Rocker Box gaskets

[triple8s]

In the annual process and my rocker boxes are seeping, the mechanic said we need to replace gaskets so I ordered some new ones. Well, the day after I ordered them my friend had replaced his rocker box gaskets and he got his from a place in California that sells them with a reinforcing ply and theyre also a bit thinner. What's the consensus about which kind of gaskets, I have some of the non-rienforced gaskets and I have seen those get oil soaked and stick out causing a leak Oh I have the little 5-hole gaskets (TCM 550-G) and I am not sure if these are problematic but I do know of an instance where a rocket had rockerbox leaks bad enough to lose oil and while at altittude, the pilot had to make an unscheduled landing and have things fixed. I dont want to be in that situation. The reinforced gaskets come from GEE-BEE here is a link if anybody wants to take a look see.

 

                                   http://www.csobeech.com/GeeBee.html

 

 

[OR75]

i get the cheap ones made of cork material and always have a few in stock 

each time I open the cowling, I check that the bolts are snug but not too tight

once in a while I change the gasket

[Guest]

If you're using TCM paper gaskets be sure to use TiteSeal from Spruce. If you're using silicone gaskets be sure both surfaces are absolutely clean and dry before installing. In either case you should make sure use check the metal cover for flatness by lightly running them over a piece of sand paper stretched on a flat surface.

Clarence

[Mooneymite]

Two choices:  Gaskets that will eventually leak, or silicone.  

[kerry]

I like cork. I lightly apply 100% silicone that's smeared as little as possible to both sides of the cork.  They never leak and when I do take a gasket off it's easy to clean.

[jetdriven]

I have used silicone gaskets and cork coated with Permatex Aviation sealer. The ones made by Gee-Bee appear to be an improvement over the thick silicone ones. Those tend to deform the stamped Lycoming valve covers because the silicone gaskets creep out from under the cover and "run away" from the clamping torque.  You can see this, the silicone gasket extrudes from under the cover near the screw heads.

[wishboneash]

I have the exact same issue (cyl #1) in my IO-360 engine. The cover may be distorted. It seems there is no reinforced silicone gaskets available for this engine. Thanks for the tip on the Permatex aviation sealer, Byron.

[Piloto]

Forget about the cork gaskets. They leak the moment you tighten the cover screws. I have been using the orange silicon gaskets for over twenty years and never had a leak. Unlike the cork or paper gaskets that need to be scraped any time you remove the valve cover the silicone gaskets can be reused again.

 

José

[1964-M20E]

Forget about the cork gaskets. They leak the moment you tighten the cover screws. I have been using the orange silicon gaskets for over twenty years and never had a leak. Unlike the cork or paper gaskets that need to be scraped any time you remove the valve cover the silicone gaskets can be reused again.

 

José

+1

[StevenL757]

Triple8s - use these below...seriously.

 

http://www.realgaskets.com/files/horizontal.htm

 

Part number = RG-632459 (IO-550G, N, et al series)

 

$4.75 each or a package of 12 for ~ $57 + shipping.

 

I'm on my second set in as many engines.  Just had my IO-550N8B installed a few weeks ago, and the first thing I did was pull off the factory TCM gaskets and install these (see picture).  Forget cork - these are clearly the best.  I have yet to find anything over 1 drop of oil collectively underneath all 12 rocker box covers.  Also, when I removed some of the covers on my retired IO-550G6 after 1036 hours, they came right off - no peeling or scraping anything to get them off cleanly.

 

I re-torque them to 40in/lbs every oil change (normally done every annual, but I ensure they're always up to spec several times a year).  NEVER had an issue with them.  Let me know what you decided (or decided).

 

Steve

[triple8s]

Well, I had scraped the TCM gaskets off of #5,3,1 cylinders and had already ordered and received the "Real Gasket" gaskets, I had called Guy @ Gee Bee and he said he hadn't made the 5 hole TCM rocker cover gaskets yet but was going to set up to do just that, said it would take a few weeks and he'd call. I went ahead and had the Real Gaskets put on the 3 I had cleaned because I want to fly like NOW! I thought I would see how these do, the left side of the engine is just like the right side was a wee bit of seeping so I checked the screws to make sure none were lose and thought I'd fly it and keep an eye on them. If they don't give any trouble I will probably have the rest put on at next oil change and put the Gee Bees on the shelf when they show.

[StevenL757]

Well, I had scraped the TCM gaskets off of #5,3,1 cylinders and had already ordered and received the "Real Gasket" gaskets, I had called Guy @ Gee Bee and he said he hadn't made the 5 hole TCM rocker cover gaskets yet but was going to set up to do just that, said it would take a few weeks and he'd call. I went ahead and had the Real Gaskets put on the 3 I had cleaned because I want to fly like NOW! I thought I would see how these do, the left side of the engine is just like the right side was a wee bit of seeping so I checked the screws to make sure none were lose and thought I'd fly it and keep an eye on them. If they don't give any trouble I will probably have the rest put on at next oil change and put the Gee Bees on the shelf when they show.

 

Nice.  The blue baffling material on my engine came from him, and as those were pre-cut, I had very little trimming and modification to do to make them fit.  I'm happy with Guy's work so far, and would buy baffling material again from him when the need arises.

 

Excellent that you went with RealGaskets.  You've obviously noticed the thickness and overall fit & finish.  Get those remaining gaskets changed out, follow the instructions (torque to 50 in/lbs initially, then to 40 after an initial flight following installation), and I know you'll be happy.  Let us know how you make out, and post a pic or two of the completed job when able.

[FlyingDude]

Guys,

One of my rocker cover gaskets is leaking and this is the FAA approved PN:

https://www.aircraftspruce.com/catalog/eppages/siliconecalvecover_08-01316.php

BUT...  It says it's been tested to 300F.  So...  is this a safe choice, given that cylinders run hotter?  Yes, I assume the cover will be cooler than the head itself, but, you know...

Thanks.

[PT20J]

Should be fine. It’s silicone. Lycoming approves silicone rocker cover gaskets. Note the lower torque. The biggest problem with silicone gaskets is over-tightening which distorts the stamped cover and then it leaks.

Skip

[kortopates]

Guys,
One of my rocker cover gaskets is leaking and this is the FAA approved PN:
https://www.aircraftspruce.com/catalog/eppages/siliconecalvecover_08-01316.php
BUT...  It says it's been tested to 300F.  So...  is this a safe choice, given that cylinders run hotter?  Yes, I assume the cover will be cooler than the head itself, but, you know...
Thanks.

Those are the best gaskets and the oil cooled rocker arms don't get anywhere near that hot. But make sure you follow their install instructions else you won't be satisfied. Many over torque; especially when they see oil leakage. But the gasket and the metal needs to be clean of oil to get a good seal. So if you do get leakage it's needs to come off, all and any oil cleaned off and then properly re- installed.


Sent from my iPhone using Tapatalk

[FlyingDude]

Thank you. I'll download that SB too.

[carusoam]

Dude,

Expect there to be a °C supposed to be there…

generic Silicone rubber has a very high melt temp… even 300°C is probably a low number…

So Aviation specific silicone rubber may be in the 450°C range…

One would have to get data from the manufacturer to be more specific…

PP thoughts only, not a polymerist….

Best regards,

-a-

[carusoam]

5 minutes ago, GEE-BEE AEROPRODUCTS said:

With fiberglass 550 Temp

Quality is no cheap

when in doubt read the milspec of the material.

I use material that exceeds the original temp range .

°C Guy?   (If you want to cut and paste…  °F, )

-a-

[jetdriven]

On 7/17/2014 at 4:52 PM, Mooneymite said:

Two choices:  Gaskets that will eventually leak, silicone.  

There FIFY !