Composite Fiber gasket material has internal micro gas pockets. Depends on the
quality and repeatability of the original gasket material. When heated the
gas expands and seeps out from areas of least resistance. Perhaps after a few
heat / cool cycles all those internal gas pockets that were present when New
have been vacated. The gasket then creeps upon itself and becomes
imperceptibly thinner. Hence the original axial tension is now reduced.
Perhaps some parts of the gasket are more inhomogeneous than others and leads
to a mismatch in "torque".
That's the nature of an inhomogeneous materials.
Anyways that's how I put it together.
Best
Mordy
MDunst Headgasket.com 626.358.1616
Fax 626.628.3777
Triple R Munitions, Inc 626.201.9471
T FFL 6,7 SOT 2
On Tuesday, September 19, 2017, Scott Janzen via Fot <fot at autox.team.net>
wrote:
I?m adjusting valves after the last race weekend. For whatever reason, I put
the torque wrench on a couple of the head bolts - and found maybe 90 degrees of
movement on the few nuts I checked.
I run a Payen head gasket - composite with a metal ring at the combustion
chamber.
Should I:
loosen one nut at a time, lube with moly as provided by ARP, and retorque to
ARP spec;
tighten from the current position to ARP spec (75 ft-lb)
do nothing
The engine has probably four race weekends on it. I can honestly say I have
never re-torqued Payen gaskets before, but I have also re-checked the torque on
other gaskets and not found any movement.
_______________________________________________
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http://www.fot-racing.com
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