Another Head Bolt/HG Thread

slow_yota

slow_yota

Gotta Pay To Play
Feb 26, 2007
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Indiana - Florida, Depends on the time of the year
So, Im buying a n/a 1990 supra at the end of the month.
The oem HG went on it and the previous owner installed another OEM HG with original head bolts.He torqued them down to 68 ft lbs.Its been on for i think around 600 miles, Is it a good time to either retorque to to 70-75 ft lbs or upgrade the bolts to arp hardware one head bolt at a time (per tsrm of course)?

For this supra i have no crazy power plans for it, Just a decent exhaust system and a few n/a bolt ons.More of a reliable weekend cruiser and DD during the summer maybe, So ...no boost.

But I already have two sets of ARP head bolts so I thought why not..Unless the loosening of the original and reinstallation of the ARP head bolts can be bad for the HG?

Any comments or opinions are welcome.
 
Poodles

Poodles

I play with fire
Jul 22, 2006
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No, removing the bolts would upset the HG. Just retorque to the higher setting in the sequence in the TSRM for tightening.
 
B

ben1984j

New Member
Jan 18, 2009
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Ft. Collins, CO
Also, you wouldn't want to change out the bolts "one at a time" even if you used the TSRM sequence, you should never have 13 head bolts fully torqued and one at zero torque while you change it out (if that's what you meant). That's why the TSRM says to make several passes when loosening/tightening...
 
jetjock

jetjock

creepy-ass cracka
Jul 11, 2005
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Redacted per Title 18 USC Section 798
Poodles;1481678 said:
Perfectly fine to do on the 7M as they're not torque-to-yeild.
Click to expand...

Unless someone previously over torqued them.

But yeah, you're right. I reused mine on a MHG and they were still going strong 13 years later. There were never retorqued either. Torqued correctly when the head was put on and that was it...
 
hvyman

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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Fullerton,CA
i believe stock head bolts are stretch type one time use. ive reused head bolts and been fine but ive also had 1 head bolt back loose on a diff 7m(with no probs.). ive also seen techs have come backs because they didn't use new head bolts that were stretch type(but on a diff engine. please correct me if im wrong about the 7m head bolts not being stretch type.
 
CRE

CRE

7M-GE + MAFT Pro + T = :D
Oct 24, 2005
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Denver, CO
hvyman;1481871 said:
i believe stock head bolts are stretch type one time use. ive reused head bolts and been fine but ive also had 1 head bolt back loose on a diff 7m(with no probs.). ive also seen techs have come backs because they didn't use new head bolts that were stretch type(but on a diff engine. please correct me if im wrong about the 7m head bolts not being stretch type.
Click to expand...

Read the thread... sheesh. They are not TTY.

Poodles;1481854 said:
True, kinda surprised the TSRM doesn't have a length spec to check them.
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I could swear I've seen a Toyota pub with details on measuring them.... I thought it was in the TSRM... I'll have to dig through my terabytes of MKIII reference materials to see if I can find it now; unless someone else knows off the top of their head (JJ?).
 
hvyman

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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CRE;1481885 said:
Read the thread... sheesh. They are not TTY.
Click to expand...
.

i have read the thread and numerous other threads plus what i have learned working at toyota. can you pin point me to exact info on how they are not as most toyotas are?
 
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