Factory OE and examples of specific aftermarket specifications
By Mike Mavrigian
Applying the correct tightening values for threaded engine fasteners is critical for any engine build. Listed here are both factory OEM values, some of which involve a torque-plus-angle tightening method, and OEM and aftermarket values which require only a tightening-by-torque (or by monitoring rod bolt stretch) approach. Especially with regard to main cap bolts, cylinder head bolts and connecting rod bolts, it is imperative to follow the correct tightening procedures depending on the use of OEM bolts or aftermarket high performance fasteners. Each requires a different tightening method. These OE bolts require a torque-plus-angle method, while aftermarket fasteners require only a torque value. Also, since the OEM main cap, cylinder head and rod bolts are torque-to-yield, they should not be re-used. This also holds true for the crankshaft bolt that secures the crankshaft pulley. The OEM crank bolt is designed as a one-time use bolt and should never be re-used.