Head unit: checks and adjustments
Reset the degree wheel of tool part no.
88713.0123:
the horizontal piston is at TDC in the combustion stroke and
therefore you can proceed with checking valve clearance on this cylinder head.
To measure valve clearance in the vertical cylinder, rotate the crankshaft counterclockwise through 270°. This will
bring the vertical piston at TDC during the combustion stroke that is the correct position for checking valve clearance
on this cylinder head.
Checking opening clearance (Sa) at intake/exhaust
To check opening clearance (Sa), slide a feeler gauge between opening rocker arm (B) and shim (3). Measured
clearance must be within the specified limits (Sect C1.1,
).
If the clearance measured is outside the specified limits, remove the opening shim (3) as described under paragraph
in Section N 4.4, and replace it with a suitable one to reach the recommended assembly
clearance.
Note
When performing this check and inserting the feeler gauge, pay attention to overcome rocker arm closing spring force
to take up rocker arm operating play: for this purpose, ensure that shim can rotate freely.
Note
Spare opening shims are available in 1.8 - 3.45 size: the size is punched on the shim.
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