between the end plate, fly wheel hous-
i n g a n d t h e n e w g a s k e t a n d between
the end plate and the cylinder block).
F. R e - i n s t a l l t h e f l y w h e e l h o u s i n g a n d
the flywheel and tighten the attaching
bolts in the proper sequence and to
Then recheck
the specified torque.
the runout. If necessary, replace the
flywheel housing.
13. R e m o v e t h e b o l t s h o l d i n g t h e l i f t e r
bracket to the flywheel housing. Affix a
new gasket to the bracket, then alter-
nately tighten the bracket-to-flywheel
the bracket-to-cylinder
and
housing
head bolts, thus drawing the bracket in-
to the corner formed by the cylinder
head and housing.
F i g u r e 11B-110. Piston and
C o n n e c t i n g Rod Assembly
14. Install the oil pan.
then through the center hole in the
15. Remove the engine from the overhaul
bushing to the underside of the piston
stand and complete assembly of the en-
crown.
A portion of the oil flows along
gine.
the grooves in the bushing to lubricate
the piston pin.
CROSS-HEAD PISTON
During engine operation, gas loads push-
ing down on the piston crown are taken
directly by the piston pin and bushing.
Description
The piston skirt, being separate, is free
from vertical load distortion; thermal dis-
The cross-head piston (Figure 11B-110
tortion is also reduced as the piston
a n d Figure 11B-111 on page 11B-71) is a
As the connecting rod
crown expands.
two piece piston consisting of a crown
swings to one side during downward
a n d s k i r t . A metal oil seal ring is used
travel of the piston, the major portion of
between the crown and skirt which are
the side load is taken by the piston
held together by the piston pin. Ring
skirt.
g r o o v e s are machined in the piston crown
for
a
fire
ring a n d t w o c o m p r e s s i o n
The turbocharged engines use a 17 : 1
The crown is also machined to
rings.
compression r a t i o p i s t o n . T o a i d i d e n -
accept a 150 slipper type bushing (bear-
tification
of
a
piston,
refer
to
ing).
The piston skirt incorporates two
F i g u r e 11B-112 on page 11B-71. F i t t h e
oil control ring grooves, piston pin holes
end of the gauge between the top of the
a n d p i s t o n p i n retainer counterbores.
piston crown and the machined step be-
Equally spaced drain holes are located in
low the third compression ring groove.
the oil ring groove area to permit excess
A "GO" check identifies a piston used in
oil, scraped from the cylinder walls, to
a turbocharged engine. A space of ap-
A lubricating
return to the crankcase.
proximately 0.030" ("NO-GO") identifies
oil tube and floating nut are contained
a piston used in a naturally aspirated
inside of the piston pin. Two bolts and
engine.
spacers are used to attach the connect-
ing rod to the floating nut in the piston
NOTE
pin.
Cross-head pistons and trunk-type
Internal parts of the piston are lubri-
pistons must not be used together
cated and cooled by the engine lubricat-
The difference in
in an engine.
Oil
is
pressure
fed
up
the
ing oil.
weight of the pistons will affect
drilled passage in the connecting rod,
engine balance.
through the oil tube in the piston pin,
