Converting auto engine to marine application???

[sirbob]

I’ve been looking for an engine to use in a project I have in mind. I’ve seen some decent deals on an automotive engine that has caught my eye for what I have in mind.

What challenges are there in taking an auto application and converting it into a Marine engine.

I’m thinking of a V8 that you would typically see in a boat.

Is this a conversion for any of the usual suspects that work on boats or possibly a specialty shop that does this?

 

[BassLakeCruiser]

Pan, water pump, clearances potentially, cam potentially

 

[spectra3279]

Brass freeze plugs.

 

[wet hull]

Really just the gapping of piston rings, and marine rated accessories. Spring tension can be different if you choose.

 

[LargeOrangeFont]

The LS based marine engine long blocks are right off the automotive line. With an engine like that you need to control oil temp... meaning it needs to be 150 F+ because that is what the clearances were set up for.

 

[coolchange]

Depending on app could be some piston to wall clearance.

 

[bocco]

I would love to do a 500 inch Eldorado motor.

 

[Runs2rch]

The LS based marine engine long blocks are right off the automotive line. With an engine like that you need to control oil temp... meaning it needs to be 150 F+ because that is what the clearances were set up for.

All the Mercury 350's were right off the line. 260 and 290hp GM crate motors.

 

[coolchange]

I would love to do a 500 inch Eldorado motor.

Cool motors make a ton of torque. Expensive to build. Brother has one in a c10.
Was a jet boat back in the day.
FLASH CADILLAC was really nice.

 

[mash on it]

"The engine doesn't know it's in a böté" -GN7

What type of drive might make a difference in your choice of car-bote-motas.

Dan'l

 

[Shlbyntro]

All the Mercury 350's were right off the line. 260 and 290hp GM crate motors.

*and an RV/Marine cam*

the main differences are the cooling system, ignition protected electrical components, and if its carbureted there are also marine grade fuel system components that you will need. *Most* of the fuel injected applications are the same fuel system components.

almost all the differences are in the name of safety, not for any performance related stuff.

 

[sintax]

The LS based marine engine long blocks are right off the automotive line. With an engine like that you need to control oil temp... meaning it needs to be 150 F+ because that is what the clearances were set up for.

LS based marine engines are also closed cooling, I would not deviate from that.

 

[Shlbyntro]

LS based marine engines are also closed cooling, I would not deviate from that.

i wouldnt run raw water on anything with aluminum. recipe for disaster.

 

[92562]

Make sure to use a brushless alternator.

 

[LargeOrangeFont]

LS based marine engines are also closed cooling, I would not deviate from that.

For sure!

 

[monkeyswrench]

Depending on the donor, as well as the hull, exhaust ports may come into play. Some of the more modern things have a flange area facing nearly vertical. Then there is also manifold clearance, or fabrication of wet or dry headers. Depending on the motor, turbo placement and piping.

My buddy has a G35, tuned and ricky-raced...thought it would be a hell of a motor. Twin turbo, little V6, almost 500hp to the wheels

 

[sonicss31]

Another question to ask yourself, is this going to be a cruiser type boat or high performance use? With that known many things will come into play.

 

[Rajobigguy]

It depends on what engine your talking about. If it is running forged pistons you need to add .002-.003 extra clearance in a marine application. That is particularly critical if you have an open cooling system.

 

[sirbob]

Ok

Here’s the scenario.

I buy a Maserati V8 salvage - around $8-10 from a totaled sedan.

And put it in a MOM hull with a wood deck

Just for cruising sunsets...

 

[Orange Juice]

The LS based marine engine long blocks are right off the automotive line. With an engine like that you need to control oil temp... meaning it needs to be 150 F+ because that is what the clearances were set up for.

Are you saying the LS engine will need to be closeloop, with a heat exchanger?

 

[LargeOrangeFont]

Are you saying the LS engine will need to be closeloop, with a heat exchanger?

Yes. It designed to run at 200+ degree fluid temps. You at least need to see 160 degree fluid temps, ideally you want the oil higher than that to burn off any condensation.

 

[Shlbyntro]

Ok

Here’s the scenario.

I buy a Maserati V8 salvage - around $8-10 from a totaled sedan.

And put it in a MOM hull with a wood deck

Just for cruising sunsets...

closed cooling is a must. you will need a standalone computer system if it is not so already equipped. newer engines are designed to sustain higher rpms already. your biggest issue is going to be the mechanical hardware neccesary to couple it to the drive system. hopefully the engine was made in an option that used a flywheel and not a flex plate because you will need one of those.

Its not impossible but it will be an expensive endeavor unless you own your own machine shop

Are you saying the LS engine will need to be closeloop, with a heat exchanger?

yes. unless youre running the truck version thats made out of all iron (which is what most boat LSs already are)

 

[LargeOrangeFont]

Ok

Here’s the scenario.

I buy a Maserati V8 salvage - around $8-10 from a totaled sedan.

And put it in a MOM hull with a wood deck

Just for cruising sunsets...

That sounds cool. I'd have questions about what a flat plane crank was going to feel like hard mounted in a boat though. And will the engine live bolted to a drive.

 

[old rigger]

I would love to do a 500 inch Eldorado motor.

Back in the day Nicson made exhaust manifolds for the 472/500. I missed a set at the Long Beach swap meet by 45 seconds about 15 years ago. Another company, Cad500 or the other one who's name I can't think of right now, made adapters to run 460 Ford manifolds on the 500.

I always wanted to do that too, run the big torque pig in a jet. Next jet for me, probably the last one, will be LS powered though. Already have manifolds for that one...that's all I have though.

Mom had an Eldorado when I was a kid. Use to take it out and drag race my friend driving his mom's Buick. Both cars ran pretty hard to our 16 year old brains but I remember that Cad would fry the front tires as long as you'd keep your foot stuffed in it. Poor dad changing those CV joints, cussing them out for not lasting as long as he thought they should.

 

[JUSTWANNARACE]

Back in the day Nicson made exhaust manifolds for the 472/500. I missed a set at the Long Beach swap meet by 45 seconds about 15 years ago. Another company, Cad500 or the other one who's name I can't think of right now, made adapters to run 460 Ford manifolds on the 500.

I always wanted to do that too, run the big torque pig in a jet. Next jet for me, probably the last one, will be LS powered though. Already have manifolds for that one...that's all I have though.

Mom had an Eldorado when I was a kid. Use to take it out and drag race my friend driving his mom's Buick. Both cars ran pretty hard to our 16 year old brains but I remember that Cad would fry the front tires as long as you'd keep your foot stuffed in it. Poor dad changing those CV joints, cussing them out for not lasting as long as he thought they should.

I have a buddy that has 2 eldarados with 500s in his yard. Been there as long as I can remember. Pretty much just lawn art now. I'll get a few pics next time I'm in coos bay.

 

[oldschool]

Ok

Here’s the scenario.

I buy a Maserati V8 salvage - around $8-10 from a totaled sedan.

And put it in a MOM hull with a wood deck

Just for cruising sunsets...

Just be sure to consult with 2FF on retuning it.

 

[obnoxious001]

It depends on what engine your talking about. If it is running forged pistons you need to add .002-.003 extra clearance in a marine application. That is particularly critical if you have an open cooling system.

That's considerably more than what is normally done unless it's a force induction application.

 

[obnoxious001]

I’ve been looking for an engine to use in a project I have in mind. I’ve seen some decent deals on an automotive engine that has caught my eye for what I have in mind.

What challenges are there in taking an auto application and converting it into a Marine engine.

I’m thinking of a V8 that you would typically see in a boat.

Is this a conversion for any of the usual suspects that work on boats or possibly a specialty shop that does this?

This may have been easier for engine builders to spot if it was placed in the engine section. Main differences would be bearing clearances, piston to wall clearance, ring gap. Camshaft selection is critical if you run exhaust that can get water back up in it. Oil pan and a high volume pump would normally be on my list.

 

[lbhsbz]

Ok

Here’s the scenario.

I buy a Maserati V8 salvage - around $8-10 from a totaled sedan.

And put it in a MOM hull with a wood deck

Just for cruising sunsets...

Remove stock exhaust, add over transom headers.

Run it

 

[LargeOrangeFont]

This may have been easier for engine builders to spot if it was placed in the engine section. Main differences would be bearing clearances, piston to wall clearance, ring gap. Camshaft selection is critical if you run exhaust that can get water back up in it. Oil pan and a high volume pump would normally be on my list.

Would it be fair to say that generally the cam(s) out of a modern emissions controlled is/are "safe" for a wet exhaust since there is little overlap?

 

[sirbob]

Would it be fair to say that generally the cam(s) out of a modern emissions controlled is/are "safe" for a wet exhaust since there is little overlap?

While I have no input on the water / exhaust etc impact. I have looked at the torque curve of the Maserati V-8 versus a mercury 8.2 HO. The general difference is pretty obvious and to be expected, the Maserati generates a little higher torque at higher RPM and the mercury generates higher torque at a lower RPM.

That in itself made me consider tweaking the cam little bit if I went with a Maserati.

 

[obnoxious001]

Would it be fair to say that generally the cam(s) out of a modern emissions controlled is/are "safe" for a wet exhaust since there is little overlap?

I would like to see duration specs at .050" before I made a blanket comment, but most factory street cams are usually shorter duration.

 

[LargeOrangeFont]

While I have no input on the water / exhaust etc impact. I have looked at the torque curve of the Maserati V-8 versus a mercury 8.2 HO. The general difference is pretty obvious and to be expected, the Maserati generates a little higher torque at higher RPM and the mercury generates higher torque at a lower RPM.

That in itself made me consider tweaking the cam little bit if I went with a Maserati.

I would think you'd have to, as you are down 3.5 L. You'd need the 1.65:1 drive as well.

 

[gqchris]

While I have no input on the water / exhaust etc impact. I have looked at the torque curve of the Maserati V-8 versus a mercury 8.2 HO. The general difference is pretty obvious and to be expected, the Maserati generates a little higher torque at higher RPM and the mercury generates higher torque at a lower RPM.

That in itself made me consider tweaking the cam little bit if I went with a Maserati.

I have a GranTurismo. You are welcome to come look at my motor and poke around if needed. I love the car, and its been the most reliable exotic I have ever owned! Cool idea in my opinion, and remember the Massi F136 V8 is Ferrari Built and loves the revs!. https://en.wikipedia.org/wiki/Ferrari_F136_engine#:~:text=The F136, commonly known as,445 kW; 597 hp).

I think that number is high for a used one. JR Garage got one for 3500$ just a few weeks back.

 

[cakemoto]

Motorhome motors with 100,000 miles work good.

 

[traquer]

Italian + boat doesn't sound cheap! but it sure sounds sexy!

 

[sirbob]

I have a GranTurismo. You are welcome to come look at my motor and poke around if needed. I love the car, and its been the most reliable exotic I have ever owned! Cool idea in my opinion, and remember the Massi F136 V8 is Ferrari Built and loves the revs!. https://en.wikipedia.org/wiki/Ferrari_F136_engine#:~:text=The F136, commonly known as,445 kW; 597 hp).

I think that number is high for a used one. JR Garage got one for 3500$ just a few weeks back.

Thanks for the offer to check yours out - I’ve had a couple myself and have a very close friend who runs the Ferrari challenge cars for three dealerships, so I have access to the engines and the talent to rebuild modify etc.

I just love that engine!

I don’t think it’s a good option for a deck boat or a heavy big V but I feel like it would be fun in a small light weight hull like that little FC from MOM.

 

[Chili Palmer]

Has anyone ever done the Corvette n/a 7.0 Z06 engine in a boat? Small block with 500 hp/ 500 tq sounds like a win/win.
Even the C7 Corvette/Cadillac CTS-V LT4 supercharged 6.2 with 650/650 sounds like a winner also.

 

[coolchange]

What’s a MOM ?
What’s the upside to this combo? Being unique?

 

[sirbob]

What’s a MOM ?
What’s the upside to this combo? Being unique?

The little hull that Maxed Out Marine is selling - it used to be DCM and before that...???

 

[sintax]

Italian + boat doesn't sound cheap! but it sure sounds sexy!

You are correct on both parts of that statement.

 

[MK1MOD0]

You are correct on both parts of that statement.

View attachment 1106201

My favorite boat at desert storm last year. Too cool!

 

[sirbob]

You are correct on both parts of that statement.

View attachment 1106201

Not gonna lie - when I saw that boat I was bummed. I felt like someone executed an idea Ive had for a long time.

But I loved seeing it and spent a fair amount of time checking it out! Nicely done!!

 

[Rajobigguy]

That's considerably more than what is normally done unless it's a force induction application.

Barry:
I was only talking about piston to cylinder wall clearance.
I don’t do anything to the lower end different from any other performance build.

 

[obnoxious001]

Barry:
I was only talking about piston to cylinder wall clearance.
I don’t do anything to the lower end different from any other performance build.

Yep, I was just saying that's more piston to wall than I use unless it's a forced induction engine. Actually some of the newer design pistons with shorter skirts go as tight as .0005" over on an NA type deal. Racetec builds my pistons to the bore size and application I specify.

 

[Uncle Dave]

Has anyone ever done the Corvette n/a 7.0 Z06 engine in a boat? Small block with 500 hp/ 500 tq sounds like a win/win.
Even the C7 Corvette/Cadillac CTS-V LT4 supercharged 6.2 with 650/650 sounds like a winner also.

My 406 made 500/500.