Quote:
Originally Posted by Railcarmover
The theory behind torquing fasteners is to place the fastener in tension,to actually stretch the fastener to yield. Grade 8 phosphate coated fasteners are the standard of the engine industry, and are used in varying dimensions and torqued to a specification predicated by the dimension.Grade 8 design is harder than grade 5,less tolerant of shear,but more tolerant of tension.
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Unless otherwise noted, best tension for size is achieved when the bolt is stretched just below yield - unless the fasteners are designed to go above yield.
My VW TDI had four bolts which hold the engine in place. Two of these must be removed in order to change the timing belt (gotta love VW engineering!) And they are stretch bolts (about $8 apiece) and IIRC, they need to be torqued from new to like 275ft-lbs.
The area is cramped and the beam type torque wrench gives out at 150 - so that is what the old bolts got.
I never had a problem.
Joe K