I have twin '79 440s in my boat. I am fighting the symptoms of blow-by on one of my engines (weeping valve cover gaskets, oil drool around PCV and air breather on opposing valve cover). Air breather has a hose to flame arrestor already.

What if I took the PCV out of the equation and ran a straight elbow out of the valve cover to my AFB to ease up on the crankcase pressure? I run my engines only at 18-1900 rpm. Should they be ran harder to ease up on the vaccuum? I am grabbing at straws on this. Top end was done about 100 hours ago. Engines run well with good oil psi. It's the weeping gaskets that has me concerned.

Thanks

 

I'm reluctant to give advice in a marine situation because of the obvious bilge explosion hazard.

The fact that one engine exhibits this indicates a problem with that engine. Weeping gaskets are a sure sign of excess crankcase pressure.

First something simple like a restricted / plugged breather/ PCV / hoses

Second, blowby in that engine, caused usually by either valve guides, rings, or a more serious cylinder/ engine problem. Broken ring, cracked piston, etc.

How is oil pressure between the two engines? Is the problem engine running excess oil pressure?

Compression test/ leakdown test might help.

 

Boat is special situation, But It needs to have the PVC I would make sure you have good VC gaskets. Not the cheap cork type And that the covers are straight, it should have some triangle shaped washers/ long bars maybe ?? for the VC bolts too.. You should run it harder once in a while or the rings could carbon up

 

Thanks for the responses. I have used good gaskets (Fel-Pro) and fabricated long bars to spread out the bolt's hold. The oil psi is good. The problem engine at idle is 40 and underway (1900rpm) is at 60. The other engine is a little lower, but both have good psi.

 

I should also add, comp test last year showed 7 cylinders at 145 and one at 125.