What needs to be changed on truck longblock to put in boat?

[craze1cars]

Currently have a 1999 Volvo 5.0L GL PWTR in my 20 ft Stingray. I put on a good 150 hours since buying the boat from a pawn shop with a disclosed freeze-cracked the engine block...but as strong as this motor is, I'm growing tired of my JB Weld patches repeatedly seeping, failing, and then having to redo the patches every few months....it's had a good run, but I'm declaring her done this winter, and I will be replacing the engine.

I have obtained a wrecked 1998 Chevy truck with a 5.7L recently remanufactured engine (factory Vortec specs/truck cam) that is as strong and solid as can be with fantastic compression...and this motor will be going in the boat. It will be run in freshwater only, raw water cooled.

I am fully aware that I will be changing EVERYTHING over from the original marinized 5.0L motor...carb, intake, risers/manifolds, distributor, alternator, starter, water pump, risers, etc etc etc...and I will have to get some manifold and intake gaskets and some other such things.

But what about the long block itself? Do I really need to knock the core plugs out and replace with brass, or is this unnecessary for a freshwater motor? What about anything else? I see absolutely no reason to pull valve covers, remove heads, remove cam, or anything of the sort....or am I overlooking something?

Thanks in advance for any experiences or thoughts on the project.

 

[RogersJetboat454]

Re: What needs to be changed on truck longblock to put in boat?

They are your dice to roll sir.

Chances are the truck cam will work OK, and the head gaskets and steel core plugs will be fine for a long time in fresh water, but again this is your choice you need to make.

P.S. If the block froze, I would be questioning the integrity of the manifolds, risers, and intake, and would THOROUGHLY check them before installing them on a "new" engine.

 

[craze1cars]

Re: What needs to be changed on truck longblock to put in boat?

Already been done...manifolds/risers were removed and inspected, and new gaskets installed back when I bought the boat. And as I said, 150 hours since I JB Welded the external block cracks, and she runs like a top with no oil/water mixing anywhere, and no water seeping back into the exhaust valves from the manifolds...so I'm not worried about 'em, but will certainly take a close look at them again during part transfer.

Intake? The intake manifold has nothing but air and fuel vapor, right? Which intake are you referring to?

I didn't consider head gaskets. Are marine head gaskets of a different material than auto head gaskets?

 

[Don S]

Re: What needs to be changed on truck longblock to put in boat?

Intake? The intake manifold has nothing but air and fuel vapor, right? Which intake are you referring to?

Think about it, what does your thermostat housing bolt to ...........

I didn't consider head gaskets. Are marine head gaskets of a different material than auto head gaskets

Yes they may be different.

Some gaskets have steal rings on them, marine would be stainless steel to prevent corrosion. IF the gaskets on the automotive engine are all composite, they would be ok. but you have no way of knowing without pulling the heads and looking.

 

[craze1cars]

Re: What needs to be changed on truck longblock to put in boat?

I personally know the guy who rebuilt this engine recently before it was wrecked. So I can ask him about the type of head gaskets he used and see if he knows. I have no objection to pulling the heads and regasketing them if needed...pretty easy to do while motor is out of the vehicle.

My t-stat oversight was a brain fart indeed LOL....but as it has been holding water just fine for several years after the freeze, I shall continue to use it, much like risers/exhaust manifolds.

So....if I am to understand this correctly, and I indeed want to do it right:

1. Brass core plugs
2. Verify head gaskets are NOT plain steel...change if needed. Composite or stainless are good.
3. Obviously 100% of the bolt-ons from the marine engine need to be transferred.

That's it? Please advise if there is more. Doesn't sound too awful difficult...

 

[RogersJetboat454]

Re: What needs to be changed on truck longblock to put in boat?

2. Verify head gaskets are NOT plain steel...

Not just an all steel gasket, but a steel cored gasket could be a potential issue too. Check with the dude who built it, and find out what gaskets he used. Doubt he will remember the part number, but then again there are some crazy people like that out there.

Sounds like you are on the right track with everything else. The core plugs are no big deal to change out. As a tip, I usually prefer to coat the rim of the core plug up with a little bit of gasket shellac to ensure a good seal;
http://www.permatex.com/products/au...matex_Indian_Head_Gasket_Shellac_Compound.htm

 

[craze1cars]

Re: What needs to be changed on truck longblock to put in boat?

Yes I do understand what you mean on the head gaskets...frankly I believe I probably WILL be getting the exact brand and part number. He's an engine rebuilder by trade...I'm thinking surely he has a particular gasket he'd normally order whenever he rebuilds a common 350 Vortec, and this one was only done a few months ago. So I suspect he will be able to tell me what his parts source is, and likely the part number he used.

I really do appreciate all the input, very helpful!

 

[bnicov]

Re: What needs to be changed on truck longblock to put in boat?

As long as the intake manifold isn't cracked and the risers are fine, you should be good to go with bolting it all up to the 350. Once it's back in the water, HANG ON!!! She's gonna be a heck of a lot quicker than the 5.0.