1. Starting with the bottom ring, install the compression
rings with tool J 8128 as shown in Fig. 4. To avoid
breaking or overstressing the rings, do not spread them
any more than necessary to slip them over the piston.
Refer to Fig. 16 for ring identification and location.
2. Stagger and ring gaps around the piston.
OIL CONTROL RINGS
Refer to Fig. 16 for the type and location and install the
oil control rings as follows:
1. Install the ring expanders in the oil control ring
grooves in the piston skirt. When installing the oil
control rings, use care to prevent overlapping the ends
of ring expanders. An overlapped expander will cause
Fig. 14 - Measuring Piston Ring Gap
the oil ring to protrude beyond allowable limits and will
result in breakage when the piston is inserted in the ring
A two-piece oil control ring is used in both oil ring
compressor during installation in the cylinder liner. Do
grooves in the pistons for all current engines with N75 or
not cut or grind the ends of the expanders to prevent
overlapping. Cutting or grinding the ends will decrease
the expanding force on the oil control rings and result in
All new piston rings must be installed whenever a piston
high lubricating oil consumption.
is removed, regardless of whether a new or used piston
or cylinder liner is installed. Refer to the parts catalog or
NOTE: When peripheral abutment type ring
microfiche to select the current piston rings for a
expanders are used, install them with the legs of
the free ends toward the top of the piston. With
the free ends pointing up, a noticeable
Insert one ring at a time inside of the cylinder liner and
resistance will be encountered during installation
far enough down to be within the normal area of ring
of the piston if the ends of the expander are
travel. Use a piston skirt to push the ring down to be
over-lapped and corrective action can be taken
sure it is parallel with the top of the liner. Then measure
before ring breakage occurs.
the ring gap with a feeler gage as shown in Fig. 14.
If the gap on a compression ring is insufficient. it may
be increased by filing or stoning the ends of the ring.
File or stone both ends of the ring so the cutting action
is from the outer surface to the inner surface. This will
prevent any chipping or peeling of the chrome plate on
the ring. The ends of the ring must remain square and
the chamfer on the outer edge must be approximately
Check the ring side clearance as shown in Fig. 15.
Install Piston Rings
NOTE: Lubricate the piston rings and piston
Fig. 15 Measuring Piston Ring Side Clearance
with engine oil before installing the rings.