Buy headers stop fuckIng around

Ok then buy heads and headers

They're separated by a blockoff plate with two gaskets each side. Water goes through manifold for pre heat, then through block and out into the exhaust through the risers.

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How sure are you that this is where the water is coming from in the first place?

If your going to weld those ports up you will have to mill them anyways.....

Your doing something wrong......Is there a small hole or holes (like 1/8") somewhere in the block off plate? there should be.

How certain are you that there is not a crack somewhere?

This is almost silly.   If both surfaces are flat and you have new gaskets, the only way this could leak is if they are broken or you are using silicone sealant on the gaskets and over torquing the hell out of the mounting bolts.

The only issue I see with welding them closed is that it wont solve your problem and would be a waste of time/money....

GT

Had the jacket ports welded up and surfaced. Water isn't configured to run into risers from manifolds otherwise water that's supposed to exit would be trying to re-circulate back into cooling system, and a certain amount of cool water entering the manifolds would be bypassing the block and heading out through the riser and gone with exhaust.

Water is plumbed in from jet to pre heat in the manifolds, from there water exits the front of manifolds and goes into front of block. Water that exits top of block is hosed into the front of each riser and out with exhaust down the tubes and keeping flappers happy.

I'm sure that's where the water comes from, its always leaked on the outside so I always imagine its leaking inside. The two cyl's below riser that was leaking when I bought it have lower compression than the rest.. maybe crusty valves or rings due to moisture. As tip top as it is running now, not gonna pull it apart anytime soon, just wanna keep the water out.
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first off... what psi is getting to the exhaust? is there a pressure reguator or are you trying to hold 50+psi at your manifold/risers with a gasket?

Is that plumbed from factory that way? I mean, the water outlets going to the snails, is there a boss there that looks like it was suposed to have a hose fitting there?

They're not Berkeley, BTW, BUT could be a cousin!

Ray

 http://i270.photobucket.com/albums/jj114/ro69rag/motor.jpg

Here's a better pic of how the leaky risers look on someone else's boat.

Lookin like Marine Power plumbed all their big blocks that a way. 

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Nah, worst case is header time, but is rather have those built when the motor is on a stand... I'd really like to get another big block and start building one little by little in its own corner of the garage.

But anyways, I'll see how this works.. might ought to fix the symptom of too much pressure, I know that the gate valve had to help with pressure and obviously operating temp.

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