351 gt40 water in oil

[Sydney]

hi does any body know if this is an option or not i need boat in a hurry,had heads serviced and pressure tested re installed water is still getting into oil have changed exhaust manifolds to Hitek stainless so have ruled them out.can i buy a 351 windsor long roller cam motor and transfer the computer and fuel injection and transmission or am i opening pandoras box

[DanielC]

Being in a hurry is not the best way to get good results. You may think you do not have enough time to do it right, but by taking shortcuts, you may be forced into doing it again.

Once water gets to the exhaust system, there is no oil system close by. I too think you can rule out the exhaust manifolds.

If I had this problem on my GT-40 engine, I would plug the water hoses coming off the thermostat cover, that go to the exhaust manifolds, and plug the water inlet to the engine, from the raw water pump. That should seal the engine. You can then fabricate some sort of an adapter, that has a fitting for a common automotive radiator cap on it. Maybe the adapter can incorporate plugging the water inlet, or the thermostat water outlets, but the point is to get the block sealed.
After you do that, a common automotive cooling system pressure tester will enable you to determine if the block indeed has internal leaks, or cracks.
Then you will know if you have to replace the block,

[Nautiquehunter]

Was it frozen? If it was you need a short block.

[AirTool]

Was it frozen? If it was you need a short block.

I'm with DC. I saw this post last night but was too tired to respond. What you haven't checked is the integrity of the water cavities. My suggestion was going to be the same as DC's but you don't need the radiator cap fitting. Cap off the hoses and find the highest NPT connection and build an adapter there. You could even thread in a Schrader valve or use a barbed hose fitting. Set your air compressor regulator at 5 psi or get a bicycle pump and have at it. This system operates with no pressure. If there is a crack, you'll be able to pump the water into the oil with little effort. Take the oil filler cap off and you'll be able to feel the air coming out the opening. If that is the case, you have a cracked block.

You can also watch the level in the oil pan using the dipstick.