valve cover leaks

tomnj

tomnj

Old fogie stogie
I adjusted the valves on my 903cc the other day and put a fresh new gasket on the valve cover. About a week later I noticed the valve cover is leaking. I re-tightened it (not too tight, just made sure it was torqued evenly). Same leak. I am about to tear it down again and put on another gasket. It seems to leak on the exhaust side.

So the question is... what is the best way to prevent leaks? I used a new rubberized gasket I had laying around as part of a gasket set from years ago. Are the cork ones better? Is gasket sealer a must? Coincidentally (or not), I added the missing crank case hose to go to the air cleaner assembly. It's possible that restricted crank case gasses somewhat (though I doubt it, the hose is large enough and no kink) that could have been related to the leak. However when I removed the hose, the leak didn't improve.
 
RocketMonkey101 said:
I haven't' adjusted the valves on my 850 yet but I use cork on my VW and it always seems to work for me.
Click to expand...

I use cork on my Super Vee. I RTV the gasket to the valve cover and leave the head side of the gasket dry so I can remove it to adjust the valves. It's harder to get the gasket off when you need to change it but it lasts for a year plus and doesn't leak.
This works better if the valve cover has a channel, but it still works without it if you let the RTV cure a little longer before you reinstall the valve cover.
 
When I remove and reinstall the valve cover in my 850 based Lombardi, I make absolutely sure that both surfaces are clean and dry using brake-clean on a shop towel. It's a rubber gasket and is torqued down nice and snug but not overdone. I haven't seen a leak yet. You may want to check the cover for warp. I have been told that this is common at the exhaust side back corner.
 
Rocker cover leaks aren't uncommon and I think cork is a better choice. Instead of RTV, you could also use "high tack" gasket sealant like Permatex or Loctite.
 
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