National Aeronca Association Bulletin Board

I'd be more tolerant of leaking valve cover gaskets if my Champ had been made by Norton, Triumph or BSA, or Harley Davidson.

I have new Millenium cylinders and paid for the silicone "no-leak" gaskets so I expect no leaking, but they still ooze like pus from an injured dog.

Last year, I pulled the valve covers, checked them for flatness, cleaned the mating surfaces with contact cleaner and used Gask-a-cinch, a thin rubber cement-like sealant, and they still leak! WTF!

Anybody have a solution, short of welding the covers on?

Thanks,
Jim

I keep an oil drip pan under mine Champ

It does seem that with the '"improved" silicone gaskets the screws tend to loosen up after some running. I have the same problem on my 0200. I solved it on my A65 by safety wiring all the screws once I had them tightened down. I actually lost a couple of screws that I know were torqued. I'm going to try wiring the screws on my 0200 but need to buy screws with holes first. The only other thought would be high crankcase pressure that would tend to push oil out.

MikeB

Make sure to check the manufacturer's torque spec and follow it closely. Over torqueing is more likely to cause leaks than under torqueing.

Brian Walker
'46 7 AC/DC

Also, I learned that the gasket and the surface has to be completely dry of oil in order for the gasket to grab and work. It goes a little against the grain, since you
are looking at a oily mess probably, but it makes sense. Take the gaskets off, clean the surfaces and the gaskets so they are completely free of oil. Install to correct
torque and no more and it will work.

jimboe wrote:I'd be more tolerant of leaking valve cover gaskets if my Champ had been made by Norton, Triumph or BSA, or Harley Davidson.......

Thanks,
Jim

I have never had a harley that leaked from the valve cover, save one "tin top" and th' knot-head that installed them didn't properly install them (left the D rings off).

I've used the silicone gaskets with great success, The silicone gaskets are softer than the old cork ones. and vibration will allow properly torqued (torque based on the use of cork) screws to work loose. A dab of loctite on the threads, and proper torque will work wonders.
One thing that the silicone gaskets need is a metal insert in the screw holes, which will allow the proper torque to be all that's needed.

Thanks for the replies and ideas, guys.

I have come to the conclusion that it doesn't leak so bad that I need a oil pan. It just drips a little on the inside of the cowling and I can wipe it off.

I did learn one thing - Do NOT use Gask-a-cinch to seal the gaskets. The head temps will burn it and make it hard to scrape off.

Clean, dry surfaces and silicone gaskets with correctly torqued screws are as good as it gets.

It's just not worth being irritated about - not like $6.35 av-gas.

Jim

Check to see if the leak is from the pushrod tube where it enters the head.

Jerry Jackson
7ECA 65TC
8T8

I personally don't care for the soft gaskets. I use the cork, clean the surface,on both sides. I use halomar and I coat the gasket, place it on the valve cover, set it over nite, place halomar on the gasket and place the valve cover on the engine. use the torque table, and tighten like you would tighten a cylinder, down. You can safety wire if you like, I usually check after I fly the aircraft, I think the halomar secures the screws, I very seldom find a loose screw, I also use this process on the stud and aluminum valve covers. It works, any aviation supply usually carries halomar, Its Blue in color, your cork will never stick and very easy to remove and clean with MEK and scotchbrite. Also if she is leaking you know your getting good lubritation in the valve covers. I know an aviator that loves to see it leak he then knows it's lubin. A fellow aviator Sunny

I installed new silicone gaskets from realgaskets.com along with brand new screws on my C90 and she runs perfectly dry. The torque is important as over-torquing will make them leak.

Dan