Boat motor

[Broncobowsher]

It does look like a fresh build. Head studs are a nice upgrade as well.
But I do question the bolt in expansion plugs at the motor mount. Marine install are usually brass, sometimes stainless. Those plugs are usually in car repairs where you can't get to the plugs very well.

 

[DirtDonk]

The intake doesn’t look super tall, but also does not look like it has a boss for a heater hose. Looks like there are spacers under the carburetor that give some extra height.

 

[joshua]

It does look like a fresh build. Head studs are a nice upgrade as well.
But I do question the bolt in expansion plugs at the motor mount. Marine install are usually brass, sometimes stainless. Those plugs are usually in car repairs where you can't get to the plugs very well.

Ya I thought the same thing.

 

[joshua]

The intake doesn’t look super tall, but also does not look like it has a boss for a heater hose. Looks like there are spacers under the carburetor that give some extra height.

There is a spacer. Not planning on using it.

 

[brewchief]

For 500$ I think you did really good, I bet the boat exhaust manifolds and accessory setup will sell and recoup some or all of your investment. Are those aluminum heads? If so is there a brand and part number on them?

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[joshua]

For 500$ I think you did really good, I bet the boat exhaust manifolds and accessory setup will sell and recoup some or all of your investment. Are those aluminum heads? If so is there a brand and part number on them?

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They are aluminum. And I don’t see any markings. Some of the fresh paint chipped and the aluminum looks brand new.

 

[joshua]

Only thing I see is 14204 probably knock offs is my guess.

 

[bmc69]

Holy smokes. There is almost nothing "original, marine" in that build except maybe some of the short block assembly. Even Holman Moody performance marine engines barely reached that level of build. When you started this thread about a "boat engine", I assumed it was still in a stock-ish marine engine form. Not even close.

 

[joshua]

Holy smokes. There is almost nothing "original, marine" in that build except maybe some of the short block assembly. Even Holman Moody performance marine engines barely reached that level of build. When you started this thread about a "boat engine", I assumed it was still in a stock-ish marine engine form. Not even close.

Well I did as well

 

[gnpenning]

Looks like you did well. For the price of a few gaskets I would pop off the front and look for cam information. Pretty easy to do now, plus you shouldn't have to worry about frozen bolts.

Might even take a peek through a plug hole and see what they did with the pistons. Do you or anyone you know have a borescope?

 

[bmc69]

Well I did as well

What I see in those pics more resembles this 302,custom built for a 1972 16' Donzi, than any stock marine engine...

 

[71 CA Bronco]

Those freeze plugs raised my eyebrows as well. I would still tear it down to be sure it will work for your application. Many marine engines have looser tolerances than automotive. I believe this is to accomadate the cooler temps running through the block with raw water cooling. You should also check the water passages closely. If it had raw water cooling, or salt water use, the rust and debris build up (not to mention metal wall loss) can be hard to deal with. Pulling those freeze plugs should give you an indication of previous use..

 

[joshua]

Looks like you did well. For the price of a few gaskets I would pop off the front and look for cam information. Pretty easy to do now, plus you shouldn't have to worry about frozen bolts.

Might even take a peek through a plug hole and see what they did with the pistons. Do you or anyone you know have a borescope?

I think I have to change out the timing cover anyway

 

[joshua]

Those freeze plugs raised my eyebrows as well. I would still tear it down to be sure it will work for your application. Many marine engines have looser tolerances than automotive. I believe this is to accomadate the cooler temps running through the block with raw water cooling. You should also check the water passages closely. If it had raw water cooling, or salt water use, the rust and debris build up (not to mention metal wall loss) can be hard to deal with. Pulling those freeze plugs should give you an indication of previous use..

What would looser tolerances cause??? I guess I didn’t see anything on that when searching marine vs automobile

 

[Broncobowsher]

That is a raw water cooled boat motor. That giant pulley on the driver's side head is the raw water pump. Goes into the thermostat housing. The big hose around the alternator is the circulation hose. When the engine is cold the raw water is bypassed and goes to cool the exhaust manifolds.

Marine engines typically have looser piston and rings. Cold raw water cooled cylinder walls are smaller. Pistons running at full song for extended periods of time run hot and expand. In a boat application that results in a happy engine. On the street it generally isn't bad. Just a little tiny bit of floppy piston, touch more blow by. Little less life. Better than the other way around. Don't want a piston or ring to bind up in a cold cylinder. The opposite is an F1 engine that is so tight that they are seized when cold and have to be pre-heated just to start them.

 

[joshua]

That is a raw water cooled boat motor. That giant pulley on the driver's side head is the raw water pump. Goes into the thermostat housing. The big hose around the alternator is the circulation hose. When the engine is cold the raw water is bypassed and goes to cool the exhaust manifolds.

Marine engines typically have looser piston and rings. Cold raw water cooled cylinder walls are smaller. Pistons running at full song for extended periods of time run hot and expand. In a boat application that results in a happy engine. On the street it generally isn't bad. Just a little tiny bit of floppy piston, touch more blow by. Little less life. Better than the other way around. Don't want a piston or ring to bind up in a cold cylinder. The opposite is an F1 engine that is so tight that they are seized when cold and have to be pre-heated just to start them.

This will be far from a daily. But I would like to be “reliable” I think I want to ditch this carb and order a sniper set up. I would just run the carb for now. But it’s brand new and would rather sell it than just use the carb for a short while. But now I’m kinda worried on these rings. I’ll have to do some more research I guess.

 

[71 CA Bronco]

I'm sure someone here knows more about this issue than I, but during my brief history running an offshore race boat, I met more than a few people that tried GM crate engines only to have them seize up shortly after install. I have never heard of the issue doing it the other way around, ie taking a loose boat engine and putting it in a car. I knew a few guys that took car engines with a bunch of miles on them and put em in boats with no issues. The theory being the high miles put on the car engine loosened the tolerances a bit before being re-purposed in a boat. Not sure how good my advise is though given I actually have more experience blowing up boat engines than making them last. Its a test of a marriage $$$$.

 

[bmc69]

This will be far from a daily. But I would like to be “reliable” I think I want to ditch this carb and order a sniper set up. I would just run the carb for now. But it’s brand new and would rather sell it than just use the carb for a short while. But now I’m kinda worried on these rings. I’ll have to do some more research I guess.

Having built/rebuilt many marine engines, I don't recall once using a different tolerance on bearing clearances or piston clearances simply because it was a marine engine. I have varied those tolerances on very high performance engines in general, but I'm not aware of any fundamental differences in the way Ford, GM or Chrysler assembled the millions of engines they sold for marine use. I'm currently building a pair of twin-turbo Ford 534s (Seamasters) for a boat and have an original tech manual from Ford. It's the exact same one they provided for the 534 Super Duty truck engines. A lot of what I see posted about "marine engines" is myth, not fact. Probably the single most common "feature" distinguishing a typical marine V8 from its highway cousins is the addition of an oil cooler and increased oil capacity.

 

[Broncobowsher]

I would not be surprised that they are the same specs as the HD truck engines. Especially if running a coolant loop. Those engines are also designed to run sustained full power.

I have ads of the Ford Interceptor marine engines, a division of the Ford industrial engines.

 

[71 CA Bronco]

Like BMC69 said, I would think this has a lot to do with the intended purpose of the motor. I just did an internet search on the issue and it seems high performance/race boat applications and/or raw water cooled engines tend to have a bigger issue with tighter tolerances and crate/car engines seizing up. I'm guessing a low reving engine and/or closed loop cooling engine would not have the same issues. This is a good topic to discuss though. I have always wanted to try crate motors in a boat but have hesitated due to the ones I have seen scatterd.

https://www.boattrader.com/resources/inboard-boat-engines-car-engines/