charges, I believe it's $8,500.00

It would be prohibitive to charge per hour because the price would be soo high.

Monty is still drag racing a V6 OMC, and winning

https://youtu.be/GpS7U3UyyRo



Those F1 motors that they used in the early 80's ran higher RPMs

You had a big motor on a light race boat, you didn't need

Gobs of Torque

I'm not sure of his final cubic inches but it's high,

and they stay together ! in the old days they were not known for reliability in race form

Monty worked that out, with pistons and porting design

So Gordon goes the opposite from the 80's F1 motors

Torque Monsters

https://images.app.goo.gl/Z6aYaPAjQfnwQ52C7

[Instigator]

When we lived over by him I’d go have lunch with him and Chaz once a month and then go snoop through a through his shop.

I always joked that he patted me down for cameras before letting him in though :-)

I think he may be closer to 40 K for a full race V8 though.

When we first moved down there that time he was so slow that he worked part time at the airport to help keep the doors open.

And then he helped some guys start winning with his loopers and his business exploded, and he may be set for the rest of his life from what I see!

[Chaz]

I miss those lunch's ....

Sum Merk parts ..





The guy who made these tiller/ pin/ yoke's had to be sick in the head ...