Wobble

You mentioned head bolts, verify that they have the correct and enough thread sealer. This is another way for water to reach the oil. Again, a pressure test will point you in the right direction.

As far as flappers go. A boat that had had no problems for 3 years hydraulic-ed after sitting on a beach for 8 hours, I guess the right combination of waves were able to push enough water up the exhaust.

I have s pipes and below the water line exhaust (at idle) I have the metal flappers built in (make a horrible noise at idle) but I would not be without them. If I did not have the slant cut tips, I would have gone with rubber. I think that good flappers may help a little with reversion also.

PatriYacht

I had the 651 cams in my 540's. With iron GM heads there was no reversion. Changed to AFR 335 cnc heads and had reversion big time. Had to go to dry pipes. There are a lot of things that cause water in the oil. Start with the simple ones. I doubt if it's the block.

SB

Yeh, the Gen VI 502 blocks have been flogged by harder hp and not had an issue. Supercharger's anyone ?

The 502 blocks have dry head bolt bosses - they do not go into the coolant like many other BBC's do. Wish all blocks where this way.

Maybe a dumb question - but why copper headgaskets in this application ? What is up with that ?

PatriYacht

Only head gaskets I would ever use in these applications are Felpro or Cometic. I use AFR's intake gaskets which are good quality and tough. Use hI tack gasket adhesive to hold it in place on the head and Permatex non hardening form a gasket on the intake side around around the water passages.

cstraub

Copper Head gaskets on an open cooling system. . .no way.

waterbum

I think the deck and head were machined to use o-ring. There was some discussion on gaskets last year. Like most topics, there are differing points of views. Here is one that stated using 0-rings and copper gaskets were common practice in some applications. Same thread also has supporters for cosmetic or felpro only. What's the "right" answer? Heck if I know!

http://www.offshoreonly.com/forums/s...ts#post1556279

In any case, good luck getting to a resolution.

Rebel_Heart

Thanks for the post on reversion - waterbum. It was mentioned that using this cam with my Dart Pro Ones may create a problem? How would this be different than using the iron heads? The gaskets have also been ear marked as potential problems. How do we find what is actually the problem? Or, do we just keep changing things until the problem goes away? This might be a long and expensive process!

Thanks again for your input. It is appreciated.

paradigm shift

Reversion? Maybe I missed it but what exhaust manifolds or headers?

Waterin both engines and wants to replace block? I would be betting on intake gaskets and a LOT cheaper. You can usually tell if it is pushing water by the gaskets. At least when I have had trouble you could see it.

Just my opinion and I am no expert. Oh my exhaust exit under swim platform and I run turndowns under the water. Never had reversion issues and on my third year. 2 years with blown 525 and this year with a warmed over 502mag mpi with CMI elbow tops. Hope you find it easy.

cig1988

Were the intakes checked w/a feeler gauge prior to installation ? Last year a buddie put two new intakes w/o doing this. Got to check to see if any gaps between the manifold and head. When I took the manifold off it was clear as day the "crush" was greater on the top by the water passages than the bottom.

SB

[QUOTE=Rebel_ do we just keep changing things until the problem goes away? This might be a long and expensive process!
[/QUOTE]

Guessing is crazy and if your engine builder wants to do this on your dime and/or time then it's your decision to stay with him or not.

Our guesses are guesses, but at the same time we are not there to check things methodoligically (sp?) so all we can do is convey are things we've seen.

So what do you do ? My advice, again, is to check the easy things one by one.

#1 Reversion will show it's face after idling for a while by leaving water traces in the exhaust manifold runners. Take them off after idling and look. Not much $$$ to do this.

#2 Intake manifold leakage is very common, as you can see by the responses. Remove intakes and check/measure for this. Even slight head and/or block deck machining can cause this to happen. + There are many different intake gasket thicknesses and patterns, so it could be as simple as this.

Here's a possibility/guess (since I wasn't there to see/measure/check) on the builders last water leak fixed by replacing the block deal. It's very possible installing new block only restored enough deck height that the intake manifolds sealed. Where, they could have noted how much deck material and/or head surface they removed and milled intake manifold to proper dimensions to restore proper clearance. And/or used different thickness intake gasket. Above, just thrown against the wall.