In Reply to: No, I am not aware of this. (more) posted by Jim Ross on February 26, 2000 at 00:01:29:
Keeping in mind that BMW's seem to have "use once" bolts or studs that are tightened to the point of plastic deformation. I think this reduces the possibility of loosing significant tension as the fastener is more elastic than otherwise.
It makes sense on a race engine but should not be necessary on a production engine.
: I am sure that a re-torque on the head bolts is a good thing to do. I just never thought to do it until you brought up the subject. This is something we did on new or rebuilt american enignes after the first run in period.
: The torque sequence is to start in the middle and work your way out in concentric circles until the last outer head bolt is torqued (use your imagination to see the circular pattern). You need to look up torque spec's for your particular motor.
: I imagine that once the head gasket is going then you have no choice but to replace it. With these motors lasting so long, did those owners think to re-torque their head bolts?
: I would be interested in what others think about this. Jim
: : I have been told that "the head bolts lose their 'pre-loading' as the gasket area around them softens with age. Once the seepage occurs, re-squeezing the gasket by 'snugging' the bolts may help. Done correctly it won't hurt."
: : Does anyone know the proper "RETORQUE" procedure?
: : Has anyone done this before?