Leaking Rocker Covers - DON'T OVER-TIGHTEN

mshac · #1 08-17-22, 08:14 PM

I have the orange soft silicone gaskets - If you have cork gaskets, this does not apply to you.

My rocker covers were leaking oil, so I grabbed a big screw driver and tightened them firmly. I then started the engine to check if it was still leaking, and it had gotten worse!

I couldn't understand what was happening, so I did some research and found that the silicon gaskets have very specific torque values and install instructions.

Install the lower two screws first. The torque limit is 25 inch-lbs when first installing the gaskets, then re-torque to 20 in-lbs after running the engine to full power, or first flight. These are not high torque values!

25 inch-lbs is equivalent to only 2.08 foot-lbs. To get these values correct, you have to use a "Torque screwdriver" with an inch-lb scale.

When I over-tightened the screws, I actually deformed the valve covers! The area around the bolt holes gets bent down, so the cover isn't flat anymore. You have to hammer them back to flat which can be a challenge without the right equipment.

I ordered a new set of gaskets from Real Gaskets.com. They are $5.50 each plus s&h. https://realgaskets.com/product/valv...asket-4-holes/

Gasket installation instructions: https://realgaskets.com/wp-content/u...roved-2018.pdf

I've ordered this torque screwdriver to use upon installation: https://www.amazon.com/Screwdriver-M.../dp/B099N5VY7P

wslade2 · #2 08-17-22, 11:18 PM

Or the opposite: I was concerned about over tightening back in the winter. Replaced some old looking silicone valve cover gaskets. Put them on “snug” but not “tight-tight”. After some high speed taxi testing for brake work, a failed vacuum pump (for my OEM AI for my 400 autopilot) made me take the cowling off. Surprised to find a puddle of oil built up on the muffler, multiple liquid ounces. A fire begging to happen. Ran again after hand tightened more. Still leak. In short, problem wasn’t fixed until I used an inch pound torque wrench. Always use torque device with the silicone gasket or you might be surprised by oil loss or worse.

wslade2 · #3 08-18-22, 06:58 AM

PS-the leak didn’t show up at first with run ups. It only manifested itself with high speed taxi probably because that induces the full cacophony of vibration and pressures of takeoff.

mshac · #4 08-21-22, 07:01 PM

Quote:

Originally Posted by wslade2

PS-the leak didn’t show up at first with run ups. It only manifested itself with high speed taxi probably because that induces the full cacophony of vibration and pressures of takeoff.

That's scary. I'll definitely do a high speed taxi and re-check for leaks before going flying.