Need help from the pro's with Stretching ARP Rod Bolts.
01-15-2013, 08:14 PM
#1
Supporting Vendor
Thread Starter
Need help from the pro's with Stretching ARP Rod Bolts.
Hi everyone,
I am doing a rebuild on my 440ci LS2 stroker.
It has Eagle Rods that had the 7/16” 8740 ARP bolts.
I am upgrading to the 7/16” 2000 ARP bolts.
I am doing the stretch method. The paper that came with the bolts
calls for .0064”-.0068“ stretch or 75 ft lbs torque. I am using the ARP lube that came with them.
At 75 lbs the stretch is about .005 and at 85 ft lbs its almost .006.
I even had my torque wrench calibrated to make sure it wasn’t off for $42 and the guy said it was dead on and didn’t need any adjustment.
My questions are:
Do I go more torque to get the needed stretch?
What the max torque I can go?
Do I need to torque (stretch) the new bolts and then loosen them and re-stretch or just
go one time?
Do I have to have the rods checked for distortion with the new bolts?
I am asking on the C5 tech also.
Thanks for your help!
I am doing a rebuild on my 440ci LS2 stroker.
It has Eagle Rods that had the 7/16” 8740 ARP bolts.
I am upgrading to the 7/16” 2000 ARP bolts.
I am doing the stretch method. The paper that came with the bolts
calls for .0064”-.0068“ stretch or 75 ft lbs torque. I am using the ARP lube that came with them.
At 75 lbs the stretch is about .005 and at 85 ft lbs its almost .006.
I even had my torque wrench calibrated to make sure it wasn’t off for $42 and the guy said it was dead on and didn’t need any adjustment.
My questions are:
Do I go more torque to get the needed stretch?
What the max torque I can go?
Do I need to torque (stretch) the new bolts and then loosen them and re-stretch or just
go one time?
Do I have to have the rods checked for distortion with the new bolts?
I am asking on the C5 tech also.
Thanks for your help!
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01-16-2013, 06:40 AM
#2
Safety Car
Did you 'pre stretch' the bolts?
ARP recommends that you torque the bolts three times prior to the final assembly and then if using the stretch method to tighten them to achieve your required stretch.
ARP recommends that you torque the bolts three times prior to the final assembly and then if using the stretch method to tighten them to achieve your required stretch.
01-16-2013, 02:56 PM
#3
Supporting Vendor
Thread Starter
Thank you!
01-16-2013, 05:27 PM
#4
Safety Car
Per the ARP catalog it says 'Whether measured by stretch or by torque, proprly pre-loading a rod bolt is essential,,,,'. Which is how I've always done it.
But then it goes on to say "However, with the introduction of ARP's new Ultra-Torque fastener assembly lubricant, cycling a new fastner before final installation becomes a 'thing of the past""
Granted, they should have been torqued down or stretched after they were installed and prior to machining the big end. The length at that time needed to be measured to compare during the final assembly.
All told, I've never had a failure with an ARP bolt that I've torqued down, but then most of those have been on moderate engines.
All else fails, call ARP 805-339-2200 they are located in Ventura
But then it goes on to say "However, with the introduction of ARP's new Ultra-Torque fastener assembly lubricant, cycling a new fastner before final installation becomes a 'thing of the past""
Granted, they should have been torqued down or stretched after they were installed and prior to machining the big end. The length at that time needed to be measured to compare during the final assembly.
All told, I've never had a failure with an ARP bolt that I've torqued down, but then most of those have been on moderate engines.
All else fails, call ARP 805-339-2200 they are located in Ventura