Inspecting And Repairing Gear Case, Timing Gear And Camshaft; Measuring Timing Gear Backlash; Measuring Clearance Between Idler Gear And Idler Shaft; Replacing Idler Shaft - Mitsubishi Heavy Industries SL Series Service Manual

INSPECTION AND REPAIR OF BASIC ENGINE

3. Inspecting and repairing gear case, timing gear and camshaft

3.1 Measuring timing gear backlash

Measure the backlash of the timing gears by using one of
the following two methods; measure the gear play with the
dial gauge plunger applied to a tooth flank on the pitch
circle at a right angle to the tooth axis, or measure the
clearance between gears by inserting a feeler gauge between
the gears at the tooth-to-tooth contacting area. Replace the
faulty gear pair if the limit is exceeded.
Item
Between crankshaft
gear and idler gear
Between idler gear
and valve camshaft
gear
Between idler gear
Timing
and pump camshaft
gear
gear
backlash
Between valve
camshaft gear and
PTO gear
Between pump
camshaft gear and
oil pump gear
3.2 Measuring clearance between idler gear
and idler shaft
Measure the inside diameter of the idler gear and outside
diameter of the idler shaft. Replace the idler gear or idler
shaft if the clearance exceeds the limit.
Item
Clearance between
idler gear and idler shaft

3.3 Replacing idler shaft

Press-fit the idler shaft into the cylinder block to the
dimension in the illustration.
6-8
Standard Limit
0.04 to 0.12 mm
[0.0016 to 0.0047 in.]
0.30 mm
[0.0118 in.]
0.08 to 0.19 mm
[0.0031 to 0.0075 in.]
0.07 to 0.20 mm
[0.0028 to 0.0079 in.]
Standard Limit
0.02 to 0.07 mm 0.20 mm
[0.0008 to 0.0028 in.] [0.0079 in.]
Measuring timing gear backlash
Measuring directions
Measuring
points
Measuring clearance between idler gear
and idler shaft
26.5 ± 0.5 mm
[1.04 ± 0.02 in.]
Replacing idler shaft