Isuzu 4JA1 Workshop Manual page 55

INJECTION TIMING ADJUSTMENT
(4JA1T(L) only)
1. Check that the notched line on the injection pump
2. Bring the piston in the No. 1 cylinder to TDC on the
Note:
Check for play in the No. 1 intake and exhaust valve
push rods.
If the No. 1 cylinder intake and exhaust valve push
rods have play, the No. 1 piston is at TDC on the
compression stroke.
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3. Disconnect the injection pipe from the injection pump
4. Remove one bolt from the distributor head.
5. Install the adapter set, togather with static timing
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6. Rotate the crankshaft to bring the piston in the No. 1
7. Set the timing gauge needle to zero.
8. Move the crankshaft pulley slightly in both directions to
ENGINE MECHANICAL 6A – 33
flange is aligned with the front plate or the timing gear
case notched line.
compression stroke by turning the crankshaft until the
crankshaft pulley TDC line is aligned with the timing
mark.
gauge.
The probe of the gauge should be depressed inward
approximately 2 mm (0.079 in).
Static Timing Gauge: 5-8840-0145-0 (J-28827)
Adapter Set: Static Timing Gauge: 5-8840-2834-0
cylinder to a point 30 - 40° BTDC.
check that the gauge indication is stable.