Main bearing cap screw

[DosGatos]

(07-18-2019 )Hammerhead Wrote:  

(07-18-2019 )Rawze Wrote:  It is my understanding that one is designed for a 180 degree stretch,.. and one is only designed for 90 degrees. It is even stamped into the bolt head by the bolt manufacturer,.. not cummins.

That would tell me that they are of 2 different designs, rated for 2 different stretch/torque specs. + have different metallurgy. - Only way to know for sure is to get in touch with the bolt manufacturer and ask them for the interchangeability at maximum holding force, and how far to turn one vs the other before worrying about distortion or damage.

Not trying to over-think it,. but it is a critical part of the engine, and if it were my own truck, I would not rest until I had a clearer answer than simply "use this part instead of this part bla bla BS".

Can't see bolt manufacturers putting different markings on the same bolt.
I 100% agree that I'd be telling Cummins to get the correctly marked bolts, or put me in touch with the bolt mfgr to get some documentation confirming metallurgy/stretch/strength characteristics. An additional 90° of rotation is a significant difference in torque! I don't think I'd be comfortable using a 25 IPO a 33, nevermind double!

Understood. I'll call cummins tomorrow. The head is 300ftlb plus 90 degrees. The main is 110ftlb plus 180 degrees. Which is the greater final torque?