Torque GM LT1 head bolts ?
Thread Starter
Pro
Joined: Oct 2004
Posts: 510
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From: Pipe Creek TX
Torque GM LT1 head bolts ?
I have not come across this before ; can the new style GM head bolts be torqued to 65 ft. lbs. ; or can they only be gauged as per GM spec?
Nobody in the engine thread answered this question.
Nobody in the engine thread answered this question.
Melting Slicks
Joined: Jul 2003
Posts: 2,140
Likes: 0
From: Cincinnati Ohio
I cant help you with the GM bolts..... I used ARP head bolts.....I torqued them down to 80 ft-lbs with a good coating of oil (mobil 1). I did not blow a head gasket again over the summer 
number 7 started sucking coolant on the previous owner, and then on me after a year of my driving. Not anymore
To the Top
edit......Yes the heads were checked for warpage....there was none
number 7 started sucking coolant on the previous owner, and then on me after a year of my driving. Not anymore
To the Top
edit......Yes the heads were checked for warpage....there was none
Le Mans Master
Joined: Jan 2002
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From: Jenison MI
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St. Jude Donor '06
The last heads I did was on a 78 TA and I want to say it was like 95#.
65# just seems a little low to me. I can look tonight when I get home if no one else chims in...
65# just seems a little low to me. I can look tonight when I get home if no one else chims in...
Thread Starter
Pro
Joined: Oct 2004
Posts: 510
Likes: 5
From: Pipe Creek TX
I did not explain this correctly.
These GM new LT1 bolts do not have a torque spec. GM has some kind of gauging spec. by how far it twists after head contact or something like that.
My question is : can these be tighten with a torque wrench; and if so ; what ft. lbs.?
These GM new LT1 bolts do not have a torque spec. GM has some kind of gauging spec. by how far it twists after head contact or something like that.
My question is : can these be tighten with a torque wrench; and if so ; what ft. lbs.?
Le Mans Master
Joined: Jan 2002
Posts: 5,556
Likes: 0
From: Jenison MI
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06
The head bolts will stretch not so much twist. That is why you "should" always use new bolts when reinstalling the heads.
But yes you still need to torque the bolts to what they should be, using a torque wrench and done so in 3 passes.
I did a quick search and this is what I found.
http://www.bfranker.badz28.com/fbody/torquespecs.htm
Going by that it looks like 65# is right. I can look in my book tonight to see if mine says the same or not. But I'm sure it does.
But yes you still need to torque the bolts to what they should be, using a torque wrench and done so in 3 passes.
I did a quick search and this is what I found.
http://www.bfranker.badz28.com/fbody/torquespecs.htm
Going by that it looks like 65# is right. I can look in my book tonight to see if mine says the same or not. But I'm sure it does.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Originally Posted by SG4206
I did not explain this correctly.
These GM new LT1 bolts do not have a torque spec. GM has some kind of gauging spec. by how far it twists after head contact or something like that.
My question is : can these be tighten with a torque wrench; and if so ; what ft. lbs.?
These GM new LT1 bolts do not have a torque spec. GM has some kind of gauging spec. by how far it twists after head contact or something like that.
My question is : can these be tighten with a torque wrench; and if so ; what ft. lbs.?
Some will say that you can simply eyeball how far to twist the torque wrench...i.e. if the spec is X lb.ft of torque and then 90*, simply eyeball the 90*. Of course if your calibrated eyeball is off, you could be in for a surprise.
IMO, if you don't have the proper tool buy some ARP head bolts and torque to 65 lb/ft. 65 is correct for aluminum heads. The higher values are for iron heads which obviously the LT1 in a Vette doesn't use. Note that ARP, if you call them, will recommend you torque new bolts to spec, loosen, and torque the bolts to spec again a total of three times so that the bolts are properly stretched.
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Originally Posted by 96GS#007
IMO, if you don't have the proper tool buy some ARP head bolts and torque to 65 lb/ft. 65 is correct for aluminum heads. The higher values are for iron heads which obviously the LT1 in a Vette doesn't use. Note that ARP, if you call them, will recommend you torque new bolts to spec, loosen, and torque the bolts to spec again a total of three times so that the bolts are properly stretched.
Yea, what he said
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