| Re: Remflex gaskets [message #310488 is a reply to message #310483] |
Thu, 17 November 2016 16:13   |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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Senior Member |
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Well, here I am.
Flexible Graphite is one of my favorite gasket materials. As Remflex does it, it has a great deal of compliance (if you have non-flat surfaces, it has a sense of humor) and it has very low creep (when a material moves under load). But all that comes at a price of very little recovery and a fragile material. Most are coated to prevent handling damage. It does usually have enough recovery to manage normal thermal expansions and other expected movement. Another problem with graphite is that if you do develop a leak, it will just blow away along the leak path and it enlarge that path rapidly.
Embossed Solid Copper is another good gasket material. Evidence that it was used in many places before the market price went through the roof in the late 60's. Even with deep embossing, it will have trouble accommodating mating surfaces that a not at all flat. They do also have very low creep and limited recovery, but the durability of the material is much higher than that of graphite. If there is a lot of thermal movement, they can out perform a graphite part. If a small leak does develop, it will stay small for a long time.
Microseal does not matter much for an exhaust gasket, but a graphite gasket does very well there.
Copper gasket that don't need microseal need no coating. (This was why the Chrysler BB head gaskets had to be coated at assembly.) If you choose to coat it, an anti-seize is the best answer, but the anti-seize I would choose (Fel-Pro C5a) may not be available any longer and it does contain lead and will foul an O2 sensor. A nickel based anti-seize will do almost as well.
So, there it is in real terms for real situations. You still have to decide what you are going to do, but now you have some reason for your choice.
Be aware that when you are installing a graphite gasket made the Remflex does them, you will be crushing the material for several turns and the torque/angle will have a very slow rise for a number of turns. This is not true of most materials and surely not of an embossed copper part. I would expect those to come from contact to full tension (sort of like torque) in about a single turn. This requires that in either case, you pay attention to what you are doing. (If your phone rings, put the wrench down.)
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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