Cylinder Head Assembly: Service and Repair

INSTALLING CYLINDER HEADS

Use torquing by degrees of turn method to torque cylinder heads.

Note: The earlier torque-controlled method of tightening the cylinder-head bolts has been replaced by the method of torquing by degrees of turn. The method of torquing by degrees of turn applies to repairs on all 911 Carrera engines (84 models onward). Cylinder-head nuts, Part No. 901 104 382 02 must always be used. The new nuts are yellow passivated, the earlier versions were grey.

Notes on assembly

1. Apply a thin coat of Optimoly HT to thread of crankcase studs.
2. Install cylinder heads.
3. Install washers
4. Apply a thin coat of Optimoly HT to contact surface of cylinder head nuts and tighten as follows:






Two-stage tightening:
Stage 1: 15 Nm (11 ft lb) in specified sequence
Stage 2: 90° ± 2° in same sequence