REAL Silicone Gasket Frequently Asked Questions

Q)    I have always thought one gasket was as good as another.  What is the difference between your silicone gasket vs the ones that came on my engine?
A)    Typically Lycoming uses cork for valve cover gaskets while TCM uses paper or neoprene. Both materials are obviously cheaper than silicone-which is our guess as to why they are used as tests show neither seal nearly as good or last as long as our aviation grade silicone.  Considering the volume (economics) and the fact other gasket materials may last long enough to get past the warranty period, the motivation engine manufacturers use cheaper gaskets should be obvious.

Q)    Why silicone?
A)    Simple, long term tests show AMS 3304 silicone (w/a durometer of 70 +/5) to be the absolute best material for the gaskets at hand in applications up to 400 deg F.  It was originally developed by NASA where the demands of space were critical if not extreme.  AMS silicone turned out to be a superior gasket to rubber, cork, paper, or neoprene as the demands in space were extreme in both pressure, temperature, durability, and sealing requirements.  It quickly became evident that in most applications aviation grade AMS 3304 silicone was a superior gasket material especially where "non-dimensional critical*" gasket material could be used in mating surfaces such as valve covers and transmission oil pans in automotive, and valve covers and pushrod seals in GA engines, as well as rocker and side accessory covers in motorcycles etc.   
*By "non-dimensional" we mean where the two mating components dimensions one to another isn't super critical such as valve covers where the thickness of the mating gasket under compression isn't critical relative to how far the valve cover is held away from the cylinder head itself.  Conversely, the engine case-half seam is dimensional critical as both engine case halves contain components whose dimension one to another is critical thus the compressed thickness of the gasket material is critical.  While silicone would work in a typical GA horizontal apposed engine case-half application from strictly a fluid-tight sealing point of view, silicone itself being as "pliable" as it is, it wouldn't normally provide the critical dimensional characteristics necessary for that application-hence we do not make a gasket for that application and a sealing compound and/or silk thread is typically used.

Q)    Are they FAA Approved and do they require a STC?
A)    They are FAA/PMA Approved for a direct replacement and they do not require a STC as they are a direct replacement for your OEM stock gaskets for all GA engine applications. A simple log book sign off requirement by your A&P is all that is required.

Q)    My engine is near TBO but has leaks.  Do I need to put new gaskets back on in a year or two when I have it overhauled or can your gaskets be reused?
A)    High time engines need REAL gaskets as much or more than low time engines.  Since our gaskets are meant to be reused and last the entire lifetime of the engine, it makes sense to replace your gaskets anytime. To reuse them they only need to be washed in warm water and reinstalled as they seal just as good the second, or third time around as they do when fresh right out of the box brand new!

Q)    How is your gasket better than the cork material on my Lycoming valve covers
A)    Tests show they seal much better, in fact far better than cork which doesn't come close to the performance of silicone. Cork is easily deformed and not nearly as resilient as silicone.  So when cork is depressed such as during over-torqueing on Lycoming and TCM valve covers, it is prone to leaks.  If in doubt check with your shop as we are sure they will confirm this.  Neoprene is better but still doesn't seal as good as silicone or isn't nearly as forgiving or durable as our aviation grade AMS silicone. REAL Gaskets can hold up to 40lbs of pressure for weeks or months w/out leaking.  See REAL Facts or see them on display at your next major airshow like EAA or SNF.

Q)    All engines seem to eventually leak or seep a little oil.  Why is it so important to put the best gasket on my valve covers or pushrod seals?
A)    Oil leaks are typically the only warning or precursor you will get of impending engine problems such as a cracked case, heads, or cylinder, or a oil line or other component that has developed a weak spot, defect, or fissure.  An oil leak is the first sign of a mag that is about to work loose and fall off!  It is imperative that all oil leaks are identified and tracked down to the source as soon as possible.  While leaking valve covers or pushrod seals are pesky and are a prime cause of an "oily engine" and dirty belly, they mask other problems and make it much more difficult to shops to recognize and diagnose most all other oil leaks.

Q)    How long are REAL gaskets guaranteed to work?
A)    Unlike all other such gaskets many of which have to be replaced on a regular basis and won't last until the engine TBO, REAL gaskets are designed to last the life of your engine and be reused through several engine overhauls.  In short, they are designed to be the only or last gasket you will ever buy-thus they are the cheapest gasket available in the long-run!

Q)    How much do they cost and are they more expensive than OEM gaskets?
Q)    Costs for valve cover gaskets range from under $4 each for TCM 360s (M20Ks) to $8 to $10+/- each for Lycomings.  Since they are guaranteed to last the life of the engine and not counting the cost of loss of oil wasted by leaks by other gasket materials, REAL gaskets are far cheaper and more economical in the long run than the stock cork or neoprene that commonly have to be replaced several times just to get to TBO.

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.