Section 04
ENGINE
Sub-Section 02
(TOP END)
040-02-7
Measure cylinder at 16 mm (5/8 in) below its top
edge.
1. Measuring perpendicularly (90
°
) to piston pin axis
A. 16 mm (5/8 in)
B. 25 mm (1 in)
The difference between these two measure-
ments should be within specified tolerance.
Ring / Piston Groove Clearance
Using a feeler gauge, check clearance between
rectangular ring and groove. If clearance exceeds
specified tolerance, replace piston.
NOTE :
Ring / piston groove clearance can
be correctly measured only on rectangular
ring which is bottom ring.
1. Feeler gauge
2. Rectangular ring (bottom)
Ring End Gap
Position ring halfway between exhaust port and
top of cylinder.
NOTE :
In order to correctly position ring in
cylinder, use piston as a pusher.
Using a feeler gauge, check ring end gap. If gap
exceeds specified tolerance, rings should be re-
placed.
1. Top of cylinder
2. Ring end gap
16, Cylinder Base Gasket
717 and 787 Engines Only
For the 717 and 787 engines, five thicknesses of
cylinder base gaskets are available for a precise
adjustment of the squish gap.
To determine gasket thickness, refer to the iden-
tification holes on the gasket.
1. Identification holes
A
1
F01D8CA
B
1
F01D0XA
1
2
F01D0OA
1
2
F01D67A
1
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