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VALVE CLEARANCE ADJUSTMENT
CAUTION
The cylinder head nuts must be retightened after the
first
SO-hours
of
break-in operation. and
before adjusting the valves. Make sure the engine is cold when retightening the cylinder head
nuts. Refer to the "TORQUE SPECIFICATION" section of this manual for proper tightening
specifications, page 61.
If the engine needs to be timed, refer to the ''TIMING ADJUSTMENT" section in the Technical Manual. En-
gine timing should be performed by a competent diesel mechanic.
Follow the procedure described
below
when tightening cylinder head nuts and when adjusting valves.
1. Loosen the hose clamp on the air breather pipe and remove the hose clamp and the air breather from the
rocker cover. Remove the rocker cover
bolts
and remove the rocker cover.
2. Tighten the cylinder head nuts according to the sequence shown in the Dlustratlon shown
below.
Make
sure the engine is cold when this is done. Loosen one head nut one-half tum and then tighten It
to
either
60 lb-ft, 8.3 kg-m, or to 81 N-m. Then proceed to the next head nut In the sequence numbering shown.
3. Torque the rocker shaft bracket securing nuts evenly between 12 to 15 lb-ft or 1.7 to 2 kg-m.
4. Adjust the valve clearances according to the procedures described in steps A-D. Adjust all valve clearan-
ces to 0.012 Inches (0.30 mm) while the engine is cold.
A. While facing the front of the engine, tum the engine's crankshaft clockwise so that the No 1 cylinder's
valves are in their "valve overlap'' position; that is, the period between the opening
of
the inlet valve and
the closing
of
the exhaust valve.
B. In this position, adjust the clearances of the No. 4 cylinder's valves. Tum the crankshaft as described
in step A so that the valves of the No. 3 cylinder are in their overlap position, and then adjust the No. 2
cylinder's valves.
C. Tum the crankshaft again so that the valves
of
the No. 4 cylinder are in their overlap position, and ad-
just the No. 1 cylinder's valves.
D.
Tum the crankshaft so that the valves of the No. 2 cylinder are in their overlap position, and adjust the
No. 3 cylinder's valves.
Westerbeke Diesel Engines
60
I
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