Marinizing GM Engines

[FROGMAN524]

How hard would it be to put two of these in a boat?

Site Maintenance

www.chevrolet.com

 

[HST4ME]

Fine once you buy it, take it all apart, do the bearing clearances, redo the whole valvetrain and put a camshaft that doesn't suck water back into the motor, not to mention a bunch of other things.

 

[DarkHorseRacing]

So at a minimum you’d need to swap out the valves for something severe duty, maybe go to a colder plug, and probably have the valve seats replaced.

You’d probably want to make sure the cam is degreed straight up for balanced HP and TQ and maybe go to a beefier cam timing setup.

Then you need to add a water pump into the accessories and get a marinized alternator.

Put a USCG approved flame arrestor on it.

And everything HST4Me said. Cam needs the right lobe separation to avoid water inversion in the exhaust. Loosen up the bearing clearances.

Something else I forgot. Get a cast iron gear for the cam and then you have to melonize the gear on the distributor (probably swap with an MSD unit). Change the ignition out to MSD with a rev limiter.

Larger capacity oil pan, take the oil pump out and set the pressure higher.

 

[mash on it]

The engine doesn't know it's in a boat.
V-drive. Or jet.
Dry headers.
Done.

Dan'l

 

[Racey]

The engine doesn't know it's in a boat.
V-drive. Or jet.
Dry headers.
Done.

Dan'l

Lol tell that to the guys that bought GM 572s and put them in boats only to end up spending twice

 

[Tank]

Yeah. Jeff Cheng put a couple 572 crates in his gladiator many years ago. Blew a motor pretty quickly. Something about clearances to close valve sticking. Rebuilt them and changed a bunch of stuff like listed above also the carbs aren’t marine rates so they need to be changed too. He spent a lot of money - 20k a side I believe and this was in 2005. Ended up yanking hem because even after all that they still had issues.

They were purdy though.

 

[spectras only]

dug up my old thread on the ZZ572 engine marine conversion. Boy oh boy, that was a few years back.
BTW, the engine is still in the boat with probably well over 6/700 hrs, it was a commuter for my friend between Vancouver and Vancouver Island. Just saw my buddy listing it for sale first time in 2022 on craigslist. It was a cool project and we had fun attending poker runs with it. The life raft holding compartment actually is a functional hot tub, running on propane heat. I'll get the video off of YT.
Here's my post with info on some changes in the engine.

Scratch built 33' single engined boat by Craig

My friend Craig started this project while working at Sovereign [ now Richmondyachts ] shipyard about 4 years ago . He built the mold incorporating steps to make the boat to be able to get on plane with a single engine with a thought of good economy . The boat is foam cored achieving a goal...

www.riverdavesplace.com

My Son and Craig

Maiden voyage

We were clocked by the floatplane at our Sidney Poker Run

 

[spectras only]

The hot tub with the propane unit up front above the 100 gal ballast tank in the locker.

BTW, Chris Davidson was on this boat with us along with his film crew. Don't know what happened to the video, never seen it.
He attended the Harrison Lake Poker run with us. How is he doing, anyone know or keep in touch with him?

 

[LargeOrangeFont]

The engine doesn't know it's in a boat.
V-drive. Or jet.
Dry headers.
Done.

Dan'l

This guy gets it

 

[obnoxious001]

This guy gets it

Not really. There are differences running an engine in a boat, primarily block temperature never gets up to automotive running temps without a thermostat setup, and operating RPM's are continuously much higher in a boat, similar to a race engine.

 

[LargeOrangeFont]

Not really. There are differences running an engine in a boat, primarily block temperature never gets up to automotive running temps without a thermostat setup, and operating RPM's are continuously much higher in a boat, similar to a race engine.

Agreed. Temp control is key to making it work.

Look at the marine LS3s and LSAs.. they are long blocks off the assembly line, and they want you running 5w30 oil in them.

Of course they are supposed run closed cooling for temp control with those engines.

 

[Gelcoater]

Not really. There are differences running an engine in a boat, primarily block temperature never gets up to automotive running temps without a thermostat setup, and operating RPM's are continuously much higher in a boat, similar to a race engine.

Isn’t LSA pretty important if running water cooled exhaust?
114 sticks out in my mind.

 

[fat rat]

The engine doesn't know it's in a boat.
V-drive. Or jet.
Dry headers.
Done.

Dan'l

I ran a GM 502/502 crate for years in a jet boat, guessing 6-7 years. Ran the shit out , my final run was just over 30 minutes at 5500 rpm without an issue. Sold the boat the guy ran it for another 3-4 years, no issues.

 

[Teague_JR]

I’m less interested in the engine as a whole for boats and more interested in the new heads that they designed. As soon as you can buy them bare it would be a lot of fun to play with them. They are essentially a mix between a massive BBC 12 deg setup with stuff they learned from the LS engine. It’s a completely symmetrical port big nasty flow piece but without offset rockers and much more efficient chambers. The intake ports are so high up they can run a separate aluminum valley tray to insulate the intake from oil and coolant. That’s where they stuck the coils on the zz632 (like a viper motor)

Anyways, some other interesting tidbits: they are running hydraulic roller on a 780 lift (1.8 rocker ratio) 270/287 duration big ass cam. Giant 2.450 intake valve but only 1.800 exhaust and 5/16 stems. Might want bigger exhaust valves and 11/32 stems for forced induction but then you get back into more weight and breaking valvetrain parts. Only 70cc chamber size I’m assuming because they have the valves so flat to the piston (standard bbc open chamber is 118 to 124 these days).

As far as the bottom of the motor it’s all high end parts. It would be interesting to see if it would detonate with that 12:1 compression at 6000 rpm steady state with cooler engine water. You would want to check what they clearance the motor at and run oil thermostats. Conversion to a dry sump would be a good idea. I’m thinking the chamber design is allowing higher compression in pump gas or their engine controller is super dialed into knock detection. That can also not work in a boat as it thinks propeller harmonics are knock.

This engine is the biggest advancement in the bbc platform from an oem perspective in decades. I read that they were developing this head in the 90’s and it got shelved. When they brought the project back and started Dyno testing the final combo, they redid the intake port with CFD modeling but the original hand done design was actually better in the real world.

 

[spectras only]

We had a oil cooler/filter combo with thermostat and safety shut off in case temp spike. Never had overheating. We also added temp sensor/gauge in the B1 X drive.
The Dooley pan was a kick out pan style as well to keep the 14 QT oil where it's suppose to be, while in sharp turns. I'm wondering if this new ZZ632 engine has piston oil squirters like the LSA marine engine?
I've checked bottom end [ it was 0.0025 ] and rod bearing [ 0.002 ] clearances before installing the engine in the boat, also the bronze valve stems. We took time not to go gong ho on the throttle for 20 hrs, before any WOT.

 

[mjc]

I’m less interested in the engine as a whole for boats and more interested in the new heads that they designed. As soon as you can buy them bare it would be a lot of fun to play with them. They are essentially a mix between a massive BBC 12 deg setup with stuff they learned from the LS engine. It’s a completely symmetrical port big nasty flow piece but without offset rockers and much more efficient chambers. The intake ports are so high up they can run a separate aluminum valley tray to insulate the intake from oil and coolant. That’s where they stuck the coils on the zz632 (like a viper motor)

Anyways, some other interesting tidbits: they are running hydraulic roller on a 780 lift (1.8 rocker ratio) 270/287 duration big ass cam. Giant 2.450 intake valve but only 1.800 exhaust and 5/16 stems. Might want bigger exhaust valves and 11/32 stems for forced induction but then you get back into more weight and breaking valvetrain parts. Only 70cc chamber size I’m assuming because they have the valves so flat to the piston (standard bbc open chamber is 118 to 124 these days).

As far as the bottom of the motor it’s all high end parts. It would be interesting to see if it would detonate with that 12:1 compression at 6000 rpm steady state with cooler engine water. You would want to check what they clearance the motor at and run oil thermostats. Conversion to a dry sump would be a good idea. I’m thinking the chamber design is allowing higher compression in pump gas or their engine controller is super dialed into knock detection. That can also not work in a boat as it thinks propeller harmonics are knock.

This engine is the biggest advancement in the bbc platform from an oem perspective in decades. I read that they were developing this head in the 90’s and it got shelved. When they brought the project back and started Dyno testing the final combo, they redid the intake port with CFD modeling but the original hand done design was actually better in the real world.

The head is basicly an Olds DRCE cyclinder head. I think prostock still uses some of them