Engine >> CYLINDER BLOCK SPECIFICATIONS

Engine >> CYLINDER BLOCK SPECIFICATIONS

Cylinder Block Specifications On
Mercedes Benz 300D Engines

AERA members are advised to observe the following cylinder block specifications when remanufacturing Mercedes Benz 300D engine #OM617-912.

The cylinder block has a standard bore diameter of 3.5787 (90.90mm) for cylinders two through five and 3.5791 (90.91 mm) for cylinder number one. This engine also uses dry sleeves in each cylinder bore which should be installed flush with the deck surface of the block. Standard repair sleeves are readily available through aftermarket suppliers.

Piston protrusion is .020-.035 (.50-.90 mm) measured from the deck surface to the top of the piston for all engines. Piston-to-wall clearance is .0021-.0028 (.053-.071 mm) for cylinders numbers two through five and an additional .0004 (.01 mm) for the front cylinder. Measure the piston at it's largest diameter near the bottom of the skirt. OE piston suppliers and some aftermarket suppliers stamp the piston diameter, oversize amount and recommended piston clearance on the top of the piston.

Turbocharged engines have variations in piston clearance depending upon engine application, year and accessories for that particular vehicle, consult the OE manual.

The cylinder block deck height is measured from the oil pan rail to the deck of the block and should be 9.547-9.563 (242.5-242.9 mm).

The main bearing housing bore diameters are 2.9331-2.9338 (74.500-74.519 mm) with the main bearing cap bolts torqued to 65 ft. lbs.

The AERA Technical Committee

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