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Manifold water?

B

Bill Taylor

New member
Greetings. Just. Did a valve job and replaced the exhaust manifolds on my 1988 454s. Yesterday ran both engines not under load. To day I loosened the manifolds to re torque the heads. Low and behold one manifold the left one on the port engine each exhaust port was quite wet. The question is where is the water coming from.
I did a pressure test and all are up to standard and no water was ejected from the spark hole.
After removing the manifold and inspecting the gasket there was no break and it looked as if the pressure was consistent at each port. The plugs were dark and not white. Give the cooling system of the engines the water must be coming from within the exhaust manifolds. They, the risers and elbows and all gaskets are new. Help please summer is fast approaching. Bill
 
Bad valve overlap can cause the wet exhaust to "suck" into the exhaust ports. Stock cam and the valve lash was correct?
 
The leak could have come from the gasket area if the bolt5s weren't retightened after a heat cycle, or the joint wasn't cleaned enough.

Jeff
 
When I read "gasket", I was thinking head to exh manifold, which, of course, doesn't seal water. Now, the elbow/riser square gaskets DO seal against water, and they require a re-torque after the first hot/cold engine cycle.
So, definately check all the new gasket bolts for 25ft-lbs or so.
 
Good. I know OSCO doesn't recommend it, but I use a LIGHT coating of silicone on both sides of the gasket where water could sneak by.

Jeff
 
Like Dave, I'm not sure just what you loosened to find water. I presume your object was to make clearance to remove the valve cover to get at the head bolts. If you loosened the riser/elbow connection to the exhaust manifold you may have failed to remove the small drain plugs in the riser and elbow first. If not drained, they will put a few ounces of water in the exhaust manifold. If you left the exhaust manifold and riser/elbow assembly intact and simply loosened the exhaust manifold/head connection to move the whole thing out of the way (kind of heavy for that...), and then you found water, then yes, you have a bum seal between the exhaust manifold and the riser/elbow as discussed above.
 
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