TM 5-3805-280-24-2
Cylinder Block, Liners, Pistons and Rods
MEASURE PISTON PROTRUSION
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1. Press down on top of piston to remove oil clearances
before measuring piston protrusion.
NOTE: If JDG451 or KJD10123 are not available, a dial
indicator with magnetic base can be used to
measure piston protrusion, however, specifications
will be different.
2. Use JDG451 or KJD10123 Gauge (or use a magnetic
base dial indicator) to measure piston protrusion. Place
gauge on top of cylinder block so dial indicator can be
set to "zero" with top of block.
3. Position gauge across piston. While pressing gauge
downward, rotate crankshaft until piston is at TDC
position. Measure piston height at several positions
around the piston. If using JDG451 Gauge, piston
height must be checked at outer most diameter of
piston.
4. Piston protrusion must be within specifications to
prevent piston-to-exhaust valve contact.
5. Piston protrusion for pistons measured with JDG451 or
KJDG10123 Gauge must meet the following
specifications:
4-Cyl Standard Duty Codes 4801, 4803, 4809. 6-Cyl Standard Duty
Codes 4805, 4807.--Specification
Piston Protrusion ................................. 0.08--0.31 mm (0.003--0.012 in.)
4-Cyl Heavy Duty Code 4804. 6-Cyl Heavy Duty Codes 4808, 4810.--
Specification
Piston Protrusion ................................. 0.08--0.25 mm (0.003--0.010 in.)
6. Piston protrusion for pistons measured using dial
indicator with magnetic base must meet the following
1--Centerline of Cylinder Liner Bore
specifications:
2--Position at "TDC"
4-Cyl Standard Duty Codes 4801, 4803, 4809. 6-Cyl Standard Duty
Codes 4805, 4807.--Specification
Piston Protrusion ................................. 0.15--0.38 mm (0.006--0.015 in.)
Continued on next page
RG,10,DT7384 1911NOV971/2
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