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arp head stud torque spec

50K views 79 replies 47 participants last post by  19GSX97 
#1 ·
what is the recommented torque spec for a 1g head using arp stud?
 
#4 ·
The instructions with the 6 bolt ARP set call for 80 ft/lbs with ARP moly lube or 120 ft/lbs with 30wt motor oil.

I personally torque mine at 90 ft/lbs with the ARP moly lube. I have torqued a set as high as 120 ft/lbs with the moly lube, it doesn't hold any better and may cause damage to the cylinder head.
 
#5 ·
I go 100 ft/lbs ;) w/moly
 
#8 ·
Well, other things to consider too is if you're using loc-tite on the bolts. What kind of power you're looking to run with the engine (80 lbs wouldn't be a good choice for someone pushing 36 lbs of boost with 1600 cc injectors and nitrous oxide) Be sure to give more details about what you're planning on doing with your engine/car when you ask questions.

I've got mine at 125 after following the retorquing procedure recommended by ARP 3 times on my GT42R/T04S at 34lbs
 
#10 ·
GSXSpot said:
Well, other things to consider too is if you're using loc-tite on the bolts. What kind of power you're looking to run with the engine (80 lbs wouldn't be a good choice for someone pushing 36 lbs of boost with 1600 cc injectors and nitrous oxide) Be sure to give more details about what you're planning on doing with your engine/car when you ask questions.

I've got mine at 125 after following the retorquing procedure recommended by ARP 3 times on my GT42R/T04S at 34lbs
This is very, very wrong assuming you are using the moly.The fasteners have a certain limit and torquing beyond that limit will NOT increase the clamping strength but will only stretch and destroy the fastener. Remember, the fastener acts as a spring. What mostly determines the clamp load is the lubricant being used. No point going over 100 with Moly/ARP. If you are still lifting the head at that point, get stronger fasteners with a higher yield point like the A1's. Not cheap. ;)

Thread starter, chase the holes in the block with a tap (& clean them,) use moly lube only on the threads that the nuts go on (ie. not in block) and torque in three sequences with the last being the longest. If the studs are brand new, you MUST TIGHTEN AND LOOSEN them five times before applying final torque.

Read rule 7 before posting again please and moving this to Gen. Tech.
 
#11 ·
GSXSpot said:
Well, other things to consider too is if you're using loc-tite on the bolts. What kind of power you're looking to run with the engine (80 lbs wouldn't be a good choice for someone pushing 36 lbs of boost with 1600 cc injectors and nitrous oxide) Be sure to give more details about what you're planning on doing with your engine/car when you ask questions.
Loctite is a no no on these studs. Manufactures make guidelines and instructions for a reason.

I have run 35 psi of boost w/ a 75 shot on top of that. If the studs are properly installed with a worthy headgasket, you do your retorque before boosting the engine and don't detonate the motor the head will not lift. Thats personal experiance.
I can also say I have blown a headgasket with a 16G at 25 psi trying to run outrageous timing. I thought I could keep the head down since I ran bigger turbos and 10 more pounds of boost without incident. I was wrong the head still lifted. It doesn't matter what your torque the studs at or what fastners you use. If you detonate the motor hard enough the head will lift END OF STORY :chair:
 
#54 ·
It's a 14mm 12 point nut.
 
#22 ·
The ARP torque spec with Moly Lube is 86ft-lbs and 109 ft-lbs with 30 wt oil.

These torque specs are listed to 75% of the bolts yield strength. If you exceed the yield strength, the bolt becomes weaker. I suggest anyone asking the question of how high to torque your head studs, stick with the manufacturers recommendation. Some peoples circumstances require a higher torque value, which is why ARP's catalog says that the torque values are for general information and not intended for specific installations. As a mechanical engineer, I advise to never exceed the yield strength of the fastener. You can find formulas online to calculate where that will happen.
 
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