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Re: ARP main cap bolt torque?

PostPosted: Mon May 20, 2019 2:14 am
by 2cams70
ARP have no fasteners where you can use the angle tightening method. Angle tightening is typically only for modern engines using torque to yield fasteners. You won't obtain TTY fasteners for a Twin Cam. I doubt there would be any obtainable with imperial threads.

Re: ARP main cap bolt torque?

PostPosted: Mon May 20, 2019 9:37 am
by rgh0
Torque, angle and stretch are the 3 methods of fasteners tightening. Stretch is most accurate, torque the least with angle in between. Any bolt or stud can be loaded by any of these methods if you know the material being used and the bolted joint design. Measuring bolt or stud stretch in a blind hole is a little more difficult but can be done with ultrasonic measurement or hydraulic stretch rams or nuts.

In practice for a twink road engine using torque is fine in accordance with the manual specifications. For a race engine using stretch on the con-rod bolts is advisable but torque on the other bolts is fine.

cheers
Rohan.