IHI NIIGATA MG(L)26HLX, Instruction Manual

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SECTION
４
- DISASSEMBLY AND REASSEMBLY
4.8 CAMSHAFT AND TIMING GEAR TRAIN
４－８－０４
Camshaft drive inspection
To obtain access to the camshaft drive, remove the cam gear housing (with
governor and governor drive).
- Inspect the condition of the teeth on the cam gear and the mating drive gear
(Idler gear # 1) carefully for signs of pitting near the pitch line or other
unusual wear. A new gear (s) should be installed if damage is apparent.
- Measure the camshaft end-play with a dial indicator. If the end-play
exceeds the settled valve, a new thrust bearing should be installed.
- Measure the backlash between the cam gear and the idler gear with a dial
indicator. The backlash should not exceed the settled value.
Idler Gear Bearing Replacement
The two idler gears in the timing gear train run on back-to-back roller
bearings, as shown by Figure. In the event that problems are suspected
with these bearings, they can be removed for inspection or replacement as
follows:
- Loosen bolts
①
a few turns and tap lightly on the bolt heads
to release the shaft from the housing.
- While supporting the gear and shaft by hand, finish removing
the two bolts and remove the gear, shaft, and bearing assembly in the
through the opening housing.
- Place the assembly on a workbench, remove the snap rings
③
,
and drive the bearing from the shaft with a soft (bronze) punch.