torqueing the bolts instead of using degrees
Staging Lane
Joined: Apr 2020
Posts: 77
Likes: 13
From: Tx
I know this is really old but I couldn’t help myself ..I hope your engine has given ya yrs of fun ! 
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,615
From: Central Cal.
it’s not hard ,it’s easier to figure out the angle in your head than it is to go through the effort of buying a angle gauge..just cut it up like a pie or think of it as a clock using 15 mins as 90 degree ..it’s not rocket science I know this is really old but I couldn’t help myself ..I hope your engine has given ya yrs of fun !
I know this is really old but I couldn’t help myself ..I hope your engine has given ya yrs of fun !
TECH Apprentice
Joined: Nov 2016
Posts: 371
Likes: 18
From: switzerland
i guees it stould be stated clearly:
- there are regular screws that work in the elestic range and are torqued to 70-80% of yield strenght according to tables. you can torque these to a corresponding angle, which makes the procedure somewhat more accurate.
- then there are tty screws with a different metallurgy that are torqued to angle. they provide more elastic fastening. (if you were to reuse them, experimentally finding the correct angle or even torque to get to the original point, you still loose the lower part of the elastic range they have work hardened through.)
- there are regular screws that work in the elestic range and are torqued to 70-80% of yield strenght according to tables. you can torque these to a corresponding angle, which makes the procedure somewhat more accurate.
- then there are tty screws with a different metallurgy that are torqued to angle. they provide more elastic fastening. (if you were to reuse them, experimentally finding the correct angle or even torque to get to the original point, you still loose the lower part of the elastic range they have work hardened through.)
The initial torque is to draw all the parts together so there is no more slop. The turn angle is to achieve the same bolt stretch regardless of friction so all the bolts achieve a tighter variation of clamping load (this is desirable). Friction under the bolt head has a HUGE effect on final stretch and clamping load (friction of threads is much smaller effect). And I'm not just talking about oil, even material and surface coatings matter. Point is, the tightening specs are designed to keep the variation of clamping load tight which is important considering the application. It's not so important for other things but it is important for rods.
