12 VALVE HEAD BOLT TORQUE
#1
12 VALVE HEAD BOLT TORQUE
Correct me if I'm wrong but I haven't seen any detailed threads on re-torquing the 12 valve head bolts down to handle more boost which I'm looking into as I build up the engine a little.
Here's a good article I read online from diesel power mags you can read here on torquing the bolts down. They give 2 methods of doing it and warn the reader of torquing the bolts down more than 120 ft-lbs.
The article states the Factory Cummins torque spec is around 115 ft-lbs.
However - my Chilton manual gives the stock torque spec as
66 ft-lbs +1/4 turn for the short head bolts and 90 ft-lbs +1/4 for the long head bolts.
So....
My Question: Does anyone else have experience with this? What's the true factory specs and what specs can you push the stock bolts too?
Thanks
Here's a good article I read online from diesel power mags you can read here on torquing the bolts down. They give 2 methods of doing it and warn the reader of torquing the bolts down more than 120 ft-lbs.
The article states the Factory Cummins torque spec is around 115 ft-lbs.
However - my Chilton manual gives the stock torque spec as
66 ft-lbs +1/4 turn for the short head bolts and 90 ft-lbs +1/4 for the long head bolts.
So....
My Question: Does anyone else have experience with this? What's the true factory specs and what specs can you push the stock bolts too?
Thanks
#2
12 VALVE HEAD BOLT TORQUE
I've always replaced the head bolts cause all ur gunna wind up doing is streaching them or break them. I just pulled the head off mine cause of to much boost. I'm going back with head studs and a better head gasket. Stock bolts and gasket are designed for no more than 42psi I think
#4
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i use fel-pro head gasket print-o-seal
set torque at 100
run 35 lbs boost
in 5yrs i have blown 1 gasket
i dont see how you can run studs in the back of motor due to room the only way i can get pushrods in on #6 is to remove crossmember and let tranny hit the ground
still have to fight to get them in
set torque at 100
run 35 lbs boost
in 5yrs i have blown 1 gasket
i dont see how you can run studs in the back of motor due to room the only way i can get pushrods in on #6 is to remove crossmember and let tranny hit the ground
still have to fight to get them in