Measuring Piston-to-Bore Clearance
Piston Detail
A
A
6 mm (0.24 in.)
NOTE: Do not use a feeler gauge to measure piston-to-
bore clearance – it will yield inaccurate
measurements. Always use a micrometer.
Before installing piston into cylinder bore, it is
necessary clearance be accurately checked. This step
is often overlooked, and if clearances are not within
specifi cations, engine failure will usually result.
Use these following procedures to accurately measure
piston-to-bore clearance:
1. Use a micrometer and measure diameter of piston 6
mm (0.24 in.) above bottom of piston skirt and
perpendicular to piston pin.
2. Use an inside micrometer, telescoping gauge, or
bore gauge and measure cylinder bore. Take
measurement approximately 63.5 mm (2.5 in.) below
top of bore and perpendicular to piston pin.
3. Piston-to-bore clearance is diff erence between bore
diameter and piston diameter (step 2 minus step 1).
Disassembly/Inspection and Service
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24 690 31 Rev. D
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