Anyone torque there ARP head studs more than 80 ft lbs?
Trending Topics
#8
TECH Veteran
iTrader: (6)
Originally Posted by ls1290
Why in the world would you apply more than 65# when ARP says you should use that much
Keith
Keith
the question to ask would be "what application are you doing that you think you will need the added clamp force?"
one thing to think about, cylinders are bored with "X" amount of pressure on the deck/cylinder walls/web which is provided by a "Y" amount of preload on the bolts.....if you now go and do "Y"+"Z" preload, you will now be over the pressure which the cylinders were bored for and you will pull the bore out of round............you can't just change one thing and expect it to not change others........
#9
Teching In
Join Date: Aug 2005
Location: Toronto-Canada
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by ls1290
Why in the world would you apply more than 65# when ARP says you should use that much
Keith
Keith
But ARP's instructions call for 85lbs with oil, or 70lbs ARP lube.
#11
TECH Junkie
iTrader: (4)
you want to make sure your bolts are working to their peak?
properly clean the threads. properly lube it.. then TQ it to what the ARP specs are.
over-tightening a fastener does NOT make it "hold the head down more"
it just invites failure.
the ARP studs are actually stronger then the head the head itself will flex before properly installed ARP bolts will give. over-tightening them will not gain you anything besides increased chance of bolt failure. ESPICALLY if you're pushing enough power to bow the heads.
properly clean the threads. properly lube it.. then TQ it to what the ARP specs are.
over-tightening a fastener does NOT make it "hold the head down more"
it just invites failure.
the ARP studs are actually stronger then the head the head itself will flex before properly installed ARP bolts will give. over-tightening them will not gain you anything besides increased chance of bolt failure. ESPICALLY if you're pushing enough power to bow the heads.
#13
TECH Fanatic
iTrader: (35)
Join Date: Sep 2004
Location: Maryland/Illinois
Posts: 1,660
Likes: 0
Received 0 Likes
on
0 Posts
First disclaimer: I would follow the ARP instructions supplied with the studs. They make them and they know best how to use them.
With that said, for any fastener you will get the max clamp load by tightening (stretching) it right up to yield. Chances are you can get a little more clamp force on the studs by tightening them more than 85 ft/lbs. But, how much more you can tighten them depends on several other factors.
Bottom line: I would follow ARP instructions, but choice is yours.
With that said, for any fastener you will get the max clamp load by tightening (stretching) it right up to yield. Chances are you can get a little more clamp force on the studs by tightening them more than 85 ft/lbs. But, how much more you can tighten them depends on several other factors.
Bottom line: I would follow ARP instructions, but choice is yours.
#14
TECH Veteran
Join Date: Aug 2002
Location: Hartsdale, NY
Posts: 4,055
Likes: 0
Received 0 Likes
on
0 Posts
I used stock bolts for my H/C swap. I sprayed the bolts with silicone before installation and then realized i could not mark them with a felt tip pen for purposes of torking them to GM specs.
So I just titghted the bolts 40lbs, 50lbs, 60lbs, 70lbs and finally 75lbs. I used an inside out sequence - just like the old days....
My heads have been on for 3 years with no issues.
I was always curious about the final recommended factory tork spec for GM bolts. I assume 75lbs with silicone is about right.
Should I be loosing any sleep?
So I just titghted the bolts 40lbs, 50lbs, 60lbs, 70lbs and finally 75lbs. I used an inside out sequence - just like the old days....
My heads have been on for 3 years with no issues.
I was always curious about the final recommended factory tork spec for GM bolts. I assume 75lbs with silicone is about right.
Should I be loosing any sleep?
#17
TECH Veteran
Join Date: Aug 2002
Location: Hartsdale, NY
Posts: 4,055
Likes: 0
Received 0 Likes
on
0 Posts
does anyone know the true factory torque spec for factory head bolts,,,,,,
The tork then twist the bolt a certain number of degrees is confusing becuase it does not yield a final tork number....
The tork then twist the bolt a certain number of degrees is confusing becuase it does not yield a final tork number....
#18
TECH Fanatic
iTrader: (35)
Join Date: Sep 2004
Location: Maryland/Illinois
Posts: 1,660
Likes: 0
Received 0 Likes
on
0 Posts
The final torque spec does not matter. The whole point of a torque turn procedure is to get the proper amount of bolt stretch, not torque. I have personally checked breakaway torqe on TTY bolts and it can vary +/- 15% from the average value. Only 10-25% of the energy put it into tightening a bolt actually goes into stretching it, the rest is ate up by friction, thread imperfections, etc.