Pirep for real silicon gaskets.

[Will.iam]

Just replaced my leaking cork gaskets with real silicone gaskets and after the test flight i was pleased with no leaks from any of them and surprised at how much of the belly oil was from the gaskets leaking and not from the oil breather tube. Much less clean up after the flight. The left side cylinders 2,4 and 6 were very hard to get the cork gaskets off compared to the right side that just came off in a single piece. I don’t know if that was due to higher heat issues or if the right side has been replaced before so maybe not on there as long. But an xacto hobbie knife and the thinnest wood chisel really help to get the old gasket parts off. Also both surfaces have to be completely dry or the silicone gasket will squish out from the compression. After torquing to 25 in-lbs and a runup, you go back through and check each screw at 20 in-lbs after that i put some yellow torque checker paste so i can identify when any of the bolts start to loosen up. 

[ilovecornfields]

Don’t freak out if you get increased silicone in your next oil analysis.

[A64Pilot]

If you have access to a grinder with a wire wheel as opposed to a stone they are outstanding for removing cork gaskets.

For many years the standard was to adhere the cork to the valve covers with contact cement, this held the gasket in place for assembly but without the wire brush made clean up a real bear, a thin layer of grease kept them from bonding to the head.

Even if perfectly installed cork gets brittle and shrinks, hardens with age and will leak. Cork has to be replaced every so often

[kortopates]

Now i see why your only doing 110 kts LOP. You’re flying inverted! That’s no way to enjoy the scenery

The gaskets also have to oil free the next time they get re-installed or they will leak.
Also after some flight hours, be sure to check torque is still good at 20 inch-lbs. these last almost forever if not over torqued.


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[Guest]

7 hours ago, A64Pilot said:

If you have access to a grinder with a wire wheel as opposed to a stone they are outstanding for removing cork gaskets.

For many years the standard was to adhere the cork to the valve covers with contact cement, this held the gasket in place for assembly but without the wire brush made clean up a real bear, a thin layer of grease kept them from bonding to the head.

Even if perfectly installed cork gets brittle and shrinks, hardens with age and will leak. Cork has to be replaced every so often

Only applicable to Lycoming engines, I’ve never seen a cork gasket in a Continental engine.

[A64Pilot]

1 hour ago, M20Doc said:

Only applicable to Lycoming engines, I’ve never seen a cork gasket in a Continental engine.

Only applicable to cork gaskets  

As the thread starter included pics of a Conti and spoke to changing the cork gaskets on it, I’d suppose at least one had cork?

But irrelevant I spoke of gaskets, not engines.

[Guest]

It has cork gaskets along with being installed upside down,  some skilled maintainers out there.

[Will.iam]

It was definitely cork i can attest to that. 
 

[A64Pilot]

Honestly, it looks like paper to me, but I’m looking at it on an Ipad.

‘I have never seen colored cork, all I’ve seen is it in its natural color, all I’ve ever seen looks like this

 

[Will.iam]

25 minutes ago, A64Pilot said:

Honestly, it looks like paper to me, but I’m looking at it on an Ipad.

‘I have never seen colored cork, all I’ve seen is it in its natural color, all I’ve ever seen looks like this

 

I’m no expert maybe it was colored paper but i do know it wasn’t silicone as it was hard and cane off in chunks. 

[EricJ]

2 hours ago, Will.iam said:

It was definitely cork i can attest to that. 
 

That's not cork.   That looks like silicone or RTV.

[Fly Boomer]

7 minutes ago, EricJ said:

That's not cork.   That looks like silicone or RTV.

I'm going with old, dead silicone.

[Guest]

Hate to burst bubbles, but is just plain old Continental paper gasket material.  A sharp razor blade or small sharp wood chisel for removal.

[kortopates]

2 hours ago, Will.iam said:

I’m no expert maybe it was colored paper but i do know it wasn’t silicone as it was hard and cane off in chunks. 

They're not cork but stamped paper gasket. Those look like the most popular Superior version I detest since the paper bonds to the aluminum after years of heat making them difficult to get off and clean up. IMO the silicone ones pay for themselves in the amount of time they save; besides being re-usable. 

The only silicone version is the Real Gaskets.

[Will.iam]

Amen brother they were a pain in the ass to get off on the left side. The right side was easy in comparison and thank god or i would still be over at the hanger working on removing them if they were as bad as the left. Both sides were leaking so the degree of baked on does not correlate to the amount of leaking that was going on. Strange thing is they just started to really get bad in the last 6 months or so or at least that is when i started noticing alot more cleanup on the belly.