Checking and Adjusting Valve Clearance
RG13749-UN-11NOV04
Flywheel Housing Timing Holes
A - Timing/Rotation Hole
B - Timing Pin Hole
CAUTION: To prevent accidental starting of engine while performing
valve adjustments, always disconnect NEGATIVE (—) battery terminal.
IMPORTANT: Valve clearance MUST BE checked and adjusted with
engine COLD.
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Remove rocker arm cover and crankcase ventilator tube.
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IMPORTANT: Visually inspect contact surfaces of valve tips,
bridges and rocker arm wear pads. Check all parts for excessive wear,
breakage, or cracks. Replace parts that show visible damage. Rocker arms that exhibit excessive valve clearance should be
inspected more thoroughly to identify damaged parts.
Remove plastic plugs or cover plate from engine timing/rotation
hole (A) and timing pin hole (B).
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NOTE: Some engines are equipped with flywheel housings which
do not allow use of an engine flywheel rotation tool. These engines
with straight nose crankshafts may be rotated from front nose of engine,
using JDG966 Crankshaft Front/Rear Rotation Adapter.
Using JDE83 or JDG820 Flywheel Turning Tool, rotate engine flywheel in running direction
(clockwise viewed from front) until No. 1 (front) cylinder is at TDC
compression stroke. Insert JDG1571 or JDE81-4 Timing Pin in flywheel.
If No. 1 cylinder rocker arms are loose, the engine is at No.
1 TDC compression.
If No. 1 cylinder rocker arms are not loose, rotate engine
one full revolution (360°) to No. 1 TDC compression.
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RG13809-UN-07DEC04
Adjusting Valves
A - Adjusting Screw Jam Nut
B - Feeler Gauge
Adjust valves to specifications below using the appropriate
valve clearance adjustment procedure as outlined in the following
below. Loosen the jam nut (A) on rocker arm adjusting screw. Turn
adjusting screw until feeler gauge (B) slips with a slight drag. Hold
the adjusting screw from turning with screwdriver and tighten jam
nut to specifications. Recheck clearance again after tightening jam
nut. Readjust clearance as necessary.
Item | Measurement | Specification |
Intake Valve Clearance Adjustment (Rocker Arm-to-Bridge) (Engine
Cold) | Clearance | 0.46
mm (0.018 in.) |
Exhaust Valve Clearance Adjustment (Rocker Arm-to-Bridge) (Engine
Cold) | Clearance | 0.53
(0.021 in.) |
Rocker Arm Adjusting Screw Jam Nut | Torque | 27 N·m (20 lb-ft) |
NOTE: While rocker arm cover is removed, test glow plugs. (See
following procedure.)
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Install rocker arm cover and crankcase ventilator tube.
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Reconnect battery terminal.
6-Cylinder Engine:
RG17725-UN-04OCT10
Valve Adjustment
A - Front of Engine
B - No. 1 Piston TDC Compression
C - No. 6 Piston TDC Compression
E - Exhaust Valve
I - Intake Valve
NOTE: Firing order is 1-5-3-6-2-4.
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Lock No. 1 piston at TDC compression stroke (B).
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Adjust valve clearance on No. 1, 3 and 5 exhaust valves and
No. 1, 2, and 4 intake valves.
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Turn crankshaft 360°. Lock No. 6 piston at TDC compression
stroke (C).
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Adjust valve clearance on No. 2, 4 and 6 exhaust valves and
No. 3, 5, and 6 intake valves.
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JR74534,0000262-19-20130724
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