What are my options? 454 possibly cracked block

[WTR&PWR]

My buddy has had a 1998 commander 21’ jet boat that would be perfect for our days on Parker. Our mutual friend owned it and took it up to Idaho when he moved from havasu a couple years ago. When they decided to sell my buddy went up and grabbed it. Unfortunately it was around zero degrees out and they didn’t drain the water out of the block. They stored it indoors in temperature controlled environment but when he brought it home he drove through about 12 hours of freezing temps and found the freeze plugs popped out.

He has had it a couple years and lost interest in the project. He did some oil changes and ran for 30 seconds or so but keeps finding water in the oil. I always liked the boat and wouldn’t mind a lower river jet boat for the river house but trying not to dump too much money into it.

Numbers on the block are 10237297 which seems to show ‘96 and up bbc 454. Everything is still together and nothing has been torn apart. In the times he started and ran it made no unusual noises but the water in the oil is obviously an issue.

Questions- is there any reason to pull the heads and see if the crack is there or a head gasket? Or is it most likely the block?

Is there an on the shelf long block option that isnt full of Chinese parts that’s going to cause issues down the road?

Any options for a replacement is appreciated. I am not a motor guy. I’m in the trades and don’t necessarily want to take it on myself but that may change depending on options.

Price is right and boat is solid otherwise.

 

[DarkHorseRacing]

Depending on the vintage you could buy a world products block and just move everything over to it after the block has been washed and prepped by a shop.

We had our boat in freezing temps and the water in the block is usually 99% of the problem. Usually not a lot of other places that would give you water in the oil after it drains mostly out from sitting.

You could also have the existing block pressure tested first.

 

[3queens]

Tear down is in order unless you can see the crack ???

Good motor
Find the crack it’s vary possible to have it welded
If in cylinder wall it can be sleeved

 

[jetboatperformance]

Those blocks are pretty Hardy , cracked blocks are rare except for freezing or severe overheating , Is the engine stock (internals) , lots of options . Is the water in oil significant or slightly milky is the oil level increasing ? My engines are "no core" for Gen 5 and 6 BBC

 

[ChrisV]

New freeze plugs and send it

 

[WTR&PWR]

New freeze plugs and send it

He put new freeze plugs and ran it a few times and a few oil changes. Keeps finding water. Not a lot because he hasn’t ran it long.

 

[pixrthis]

It’s summer, I’d buy a short block from Summit and install it in a weekend. Time frame to have anything built right now puts you on the water at the end of summer.

 

[WTR&PWR]

Those blocks are pretty Hardy , cracked blocks are rare except for freezing or severe overheating , Is the engine stock (internals) , lots of options . Is the water in oil significant or slightly milky is the oil level increasing ? My engines are "no core" for Gen 5 and 6 BBC

He thinks it froze. It blew a freeze plug so could it have cracked and Blew a freeze plug? Trying to understand how it did both- or if it did both. What do you mean by your engines are no core? Does that mean you build a motor but don’t want core in return?

 

[WTR&PWR]

It’s summer, I’d buy a short block from Summit and install it in a weekend. Time frame to have anything built right now puts you on the water at the end of summer.

I have another boat option so time is not critical.

 

[jetboatperformance]

He thinks it froze. It blew a freeze plug so could it have cracked and Blew a freeze plug? Trying to understand how it did both- or if it did both. What do you mean by your engines are no core? Does that mean you build a motor but don’t want core in return?

Yes that's correct and if indeed your block is cracked internally It may not be repairable or desirable to repair , Gen 5 and 6 BBC blocks are all four bolt mains are fairly plentiful re the "freeze plug and a crack" yes both could happen simultaneously

 

[CSmith]

Is there potential it could be the headers and not the block? Not knowing anything about that exhaust, but if the water jackets cracked and it is backfeeding into the cylinders that way? Just a thought.

 

[DarkHorseRacing]

Is there potential it could be the headers and not the block? Not knowing anything about that exhaust, but if the water jackets cracked and it is backfeeding into the cylinders that way? Just a thought.

You’d be running the risk of hydro locking the cylinder if that was the case. That’s a quick way to a bent con-rod or worse.

Water in the oil is primarily from either damaged block water passages from freezing or you have too much water pressure in the cooling system and it’s overwhelming the gasket interfaces between the heads and intake manifold cooling passages.

 

[Dalton]

You’d be running the risk of hydro locking the cylinder if that was the case. That’s a quick way to a bent con-rod or worse.

Water in the oil is primarily from either damaged block water passages from freezing or you have too much water pressure in the cooling system and it’s overwhelming the gasket interfaces between the heads and intake manifold cooling passages.

I’ve seen the opposite……in my experience it’s usually reversion from the exhaust causing milky oil……i would for sure investigate the exhaust manifolds if I was OP

 

[CANUCK007]

Pull intake manifold .Have seen a couple crack lengthwise just above the lifter bores.Buy new and swap internals after measuring bores for piston clearance of course.

 

[HST4ME]

Pull the intake off, they crack under the thermostat housing. The blocks crack just above the lifters.

 

[Universal Elements]

That’s a 454 magnum

I have an extra one with the same numbers if you need to rebuild one. Barry (obnoxious001) would be good to contact for his opinion/recommendation.