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Location:
Brisbane
Registered:
July 2004
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7M head bolt retorque?
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Mon, 17 January 2005 08:23
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Well i've just finished a head gasket job on a 7M-GE, 
Aint she pretty? 
I've torqued the bolts down to 72 ft/lbs (as this is the number i kept hearing from everyone).
Anyway, i'm wondering what is the go with retorquing the head?
I know its a good idea to wait till 1000-1500kms or so,
Some say to back off each bolt and retighten one by one, others say not to back it off as you introduce oil, water, whatever sorts of stuff into the thread that can mess up the torque readings (??).
What is the proper technique?
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 7M head bolt retorque?
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Mon, 17 January 2005 10:21
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must undo them and retorque one by one in order as indicated in the manual
highly highly unlikely to introduced shit into the thread as the h/g should still be sealing the galleries
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Location:
Adelaide
Registered:
September 2003
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Re: 7M head bolt retorque?
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Mon, 17 January 2005 10:34
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| ed_ma61 wrote on Mon, 17 January 2005 20:51 |
must undo them and retorque one by one in order as indicated in the manual
highly highly unlikely to introduced shit into the thread as the h/g should still be sealing the galleries
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Then theoritically Ed, can you do the same by taking out the old headbolts and installing ARP ones in the same manner ?
If so, consider the job done !!!!
I would guess to torque in stages like 50 - 70 and then 90 (or whatever the ARP instructions say ?
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 7M head bolt retorque?
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Mon, 17 January 2005 10:58
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| bbaacchhyy wrote on Mon, 17 January 2005 21:34 |
| ed_ma61 wrote on Mon, 17 January 2005 20:51 |
must undo them and retorque one by one in order as indicated in the manual
highly highly unlikely to introduced shit into the thread as the h/g should still be sealing the galleries
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Then theoritically Ed, can you do the same by taking out the old headbolts and installing ARP ones in the same manner ?
If so, consider the job done !!!!
I would guess to torque in stages like 50 - 70 and then 90 (or whatever the ARP instructions say ?
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id be happy enough to do that 
make sure you follow the pattern correctly though
but dont just guess, as above, follow the instrustions exactly. each bolt also needs to go through a torque, re-torque cycle for preliminary stretch before final tensioning.
cheers
ed
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Location:
Perth W.A.
Registered:
April 2004
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Re: 7M head bolt retorque?
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Mon, 17 January 2005 12:15
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So is 72 ft/lbs the correct torque for the 7m-gte also?
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 7M head bolt retorque?
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Mon, 17 January 2005 12:37
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72ft/lbs is the maximum sustainable torque capable by the stock 7m head bolts (as measured by some yank doing a stress strain analysis ages ago)...
its commonly regarded as what you should retorque them to
ARP or other fasteners have thier own specs to follow when installing
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Location:
Brisbane
Registered:
June 2003
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Re: 7M head bolt retorque?
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Mon, 17 January 2005 13:01
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| ed_ma61 wrote on Mon, 17 January 2005 22:37 |
72ft/lbs is the maximum sustainable torque capable by the stock 7m head bolts (as measured by some yank doing a stress strain analysis ages ago)...
its commonly regarded as what you should retorque them to
ARP or other fasteners have thier own specs to follow when installing
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i did mine at 73 and they were fine!!
i didnt *undo* mine when i re-torqued it..i just tightened them up...to discover they had lost fuck all of their tightness
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Location:
tas
Registered:
June 2002
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Re: 7M head bolt retorque?
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Mon, 17 January 2005 15:28
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First time i torqued the headbolts i whent to 68ft pounds. Good thing i did as i found a couple headbolts on intake side were loose. The headgasket was just done at toyota from the previous owner ($2500!!)
A year later i did a retorque and found none of the bolts had lost any tightness from the original 68ft pounds.
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Location:
Brisbane
Registered:
July 2004
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