LT4 Head Bolt Torque when using AFR Head Bolts
Thread Starter
Race Director
Joined: Apr 2000
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From: Texas
LT4 Head Bolt Torque when using ARP Head Bolts
When I'm ready to reinstall my cylinder heads (ported original castings), I'll be using ARP head bolts (Jegs p/n 070-134-3601). What spec are you guys tightening traditional head bolts to? 60 lb/ft for all the bolts or 65 long bolts / 60 medium & short or ?
For those that are curious / before someone says look in the Factory Service Manual :)...the stock head bolts are torqued to 22 lb/ft. After that the long bolts are tightened an additional 80* and the medium and short bolts are tightened an additional 67* using an angle gauge on a ratchet. The stock bolts are not reusable, hence the switch and the question :)
Thanks.
[Modified by 96GS#007, 10:02 PM 1/4/2004]
For those that are curious / before someone says look in the Factory Service Manual :)...the stock head bolts are torqued to 22 lb/ft. After that the long bolts are tightened an additional 80* and the medium and short bolts are tightened an additional 67* using an angle gauge on a ratchet. The stock bolts are not reusable, hence the switch and the question :)
Thanks.
[Modified by 96GS#007, 10:02 PM 1/4/2004]
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: LT4 Head Bolt Torque when using AFR Head Bolts (96GS#007)
I used AFRs recommendations on torquing the heads down. They recommend 65 to 70 ft/lbs in 10lb increments starting at 40 ft/lbs. I have done several small blocks with aluminum heads using this method without any problems.
Thread Starter
Race Director
Joined: Apr 2000
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From: Texas
Re: LT4 Head Bolt Torque when using ARP Head Bolts (Topload)
Thanks guys. I think I'll go to 70 on all the bolts. I'm using Imp SS headgaskets that will push the CR to 11.3:1, so a little extra clamping force would be nice :D
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: LT4 Head Bolt Torque when using ARP Head Bolts (96GS#007)
My ARP directions show 60 ft/lb for aluminum heads and ARP thread sealer (needed for bottom two rows due to coolant jacket penetration although I used on all bolts for simplicity).
No gaskets blown in 5500 'easy' miles with the Impala HG combination.
:)
No gaskets blown in 5500 'easy' miles with the Impala HG combination.
:)
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: LT4 Head Bolt Torque when using ARP Head Bolts (96GS#007)
Thanks guys. I think I'll go to 70 on all the bolts. I'm using Imp SS headgaskets that will push the CR to 11.3:1, so a little extra clamping force would be nice :D
The shorter bolts require less torque to achieve the same clamping force that the longer bolts do at a higher torque reading. A shorter column stretches less.
60/75 for the top and middle rows and 55/65 for the lower row. I feel you'd be better off using 65 all around rather that to put 70 on the lower.
Remember, over-torquing can effect ring seal by distorting the cylinder walls.
Just my thoughts.
Jake
Thread Starter
Race Director
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From: Texas
Re: LT4 Head Bolt Torque when using ARP Head Bolts (JAKE)
Great point and good catch Jake! I appreciate everyone's feedback. I didn't think the effects of the bolt lengths all the thru. As No Go pointed out, ARP recommends 60 lb/ft all around. I know several that have used 65 lb/ft all around but I have to believe the bolt mfg knows what they're talking about.
Any thoughts on 60 all around Jake?
Thanks!
Any thoughts on 60 all around Jake?
Thanks!
Le Mans Master
Joined: Aug 1999
Posts: 7,339
Likes: 137
From: WilkesBarre PA
Re: LT4 Head Bolt Torque when using ARP Head Bolts (96GS#007)
Jim, I use the ARP recomendation of 60 all around, their sealant on all bolt threads, oil on the washers and under the bolt heads
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Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Re: LT4 Head Bolt Torque when using ARP Head Bolts (96GS#007)
That's REALLY the bottom line to this. Use the spec called for by the bolt manufacturer. And be sure to use whatever lubricant the company says to use to insure you get the torque spec they recommend. I should have noticed that you have ARPs stuff.
Chevy's torque recommendations, the ones you see in the service manuals, Chilton, Motors Manuals, etc., is for stock bolts.
I'm using ARPs rod, main and head bolts and I used the spec ARP said to use. I should have mentioned that before, sorry.
One thing I promised myself I'd never do is to try to commit torque specs or torque sequence to memory. Too easy to make a mistake and get it wrong. So when I saw your post I went to my GM Shop Manual for the specs there, not remembering that you have ARPs bolts.
Jake
[Modified by JAKE, 2:58 AM 1/6/2004]
Chevy's torque recommendations, the ones you see in the service manuals, Chilton, Motors Manuals, etc., is for stock bolts.
I'm using ARPs rod, main and head bolts and I used the spec ARP said to use. I should have mentioned that before, sorry.
One thing I promised myself I'd never do is to try to commit torque specs or torque sequence to memory. Too easy to make a mistake and get it wrong. So when I saw your post I went to my GM Shop Manual for the specs there, not remembering that you have ARPs bolts.
Jake
[Modified by JAKE, 2:58 AM 1/6/2004]
