I just put 4 of those on mine. They are very nice and I have to imagine that they will hold better than the cork. Of course I only have about 5 hours on the new ones, so time will tell. Thus far they have not leaked.
 
gaskets

Vince,
The rubber ones are best.
My opinion is the cork is a one shot gasket but the rubber is re-useable.
you won't be sorry.
Bob Martin
 
I have used theses gaskets on several engines for many hundreds of hours and have only had to replace one gasket because it got a cut on it.
Cork gaskets burn on to the valve covers over time and you usually have to scrape them off, if you haven't had them off for a while. The rubber ones come right off and can be used over and over with no problems.
I recommend them.
 
rubber valve cover gaskets

I changed mine about 50 hours back not because they were leaking but because the bolts kept coming loose on the valve covers as the cork gaskets compress and bake. I haven't had another loose bolt since changing the gaskets.

Blues Skies,
Bryan
 
Rubber valve cover gaskets

I put 4 of them on before first flight, and they have not leaked at all in 2200+ hours. I run the screwdriver around them at every oil change :) Rosie
 
Can someone tell me how much to tighten the valve cover screws. I just replaced two of the cork gaskets on my IO-360 with the rubber gaskets and tightend the screws as tight as I could get them. Today an A&P guy saw my gaskets and said they were too tight because of the way the rubber appeared to bulge out around the edges and that this would cause them to leak. However, the gasket is thick enough that I think it will bulge regardless. Anyone able to help me out?

Thanks,
Tobin
 
Rubber valve cover gaskets

Tobin,

If I remember correctly the toque should be 25 in-lbs. The mechanic is correct, if you overtighten them they will leak.

Brett
 
I like the corks better myself. The silicone ones can be overtightened by a careless mechanic and start a significant leak. Of course, since you guys do your own maintance, that isn't as much of an issue, but the cork ones are much more idiot proof.
 
I just replaced my cork gaskets:

http://photos1.blogger.com/blogger/1342/535/1600/P5041450.jpg

The silicone gaskets I replaced them with should avoid the problem you'll see in that photo. Apparently prior owners just kept tightening the valve covers if they saw any seeping oil, finally getting the cork to the point where it was simply pushed out or crushed to nothing, and firmly stuck to the engine head. Yuck.
 
Too much of a good thing

tobinbasford said:
Can someone tell me how much to tighten the valve cover screws. I just replaced two of the cork gaskets on my IO-360 with the rubber gaskets and tightend the screws as tight as I could get them. Today an A&P guy saw my gaskets and said they were too tight because of the way the rubber appeared to bulge out around the edges and that this would cause them to leak. ....Tobin
Click to expand...
Tobin,

A seasoned mechanic told me this is a common and classic location where over-torquing greatly increases the chances for leaks. I found out on my O-200 when I became too ambitious on those valve cover screws after an engine MOH. I was at a loss as to why a cover continued to leak after installing brand new silicone gaskets. I learned the hard way over-torquing can distort the screw holes on the valve cover. You can in effect generate (an exaggerated) sort of dimple around the screw hole itself. If that happens, no amount of torque will stop the leaks. Examine the valve cover carefully and determine if it is in any way distorted around the screw holes. If so, carefully hammer back into shape and try again.
 
tobinbasford said:
Can someone tell me how much to tighten the valve cover screws. I just replaced two of the cork gaskets on my IO-360 with the rubber gaskets and tightend the screws as tight as I could get them. Today an A&P guy saw my gaskets and said they were too tight because of the way the rubber appeared to bulge out around the edges and that this would cause them to leak. However, the gasket is thick enough that I think it will bulge regardless. Anyone able to help me out?

Thanks,
Tobin
Click to expand...
It so happens that I have the Lycoming Direct Drive Engine Overhaul manual right in front of me.

Page 1-34, ref new 905 (ref old 835) 1/4-20 Rocker Box Screws

50 in. lbs
 
Torque- Cork or Rubber?

Bill,

Is the torque value for cork or rubber...or does it matter?

Thanks,

Sam
 
7A_@ABI said:
Bill,

Is the torque value for cork or rubber...or does it matter?

Thanks,

Sam
Click to expand...
Sam,

Good question, I have no idea as the book I have only lists the part as "Part number 61247, GASKET, Rocker box" and doesn't list what it is made of.

For those of you who have never seen one of these books, it is right out of the 40's. The first and thicker section deals with all direct drive Lycoming engines. This includes the 235, 290, 320, 360, 540, and 720, etc. and every version of each, L, T, V, H, A, I, G, S, O and all the suffixes of each. There is a second manual that lists the parts for my O-290. The torque values are found in the back of the main OH manual and apply to all Lycoming engines, unless otherwise called out.

I would check with someone who knows engines better than I to answer your question. I only know what I read in the book and the book doesn't list the gasket material. Mahlon and a local IA recommended cork for my O-290-D2, thus that is what is getting installed.
 
Not sure what brand of gaskets that Van's sells, but I put "Real Gaskets" brand on my Franklin poweered Stinson 10 years ago-------they stopped ALL leaks from the valve covers, and pushrod tubes.

The torque factor was extreemly small, something like 50 in/oz, took a special tool called a "torque watch" (if my memory is correct) to even get that low.

Real Gaskets are on the web, well worth the price.

As someone else already mentioned, check the covers for flatness around the bolt holes.

Mike
 
Mike S said:
Not sure what brand of gaskets that Van's sells, but I put "Real Gaskets" brand on my Franklin poweered Stinson 10 years ago-------they stopped ALL leaks from the valve covers, and pushrod tubes.

The torque factor was extreemly small, something like 50 in/oz, took a special tool called a "torque watch" (if my memory is correct) to even get that low.

Real Gaskets are on the web, well worth the price.

As someone else already mentioned, check the covers for flatness around the bolt holes.

Mike
Click to expand...


How are the pushrod tube gaskets serviced; by removing the valve covers? At first glance it looks like the whole cylinder needs to be removed, or at least loosened. Surely not.... :confused:
 
To service the pushrod tube seals, remove the valve cover and remove the shroud tube spring. The tubes will slide out through the head after the rocker arms and pushrods have been removed. There are other considerations such as keeping the parts identified for correct reassembly. If you need to ask this question, you should probably get the help of an A&P.
 
Thanks for all the input from everybody. I found this quote off of a Q&A website for "Real" gaskets:

Q) My mechanic warns against over-torquing the stock cork valve cover gaskets. Can I ruin them by over-tightening them?
A) Not under normal circumstances. Actually, they don't require much torque (20-25 inch pounds), but unlike cork and neoprene that can be ruined and permanently deformed by over-torquing, AMS silicone gaskets are far more forgiving. However, with this said, extreme over-torquing can harm most any gasket including REAL silicone gaskets even though they are more forgiving than other gasket compounds. It is vital you (or your shop) follow the instructions included in each package because as a rule, they DO NOT require as much pressure to seal as other gaskets.

Here's the whole page: http://www.magnalabs.com/realfasketfaq.htm
 
Silicone Gaskets

I think you will find they are a problem too. I've always had good luck with new cork gaskets every couple of years. Permatex #2 on the engine side, or both sides with a leaker.

John
 
I use the silicone (rubber) gaskets and have been very pleased for 800+ hrs. Use split lock washers to help "live load" the screws holding the valve cover in place. Might help it stay tight.
 
Sealant

?? Hey engine guru's. Do you use any kind of sealant on the silicon gaskets? Prep them in anyway?
 
Silicone and Sealant

JonJay said:
?? Hey engine guru's. Do you use any kind of sealant on the silicon gaskets? Prep them in anyway?
Click to expand...

Do not use any sealant on the silicone gaskets. You do need to assure that the cyl surface is clean of any oil. Use MEK, isopropyl, lacquer thinner, etc. This sounds crazy, but wash the gaskets with dish soap i.e. Dawn, to get any oils off before installation.
The previous posts about torque are correct. The torque value is ridiculously low, but if you exceed it, they will leak. (see a previous post by Mike)
The silicone gaskets are great, and if properly installed will far out perform the cork gaskets
 
"Real" Gaskets v.s. OEM (silicon)

By chance I had both. The "Real" Gaskets are twice as thick and significantly wider than the OEM gaskets. This presented a problem for me as the edge of the baffling interferes with the wider "Real" Gaskets prohibiting me from using them without trimming the gaskets (did not like that idea) or modifying the baffle (liked that even less). So, the OEM silicons went on, which are exactly the same size as the cork.
My engine was new and the cork gaskets started leaking a little almost immediatley. After 250 hours, it was time to change. Don't let them go that long! Although not a big deal to clean up, the simple job of changing the gaskets took much longer as the cork had cooked itself to the cylinder and valve cover.
I would recommend that you change to Silicon even before your first start. Perhaps the newer baffle kits have more clearance than those that came with my 6 but if you are going to use the better "Real" gaskets, make sure you put them on before you start your baffle so you can deal with the interference issue if there is one.
 
I think everyone should realize there are two kinds of cork gaskets. One of them is the kind that leak. The other one is the kind that doesn't leak yet, but will pretty soon. The silicone gaskets don't leak if installed correctly. Don't use any 'sealant' on them, just clean the surfaces, and don't torque them too tight. Just tighten the valve cover evenly until the gasket starts to bulge out just a little. They shouldn't leak after this until overhaul. If they do, you probably didn't put them on quite right. Take it back off, reclean, and re-install.

Scott
RV-8 FB
 
One small thing to add to what Scott said, before you reinstall the cover, be sure it is flat on the mating surface.

You will be surprised at how much distortion there can be around the screw holes.

A little work with a small hammer will work wonders.
 
Silicon...

gaskets only on my planes, star washer included on the screw and tighten till the screw seats the cover and a little over 1/4 turn more. No leaks and reusable again and again. :)
 
The kit comes with torque value........... Just follow the installation instructions. I torque the valve covers and the exhaust at each condition insp. The torque is writen on the baffle.
 
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