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Gordo2 Gordo2 is offline
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Join Date: Sep 2002
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ARP Rod Bolt Stretch and Torque

Quote:
Originally Posted by brighton911 View Post
...I do have a question though. You stated the ARP bolts stretch standard was: "ARP instructions call for stretch of 0.0100mm to 0.0105..."

I'm guessing you meant to say .0100 to .0105 thou. Your gauge showed 4 thou stretch which seems low for 40 lbs of torque. What torque number gave you the desired stretch?
Dave
Dave,

You are correct; the ARP measurements are in inches, not mm as I previously posted (I edited & corrected the above post). Thanks for the point out - had to laugh, I recall loosing points on tests when I made that kind of mistake in college.

I agree, 0.004" doesn't seem like much stretch for 40 ft-lbs of torque. I haven't installed the rods yet. When I do, I will install the bolts to ARP's spec for stretch length and follow up with a torque reading to see what it takes to produce the recommended stretch. Will update this post when I install.

For ref, here's a related link to some more measurements & observations I recently made on the ARP rod bolts:

Measuring ARP Rod Bolt Stretch - Micrometer vs. Stretch Gauge

Thanks,

Gordo
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Don "Gordo" Gordon
'83 911SC Targa
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