General Information

NOTE: The cylinder heads differ in the diameter ,,A'' of the exhaust ports, the basic bore ,,G'' of the exhaust valve seat rings, the different combustion chamber and the valve seat rings as well as the casting number.

The cylinder heads cannot be used in cast-iron engines as the five cylinder head bolt bores do not correspond.

Remove the cylinder heads only when the engine has cooled down. Face cylinder head mating surface only if porous or damaged. A slightly warped mating surface will adapt itself again after the cylinder heads have been tightened.

Each cylinder head is aligned and fixed with the crankcase by means of two dowel sleeves and secured to the crankcase with 18 cylinder head bolts, 6 for each cylinder bore.

The cylinder head gaskets of the engines 116 and 117 differ in combustion chamber and cylinder diameter.

The cylinder head gaskets of the engines 116.96 and 117.96 differ from those of 116.98 and 117.98 by a different hole pattern of the 5 central cylinder head bolt holes.

The cylinder head gaskets do not require retorquing.

The cylinder head bolts are no longer retightened when the engine is warm.

CAUTION: The cylinder head bolts M 10 x 165, M 10 x 90 and M 10 x 65 are 10 mm longer than for the cast-iron engines.

Since November 1982 the cylinder head bolts have been nickel-plated (chrome colored); previously phosphatized (anthracite colored). This prevents the thread flanks biting into or seizing in the aluminium crankcase. At the same time the washers of the cylinder head bolts were phosphatized (previously bright galvanized, brass colored). This measure produces more even friction when tightening the cylinder head bolts.

Production Breakpoint: November 1982
Model Engine Engine End No. Chassis end No.

107.045 116.962 011845 021251
107.046 117.962 001565 025013
126.032/033 116.963 022704 038527
126.036/037 117.963 018595 027517
126.043 116.963 022704 004655
126.044 117.963 018595 004152





If damaged threads are found when removing and installing the cylinder head, Heli-Coil threaded inserts, Part No. 000 997 58 15, should be inserted for all the cylinder head bolts of the respective bank of cylinders.

CAUTION: Clean tapped holes with compressed air before screwing in the cylinder head bolts. Newly fitted cylinder head gaskets are not leaktight until the engine has run for about 10 minutes at normal operating temperature. For this reason, do not pressure-test cooling system until swelling has occurred in the cylinder head gasket as a result of heating.