Retorque head studs after fixing leaks?
04-08-2014, 09:14 AM
#1
Retorque head studs after fixing leaks?
Some of you may have seen my questions / problems that were posted over on ICDEDPPL's thread on the "Boating on a Budget" forum about his dyno results. Never intended to run off on a tangent, but the gist of it was that I was pressure checking my block with head studs to check for leaks, and had several studs leaking air up through the threads. I pulled the head and fixed the leaks, and torqued the studs to the recommended numbers. My question is whether or not I need to back the nuts off 1/4 turn and then retorque each nut to the recommended setting. I did this the first time because I have seen it recommended to let it sit for a few hours and then follow this procedure.
Engine is a Gen VI 454 block with AFR aluminum heads and ARP studs.
Engine is a Gen VI 454 block with AFR aluminum heads and ARP studs.
04-08-2014, 03:29 PM
#3
I have found it to be pretty tough to retorque after a heat cycle, especially since some of the head bolts are not accessible without removing rocker arms, headers, etc. I recall that retorquing some time after heads are installed allows for the gaskets and studs to "take a set" or something along those lines.
04-08-2014, 05:36 PM
#7
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The only thing retorquing them will do is burnish the threads for a clean full clamping force of the torque. I've done this several times on diesels. Retorque hot, cold after several miles etc. if you torque them down, back them off and torque again, do that process 3 times, you can go over them a year later and your torque wrench will not move at all. Done it more than once on diesel head studs that require 180 ft lbs.
Btw, that whole process is completely unnecessary on a n/a 700hp or less engine. Not enough cylinder pressure to over come the clamping force of studs in a bbc torqued in sequence.
Btw, that whole process is completely unnecessary on a n/a 700hp or less engine. Not enough cylinder pressure to over come the clamping force of studs in a bbc torqued in sequence.
04-08-2014, 05:44 PM
#8
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I talked to ARP when I installed my head studs and they said to seat the threads by torqueing and loosing a few times before final assy.Also you did put the studs in only finger tight ?
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04-08-2014, 07:03 PM
#10
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The only thing retorquing them will do is burnish the threads for a clean full clamping force of the torque. I've done this several times on diesels. Retorque hot, cold after several miles etc. if you torque them down, back them off and torque again, do that process 3 times, you can go over them a year later and your torque wrench will not move at all. Done it more than once on diesel head studs that require 180 ft lbs.
Btw, that whole process is completely unnecessary on a n/a 700hp or less engine. Not enough cylinder pressure to over come the clamping force of studs in a bbc torqued in sequence.
Btw, that whole process is completely unnecessary on a n/a 700hp or less engine. Not enough cylinder pressure to over come the clamping force of studs in a bbc torqued in sequence.
Do you still torque them 3 times when the spec is 330 ft. Lbs? Cause ill tell you what after one pass using a 5 ft pipe I'm about ready to fall out and I'll be damned if I'm gonna attempt a 2nd pass.
