Westerbeke 5.0KW BCG-60Hz Service Manual page 28

PISTONS AND CONNECTING RODS
NOTE: See Crankshaft/Bearing section for measuring the oil
clearance with a Plastigauge.
Use a rod aligner to check the connecting rod for bend and
twist.
CONNECTING ROD BEND LIMIT D.DD4in (D.OSmm)
CONNECTING ROD TWIST LIMIT D.004in (0.1mm)
CONNECTING ROD BIG END TO CRANKSHAFT SIDE CLEARANCE
Standard 0.0039 - D.DD9Sin (0.10 - D.2Smm)
CONNECTING ROD CENTER LENGTH
Standard
4.0138 - 4.D178in (101.9S -1D2.0Smm)
ASSEMBLY
Piston Connecting Rod, Piston
Using the special tool (pin setting base) assemble the
piston and connecting rod and press-in the piston pin. First,
install the piston pin into the special tool,
GUIDE A
PUSH
ROD
Set up the piston and connecting rod on the piston pin setting
base. Make sure that the front marks are facing up. Apply
engine oil to the outer circumference of the piston pin and
insert the pin, Guide A and the push rod (assembled) into the
piston and connecting rod.
Using a press, load the push rod top end and press-fit the
piston pin in the connecting rod. The piston pin is press
fitted in the specified position by
press-fitt~ng
the Guide A
bottom end surface until it is seated on the bottom surface of
the base.
If
the press-fitting load is out of the specification,
replace the pin (piston assembly) or connecting rod, or both.
PISTON PIN PRESS-FITTING LOAD 1102 - 33071bs (SDDD -15DONm)
Oil Ring
Assemble the oil ring spacer into the piston ring groove.
Then, after assembling the upper side rail, assemble the
lower side rail.
NOTE: There is no difference between the upper and lower
m
SIDE
RAIL
side rails or the spacers. //~~/-
~~.,....,.-
'---.J-1~
SPACER
The chart below identifies the color coding on new spacer
and side rails according to size.
SPACER AND SIDE RAIL CODING
SIZE Color Identification
S.lO.
D.DD98in (O.2Smm) Oversize Two Blue LInes
D.D197in (D.SDmm) Oversize One Red Line
O.029Sin (0.7Smm) Oversize Two red lines
0.D394in (1.DDmm) Oversize One Yellow Line
Install the three-piece oil ring in the piston. Then, make
certain the side rails move smoothly in both directions. The
side rail my be easily installed by pushing it in with your
finger after fitting the one end over the piston groove. Do not
use an expander ring on the oil ring.
END OF SIDE RAil
Piston Rings
Use a piston ring expander and install the piston rings with
the marker and size marks facing up toward the piston top.
Notice the difference in shapes between No.1 and No.2 ring.
f..---...,/-"
PISTON RING
~~1I2PISTONRING
Engines & Generators
21