[August 24, 2015]

Last week when I posted my writeup on the VansAirForce forums, someone pointed out that it seemed like I had a chunk missing out of the side of the exhaust port on the bottom of the cylinder. Under closer inspection, I was missing a chunk!?! I was a little worried, so I called up Superior and sent them the picture. They didn't seem too worried, but it took us a while to come up with the proper solution. I couldn't continue to use a traditional spiral-wound gasket wasn't large enough in diameter to prevent any gasses from sneaking by.

Here is the spiral-wound layers. You can see how there is discoloration where the exhaust is leaking.

The solution Superior and I came up with was to switch to use traditional copper gaskets. They are installed in pairs (per Lycoming Service Instruction 1204D), with the bead side towards the exhaust.

A blow-up of the important installation instructions of 1204D.

I decided to put some Ultra Copper High Temperature RTV on the cylinder side of the copper gasket, hopefully to slightly fill the chip in the exhaust port.

I use some thin safety wire to keep the gasket in place while I mount up the exhaust.

I noticed when I took my cowling off there was some oil drips on it right underneath of all of the valve covers. Investigating this further, it looks like almost all of my gaskets developed cracks! I didn't think I cranked down on the screws that much.

Oil burning off under the #2 cylinder.

A badly cracked gasket on #1

This is off the #2 cylinder.

Notice the big chunk that fell off into the topside! I have 4 new gaskets coming from Van's - in the mean time I'll try to figure out the proper torque to use.



Last Modified: August 13, 2023