Camshaft: Adjustments

ADJUSTING CAMSHAFT TIMING

(Camshafts with Bolt Mounted Sprockets)

TOOLS

I Of II:

II Of II:

Rough Adjustment





1. Turn crankshaft until mark Z 1 (middle arrow) on pulley is aligned accurately with joint of crankcase or stripe on blower housing.

930 Mark:

2. Set both camshafts with punch marks or code 930 facing up. Basic engine setting of cylinder no.1 at TDC and cylinder no.4 overlapping is given by adjusting mark Z 1 on pulley to joint and punch marks on camshafts to face up.





3. In the above mentioned position a bore in the sprocket will be precisely aligned with a bore in the sprocket flange. Insert dowel pin in these accurately aligned bores.





4. Screw on bolts for sprockets finger tight. Hold with Special Tool P9191.

Note: Apply a light coat of Optimoly HT on threads of bolts.

Note: Proceed as follows in case one of the camshafts has been turned out of basic setting position:
- Take dowel pin out of camshaft in basic setting position so that it cannot turn during following adjustment.
- Correct offset camshaft to basic setting position (punch mark or code 930 facing up) with Special Tool P9191. Then remove sprocket mounting bolt and dowel pin, and turn crankshaft back to mark Z 1.

Fine Adjustment





1. Check valve clearance or adjust to precisely 0.10 mm with Special Tool P 213. Precise valve clearance of intake valves in cylinders 1 and 4 is sufficient for adjustment of timing.

Left Camshaft Adjustment (Cyl. 1)





2. Mount dial gage on stud of camshaft case with Special Tool P 207. Set dial gage to zero with approx. 10 mm preload on spring retainer of closed cyl. 1 intake valve.

3. Now turn crankshaft slowly in clockwise direction from Z 1 (TDC) approx. 1 turn, while observing the dial gage. Turn far enough that the mean value of the adjusting tolerance is reached.

Adjusting Specification
Engine 930/20/21/26 1.1 to 1.4 mm

Ideal value: 1.25 mm

4. Unscrew and remove mounting bolt on left chain sprocket and pull out dowel pin with Special Tool P 212.

5. Turn crankshaft accordingly until mark Z 1 on pulley is aligned accurately with joint of crankcase or stripe mark on blower housing.

6. Install dowel pin again and screw on bolt finger tight, while counterholding.

7. Turn crankshaft clockwise two turns (720°) and recheck adjustment. Value read from dial gage must now be within tolerances.





8. Tighten bolt of left camshaft to final torque of 120 Nm (87 ftlb), having a second person hold with Special Tool P9191.

Right Camshaft Adjustment (Cyl. 4)

1. Set cylinder no.4 to TDC (cylinder no.1 overlaps).

2. Repeat adjusting procedures on cylinder no.4 as described in points 2 through 8 of "Fine Adjustment".