Easy way to check headers for water leaks?

[TIGGER]

I recently bought a Marlin Jet boat with a Olds power plant. The motor has Nicson log type headers. My motor has a water leak somewhere that mixes into the oil. A guy I work with was telling me today that he owned a boat a couple years back that was doing the same thing. After countless hours of replacing head gaskets, it turned out to be the log manifolds were leaking.
I am wondering if that could be my problem since the motor was rebuilt not too long ago. Is there an easy way to check the manifolds?
What is the easiest way to get them off? If I take them off, what type of gasket do I need between the header and engine?
Any help would be appreciated.....

[1978 Rogers]

Sure it's easy to check for leaks. Un hook the hoses from the manifolds. YOu might have to take the logs off the block for easier access. Buy some threaded plugs and couple of nipples, threaded "T", pressure gauge & an air inlet. Plug the holes. Put togeter the T, nipples, pressure gauge and inlet. Stick this in the other treaded fitting. Pump up the manifold to about 30-40 PSI. You can use a tire pump since this is a small valume of air. Check you fittings for air leaks with soapy water. You don't want any. Come back and check the pressure after an hour. If it drops you have a leek in the logs.
Someone might have an easier way, but this seems pretty simple to me.
We do this on all our comercial irrigation systems we install. We have to pump them up to 105 psi. The pressure can only drop 5 psi over a 2 hour period.

[460rogers]

How could a leaking log let water into engine oil? :confused:
My bet would be timing cover leak.

[TIGGER]

The guy I work with said on his exhaust logs there were some plates inside that were pitted / rusted. He suspects the motor was pulling water in thru the exhaust valves. All I know is that he replaces the plates inside and his water problem was gone?

[GlastronGuy]

How could a leaking log let water into engine oil? :confused:
My bet would be timing cover leak.
That or intake manifold.

[dave186]

here is what happened on my boat. it had been sitting for a few years and the owner had drained the water out of the block but didnt touch the manifolds. so they had water sitting in the bottom of them and one of them cracked on the inside. the way its plumbed the water goes through the logs then into the engine. well with one side cracked no water ever made it into that half of the engine. this wasnt apparend because the temp gauge is in the top of the manifold and the one side was getting plenty of water. i guess the one side of the engine overheating caused water to get by a gasket and would mix in the oil. i went so far as to pull the heads and replace all the gaskets before i figured this out.

[Cas]

yep, intake manifold or the water pump cover is my bet.

[TIGGER]

I got the exhaust logs off today. Can someone explain how they work? There are three hose connections. One under the manifold that connects to the thermostat housing. Two up front, one goes to the timing cover the other goes to a T that is under the motor. THe T under the motor looks like it goes to the pump via a hose valve?
I have read a couple other posts about too water pressure and installing a gauge. Could someone please explain that a little more and possibly post some pictures?
Thanks