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What is the Secret to valve cover leaks?

Norcalrv7

Well Known Member
What is the secret to keeping the valve from leaking? Silicone gaskets? Studs and locking nuts? Open to all input. Seem like my cork gaskets leak no matter what I do on my 360.

Caleb
 
What is the secret to keeping the valve from leaking? Silicone gaskets? Studs and locking nuts? Open to all input. Seem like my cork gaskets leak no matter what I do on my 360.

Caleb

The silicone gaskets are very good. Just don't over-torque the screws and distort the valve covers.
 
20-years ago, I removed the cork gaskets and installed silicone gaskets. 3,300+ flight hours later, still no leaks.
 
Yeah,,,,you can buy the "REAL" silicone gaskets for $$$, or settle for the "fake" ones that are non TSO'd for $. Both will leak if your stamped steel rocker box covers are distorted, bent up, and not flat. They will both leak if installed incorrectly also. :rolleyes:
 
Oh, I didn't mean you have to buy certified anything. It's just been so long since I've had to buy a valve cover gasket, the only ones on the market at the time were the REAL (brand) versions.

Charlie
 
The silicone gaskets are very good. Just don't over-torque the screws and distort the valve covers.

I have experienced no leaks with my covers and silicone gaskets. While replacing a cylinder recently, I looked up the Lycoming recommended torque and was surprised to see 35 in-lbs, which results in the gaskets squeezing out quite a bit. See Lycoming SL272A for details.

I backed it off to 25 in-lbs, which was more than I had previously but less "squishy." Time will tell.
 
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