928, 928S, 928 S4 Model

This technical information replaces all previous instructions in repair publications concerning the tightening of the cylinder heads on the 928, 928S and 928 S4.

First Version

From Model introduction 1978 up to 1983 models engine numbers:

81 D 0812 - M 28/19 manual transmission 81 D 5829 - M 28/20 automatic transmission



Cylinder head studs black-grey color short threads (A in Picture 1).
Tightening Specifications:

Step 1: 20 N-m (15 ft. lbs.)
Step 2: 50 N-m (37 ft. lbs.)
Step 3: 90 N-m (66 ft. lbs.)



Important:

Tightening sequence must be kept for each step (Picture 2). Bearing surface of the cylinder head nuts and threads must be lightly coated with oil. Never use lubricants between washer and surface on the cylinder head. Washers must not turn while tightening. Create a reference mark if necessary.
Cylinder Head Gaskets

4.5 1 engine types M 28/03 and 04, M 28/13 to 16

Part Number Right side 928 104 371 11 Part Number Left side 928 104 372 11

4.7 1 engine types M 28/19 and 20

Part Number Right side 928 104 361 06 Part Number Left side 928 104 362 06

Cylinder Head Nuts

Part Number 999 076 028 02

Washers

Part Number 928 101 301 02



Second Version

From 1983 Models beginning with engine numbers:

81 D 0813 - M 28/19 manual transmission 81 D 5830 - M 28/20 automatic transmission 81 F 0050 - M 28/43 32 valve manual trans. 81 F 0560 - M 28/44 32 valve automatic trans.

Cylinder head studs gold-yellow color longer threads (N in Picture 1).

Tightening Specifications Torque Angle Method:

Step 1: 20 N-m (15 ft. lbs.)
Step 2: 90 degrees (1/4 turn)
Step 3: 90 degrees
Step 4: 90 degrees

Important:

First version studs (A in Picture 1) were used in production from July 21, 1983 to September 6, 1983 (1984 Model cars). Engine Numbers:

81 E 00097 - 00113 M 28/19 manual trans. 81 E 05194 - 05307 M 28/20 automatic trans.

When repairing these engines, it is especially important to remember that cylinder head tightening specifications from first version are applicable.

However, if new studs (gold-yellow) have been installed on older engines, the torque angle tightening method is applicable.






Important:

Tightening sequence must be kept for each step (Picture 2 - 16 valve, Picture 3 - 32 valve). Bearing surface of the cylinder head nuts and threads must be lightly coated with oil. Never use lubricants between washer and surface of the cylinder head. Washers must not turn while tightening. Create a reference mark if necessary.
Cylinder Head Gaskets

928S 16 valve engines

Part Number Right side 928 104 361 06 Part Number Left side 928 104 362 06

928S 32 valve engines

Part Number Right side 928 104 367 02 Part Number Left side 928 104 368 02

Cylinder Head Studs

Part Number 928 101 187 06 (193 mm) Part Number 928 101 186 04 (142 mm)
Part Number 999 076 028 02

Washer

Part Number 928 101 301 02

Note:

New cylinder head nuts (12 mm high) must be used for each repair in conjunction with the torque angle tightening method, even on older engines.
Third Version

928S engines with hexagon head bolts from April 1986 engine numbers:

81 G 00705 M 28/43 manual transmission 81 G 06827 M 28/44 automatic transmission

Tightening Specifications Torque Angle Method:

Step 1: 20 N-m (15 ft. lbs.)
Step 2: 90 degrees (1/4 turn)
Step 3: 90 degrees



Important:

Tightening sequence must be kept for each step (Picture 4). Bearing surface of the cylinder head bolts and threads must be lightly coated with oil. Never use lubricants between washer and surface of the cylinder head. Washers must not turn while tightening. Create a reference mark if necessary.
Cylinder Head Gaskets

928S 32 valve engine

Part Number Right side 928 104 367 02 Part Number Left side 928 104 368 02

Cylinder Head Bolts

Part Number 928 101 231 00 - M 12 x 180 Part Number 928 101 233 00 - M 12 x 130

Washers

All engines up to 1986 models

Part Number 928 101 301 02 (25.8 mm dia.)

From 1987 models

Part Number 928 104 229 00 (27.7 mm dia.)

Note:

Hexagon head bolts can also be installed in older engines. Threads in engine block must be cleaned when replacing studs with bolts. Torque angle tightening method in three steps is also applicable to older engines in conjunction with hexagon head bolts. Hexagon head bolts can be reused in repairs.



New washer, Part Number 928 104 229 00 may not be used on engines before 1987 model year (see sketch).