Checking valve clearance at two crankshaft positions
1. Check TDC position of piston in cylinder 1 side A:
• When the rocker arms are relieved on cylinder 1 side A, the piston is at firing TDC.
• When the rocker arms are loaded on cylinder 1 side A, the piston is at overlap TDC.
2. Check valve clearance with engine cold (at max. 40 °C):
• Inlet (I) = 0.3 mm;
• Exhaust (X) = 0.4 mm.
3. Check all valve clearances at two crankshaft positions (firing TDC and overlap TDC) according to the table
below.
4. Use feeler gauge to determine the distance between valve bridge and rocker arm.
5. If the deviation from the reference value exceeds 0.1 mm, adjust valve clearance.
Diagram for 12V/16V engines (two crankshaft positions)
Position Cylinder 1 2 3 4 5 6 7 8 9 10
12V
Firing TDC in cylinder A1 Side A I X I – – X I – – X – –
Side B I – – – – X I – I X – X
Overlap TDC in cylinder A1 Side A – – – X I – – X I – I X
Side B – X I X I – – X – – I –
16V
Firing TDC in cylinder A1 Side A I X – X – X I – – X I – – – – –
Side B I – – X – – I – I X I – I X – X
Overlap TDC in cylinder A1 Side A – – I – I – – X I – – X I X I X
Side B – X I – I X – X – – – X – – I –
I
Inlet: Inlet valve adjustment permitted
X
Exhaust: Exhaust valve adjustment permitted
–
Valve adjustment not permitted
Table 13: Valve clearance adjustments
Adjusting valve clearance
1. Loosen locknut (1) and unscrew adjusting
screw (2) by a few threads.
2. Insert feeler gage between valve bridge and
rocker arm (3).
3. Readjust adjusting screw (2) so that the feel-
er gauge just passes through the gap.
122 | Valve Drive | MS15054/03E 2018-07
TIM-ID: 0000060301 - 002
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