Rocker Cover Oil Leak

Not a super cub but I know you guys are the sharpest tools in the bunch. So on my M6 with the O-540J Lycoming, I'm having a problem with one rocker cover leaking. The cork gasket began leaking on two covers, I replaced the gaskets on cylinders 2 and 4 with silicon gaskets, cylinder 2 is doing fine but cylinder 4 held for one flight and then started leaking again. In the last two months I've peened and sanded the original cover with fine grit on a flat pane of glass, swapped out the original rocker cover with a new rocker cover, tried a second silicon gasket, installed a cork gasket with sealer and still leaking, not much but enough to make a mess of the exhaust, firewall and belly of the plane over time. I don't know what I'm missing, I'm at the point where I'm considering using the following gasket maker as a last resort. Anyone care to chime in?
https://www.permatex.com/products/g...t-makers/permatex-optimum-black-gasket-maker/

Are you absolutely sure it's the cover or gasket leaking? With the efforts you have made, I would start looking for a very fine crack in the cyl itself or coming down from a push rod tube or ???? Your efforts should have fixed it and I find the fact that it didn't pretty suspect of something else.

Rip up an old Tshirt into little strips and tie one around the pushrod tube where it meets the cylinder and make a trip around the pattern. I wash the area with starting fluid to get it clean first.

Glenn

I'll use your method to check on the push rod tube Glenn, I'm hoping that's it and not a crack supercrow. Thanks guys.


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Check rocker drain fittings, too.

The Silicone gaskets don't like excessive torque.

50 in lbs. initially and then at least 40 after first flight and thereafter. Install dry.

All the silicone rocker covers gaskets I have installed say 20 in lbs. hot and 25 cold.

I have had the best luck just making them snug by hand. Plus, with the silicon gaskets it is important that the surface has no oil and is dry before install or it will leak by capillary action. Starting fluid is the best cleaner that I have used to remove an oil film.

Glenn

Steve Pierce said:

All the silicone rocker covers gaskets I have installed say 20 in lbs. hot and 25 cold.

Click to expand...

Opps: I was quoting from memory "Real Gaskets Service Letter" which had raised the value. I just called them and verified that they changed it back to 25 cold / 20 hot.

Discussed here. http://www.shortwingpipers.org/forum/showthread.php?8739-Real-Gaskets-Torque-Value-Change

Well Supercrow Thanks for snapping me out of my tunnel vision it is a pushrod tube seal leak not rocker cover. Thumbs up to strips and starting fluid Glen.


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