Yanmar 1GM User Manual page 89

SI:-IGLE-CYLIN DER Ei'iG I:-IES
83
Oil
ring
go.
Expa ns ion
ring
go.
5
NOTE
If
the cylinder has not been rebared, check
the gap at the bottom of the ring travel,
where the cy linder is the least worn.
2. Mea sure the ring gap with a feeler gauge as shown in
Figu re 38 . Compare the measurement with speci fications
in Table I . If the measurement is not within specification.
the rings must be replaced as a set. Check
the gap of new
rings as well. If the
gap is too small. file the ends of the
ring to correct it (Figu re 39 ).
3. Check the side clearance of the rings as shown in Fig.
UfY
40 . Place the feeler gau ge alongside the ring all the
way into the groove. If the measurement is nOI withi n
specifications (Ta ble I ), either the rings or the ring
grooves are worn. Inspect and rep lace them as required .
4 . Use a ring expander too l (Fta ur e 41) to carefully in-
sta ll the o il control ring, then the compress ion rings. The
oil ring consists oftwo pieces, the oute r ring and the inner
expansion spring. Assemb le the oil ring on the p iston so
the expa nsion spring gap is on the opposi te side of the pis-
ton from the ring end gap. See Fig ul"e 42 . The second
compression ring is tapered whi le the top compression
ring has a barrel face . The top of each compression ring is
marked and mu st face toward the piston crown.
Co nnecti ng
Rod
Inspection
Have the connecting rod checked for stra ightn ess by a
dealer or machin e shop.
Th e piston pin end of the connecting rod is equi pped
with a bushing. Refe r to Ta b le I for bushing spec ifica-
tions. If bushing replace ment is requi red, a press is neces-
sary to re move the old bushing and install a new bushing.
The o il
holes in the
bushing and connect ing rod must
al ign. Ream the bushing to obta in the desi red clearance in
Ta b le I .