Bolt Stretch

[98redconv]

Has anyone ever used a bolt stretch gauge while installing arp rod bolts? Im am attempting to do so now, but i can only tighten the bolt about half of what it is supposed to stretch until it becomes too difficult. I could put a pipe on the end of the wrench, but is it normal for so much force to be required? I am afraid of over tightening.

[red99camaross]

installing stretch bolts requires a dual readout torque wrench. I dont know much but i hope this helps

[1fastcamarosss11]

i'm pretty sure it is 400 lbs.


just checked.
book says 240 first pass. second pass 37 more,

[0rion]

i'm pretty sure it is 400 lbs.


just checked.
book says 240 first pass. second pass 37 more,

I believe you mean degrees and not lbs right?


The write up I saw used Katech bolts and they were torqued like 3 seperate times. Their search function sucks now so I can't find the thread but I *think* it was like 30-30-50 ft/lbs for the katechs. Call ARP and see what they recommend and go with that.

[98redconv]

Well when you are measuring stretch alone, it is a little different. The guage tells you how much the bolt is elongating by, and all you use to do the tightening is a boxed end wrench.

[m_williams]

I have done it. I used a Comp Cams rod bolt stretch gauge.

1) How are you trying to do it?

2) Do you know how to read a dial indicator?

3) Are you using the moly lube that came with the bolts? YOU MUST USE THE MOLY LUBE THAT CAME WITH THE BOLTS!

Every time I did others. I turned the rod bolt down untill it just touched the rod and then zeroed the stretch guage on the bolt. I used a torque wrench and torqued them to 40lbs and then loosened them up, then torqued them down to 40lbs again and then loosened, and then one more time to 40lbs and then loosened them up.

I would then check the bolt, and see if it had the proper stretch on it, in between .0062-.0067.... If not I would loosen it up all of the way, and then use a wrench untill I got the proper stretch.