Specifications
PISTON PIN—REMOVAL
(1) Secure connecting rod in a soft jawed vice.
(2) Remove 2 clips securing piston pin.
(3) Push piston pin out of piston and connecting
rod.
PISTON RING—REMOVAL
(1) ID mark on face of upper and intermediate pis-
ton rings must point toward piston crown.
(2) Using a suitable ring expander, remove upper
and intermediate piston rings (Fig. 96).
(3) Remove the upper oil ring side rail, lower oil
ring side rail and then oil ring expander from piston.
(4) Carefully clean carbon from piston crowns,
skirts and ring grooves ensuring the 4 oil holes in
the oil control ring groove are clear.
PISTON RING FITTING
(1) Wipe cylinder bore clean. Insert ring and push
down with piston to ensure it is square in bore. The
ring gap measurement must be made with the ring
positioning at least 12 mm (0.50 in.) from bottom of
cylinder bore. Check gap with feeler gauge. Top com-
pression ring gap .25 to .50mm (.0098 to .0196 in.).
Second compression ring gap .25 to .35mm (.0098 to
.0137 in.). Oil control ring gap .25 to .58mm (.0098 to
.0228 in.).
(2) If ring gaps exceed dimension given, new rings
or cylinder liners must be fitted. Keep piston rings in
piston sets.
(3) Check piston ring to groove clearance (Fig. 98).
Top compression ring gap .08 to .130mm (.0031 to
.0051 in.). Second compression ring gap .070 to
.102mm (.0027 to .0040 in.). Oil control ring gap .040
to .072mm (.0015 to .0028 in.).
PISTON RINGS—INSTALLATION
(1) Install rings on the pistons using a suitable
ring expander (Fig. 99).
(2) Top compression ring is tapered and chromium
plated. The second ring is of the scraper type and
must be installed with scraping edge facing bottom of
the piston. The third is an oil control ring. Ring gaps
must be positioned, before inserting piston into the
liners, as follows (Fig. 101).
(3) Top ring gap must be positioned at 30 degrees
to the right of the combustion chamber recess (look-
ing at the piston crown from above).
Fig. 95 Piston Assembly
Fig. 96 Piston Rings—Removing and Installing
Fig. 97 Ring Gap Measurement
WJ ENGINE 9 - 47
REMOVAL AND INSTALLATION (Continued)