Found the reason for the water intrusion on my HP500
 

Someone replaced the intake with a new Dart piece.

Evidently, though, the heads have been milled to the point where the intake sits so high on the ports that the lower section of the water ports in the front of the intake have less than .060" of contact at the bottom edge.

Of course the gasket is gonna fail with no support there.

After a bunch of measuring, I am having .120" taken off of each side of the intake flange to get the ports to align better.

This was a close call, because luckily the water leak was very small. I never detected water in the oil during oil changes, and never saw any steam or anything coming from the breather hoses. There were some watery oil deposits on the underside of the valve covers, and some surface rust on the guideplates and the valley pan.

Other than that, the engine looks fine inside.

I guess there's no real point to this post except to make sure you check intake port alignment when installing a new intake....lol.... :angry-smiley-038:

Greg

I guess the person that built the engine maybe just took a grinder to the bolt holes instead of machining the flange surface, fitting it correctly the first time. I have seen that before. How did they get the bolts in?

Looks like someone drilled the bolt holes a few sizes bigger.

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Not the best solution...lol....

Greg

thanks for sharing

Ughhhh, some things you DONT take shortcuts with.

Very true.

Got the engine back together, ended up with .120" taken off of each flange, and .100" taken off the rails.

With a .060" thick gasket everything lined up just right. I found that the Mr. Gasket intake gaskets were the best match for the intake and heads. The Fel-Pro gaskets all had way too big of ports, both for the intake runners AND the water ports. Just an FYI.

Ran the engine on the hose and so far so good.

Man, this boat is SO close to being ready for the water...

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For your information, next time call Bob @ PERFORMANCE GASKETS CONCEPTS in Germantown WI Paper gaskets are a waste, I use nothing but, graphite with a stainless core. He may sell to you. Mark

Oh I see the problem the bolt holes are to small , Bob hand me that there drill with the big bit in it.