Torque Angle Explanation

[wstr75]

Was recently reading a thread about 328i N52/N51 motors having a serpentine bracket requiring periodic replacement because of the bracket eventually bending from metal stress over time. In the serpentine bracket idler replacement steps was a Torque Angle to 90 degrees wrenching requirement AFTER screwing the bolt down to a prescribed torque value. I read the thread and did not know what torquing to an angle of 90 degrees meant.

Here is the explanation:
https://user.xmission.com/~kd7olf/torque.html

Here is a Youtube showing how to use a torque angle gauge:
https://www.youtube.com/watch?v=8WohM6pt58I

[SaltyNC]

I will be doing rod bearings on my Z4M soon. It uses the same engine as the E46 M3, the S54 engine. Using BMW bolts requires tightening the connecting rod bolts to 5 Nm, then 30Nm, then angle torquing to 70 degrees in one continuous motion. Then, using a breaker bar, loosen the bolt one full turn and repeat the torquing procedure. Then, do it all again. Three times this has to be done per bolt to properly stretch the bolt. The number of steps gets up there when doing the 6 cyl engine.

6 cyl * 2 bolts per connecting rod = 12 bolts
12 bolts * 4 step torquing procedure * 2 times + 12 bolts * 3 step final torquing procedure = 132 steps to correctly torque the connecting rod bolts.

Whew! Some of the more expensive digital torque wrenches have an angle torque feature built into them.

Salty

[WOLFN8TR]

Are you using WPC treated rod bearings on the Z4M?

http://www.m3forum.net/m3forum/showthread.php?t=471874

[Reasoned1]

Very interesting and informative. Thank you!

[SaltyNC]

Are you using WPC treated rod bearings on the Z4M?

http://www.m3forum.net/m3forum/showthread.php?t=471874

I'm probably going to use BE Bearings but with BMW OE rod bolts. I was really hoping BE would come out with a specially specced ARP rod bolt with a simple torque, but their ARP bolts for the S54 are the standard ARP bolts, and after reading more threads than I care to admit, I decided the BMW OE bolts were the better choice for me doing an in-service bearing swap rather than pulling the engine where out of round condition could be checked.

Salty

[WOLFN8TR]

That's cool. I've heard good thing about BE bearings as well.

[ZHPizza]

I'm probably going to use BE Bearings but with BMW OE rod bolts. I was really hoping BE would come out with a specially specced ARP rod bolt with a simple torque, but their ARP bolts for the S54 are the standard ARP bolts, and after reading more threads than I care to admit, I decided the BMW OE bolts were the better choice for me doing an in-service bearing swap rather than pulling the engine where out of round condition could be checked.

Salty

Just saw these and wanted to let you know

http://www.m3forum.net/m3forum/showthread.php?t=595175

[SaltyNC]

Thanks. I appreciate it.

Salty