[Supras] ARP torque; fuel pressure gauge

[Hacker J]

Bernie,

I think you mean the elastic region.  

I assume these are ARP studs. If so, the latest APP docs I have recommend 80 ft-lbs with ARP moly lube to achieve 75% of fastener yield strength. For the ARP *bolts* they further recommend to derate another 12% for aluminum applications due to higher thermal expansion.  However, the derating is not mentioned in the *stud* docs, which I find odd.

For the fuel pressure gauge, my solution was to tap and install a VOLVO OEM fuel system schraeder valve into the fuel rail. This valve allows a handheld gauge to be attached easily when a pressure reading is needed, and then removed during normal operation when you don't need it.

Jon
90T


----- Original Message ----


Brian, Jeoff:

    From ARP, torquing to 85 lb-ft produces stress which is 80-85% of 
yield.  So that recommended torque is still in the plastic region. 

    Also, wrote about fuel pressure gauge last night.  Fatigue of the 
bourdon tube is the only event which should cause leakage.
  Nonetheless, 
next time I have the intake cam cover off, I'm going to repipe it with
 a 
1/4 turn valve, since the cam cover prevents the gauge from being 
removed (in top of fuel rail 2/3 of the way back, bottom connected, 
tilted slightly backwards for ease of reading.  I have a modified stock
 
FPR which works fine.

       Bernie







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