Facing Contact Surface of Crankcase

Preceding work: Pistons, cylinder heads and crankshaft removed.





DATA
Engine 119.96
- Height A of crankcase: 245.35 - 245.45 mm
- Minimum height after required stock removal (1): 245.25 mm
- Permissible variation of parallelism of top mating surface to crankshaft center
In longitudinal direction: 0.080 mm
In transverse direction: 0.050 mm
- Permissible variation of evenness of top mating surfaces: 0.020 mm
- Averaged peak-to-valley height (Rz) of top mating surface: 0.006 - 0.016 mm
- Pressure-testing pressure:
Water chamber with air under water: 3 bar
- Chamfers of cylinder bores: 60° at 0.50 mm depth

Engine: 119.97/98
- Height W of crankcase: 228.90 - 229.00 mm
- Minimum height after required stock removal*: 228.80 mm
- Permissible variation of parallelism of top mating surface to crankshaft center
In longitudinal direction: 0.080 mm
In transverse direction: 0.050 mm
- Permissible variation of evenness of top mating surfaces: 0.020 mm
- Averaged peak-to-valley height (Rz) of top mating surface: 0.006 - 0.016 mm
- Pressure-testing pressure:
Water chamber with air under water: 3 bar
- Chamfers of cylinder bores: 60° at 0.50 mm depth

* The stock removal at the crankcase and at the cylinder head of an engine must together be not more than 0.400 mm.

NOTE: Face crankcase together with timing case cover. Always face right and left bank of cylinders by the same amount.





After facing, chamber the cylinder bores as shown in the sketch.





Chamfer cylinder bores with a suitable hand milling cutter as shown in the sketch. Equalize bottom edge of chamfer with polishing stone

If the crankcase mating surface is machined, the camshaft timing must be checked. Testing and Inspection