Adjusting Timing
(Camshafts with Hexagon Head Mounting Bolts for Sprocket) Basic Setting
1. Turn crankshaft until mark Z 1 on pulley is aligned with joint of crankcase or stripe on fan housing.
2. Position both camshafts so that punch marks face up. Engine has its basic setting (cylinder no. 1 = TDC and cylinder no. 4 = overlap) by adjusting mark Z 1 on pulley to joint and punch marks on camshafts to face up.
3. In the position described above on bore in the sprocket will be exactly aligned with a bore in the sprocket flange. Insert a locating pin in these exactly aligned bores.
4. Tighten hexagon bolts for sprockets finger tight hold with Special Tool P 9191.
Fine Adjustment
1. Check valve clearance and, if necessary, adjust exactly to 0.10 mm with Special Tool P 213. ' Exact valve clearance for intake valves of cylinders no. 1 and 4 is sufficient for timing adjustments.
Note
Should one of the camshafts be turned out of basic setting position, proceed as follows, Remove locating pin from camshaft in basic setting position so that it cannot turn during the following adjustment. Turn mislocated camshaft to basic setting position (punch mark faces up) with Special Tool 9191. Then remove sprocket mounting bolt and locating pin, and turn crankshaft to mark Z 1 again.
2. Pre-load timing chains. Note
To avoid damage on chain tensioner housing, it is not permitted to pre-load timing chains with a screwdriver. Supporting the screwdriver on the chain tensioner housing could deform the latter and cause seizure of the aluminum piston. Only use Special Tool 9182 for pre-loading.
Left Camshaft Adjustment (Cylinder No. 1 )
3. Mount dial gauge on stud of camshaft housing with Special Tool P 207. Set dial gauge to zero on spring retainer of intake valve for cyl. no. 1 with valve closed and approx. 10 mm pre-load.
4. Now slowly turn crankshaft clockwise from Z 1 (TDC) by about 1 turn and observe dial gauge at same time.
Continue turning until the mean value of the adjusting tolerance, e.g. 0.10 mm valve lift (for 930/16 engine), is reached.
|
Engine 930/16 |
1. 4 - 1.7 mm |
|
Ideal value |
1.55 mm |
5. Unscrew and remove mounting bolt on left sprocket and pull out locating pin with Special Tool P 212.
6. Turn crankshaft accordingly until mark Z 1 on pulley is exactly aligned with joint of crankcase or stripe on fan housing.
7. Install locating pin again and tighten bolt finger tight, while holding.
8. Turn crankshaft clockwise two turns (720°) and recheck setting. Indicated vaiue should be within tolerances.
9. Tighten bolt of left camshaft to final torque of 120 Nm (86 ft lb), having a 2nd person hold with Special Tool P 9191.
Right Camshaft Adjustment (Cylinder No. 4)
1. Set cylinder no. 4 to TDC (cyl. no. 1 overlaps).
2. Repeat adjusting procedures described in points 3 through 9 on cylinder no. 4.
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