SERViCE MANUAL
Paragraphs 50-52
NOTE:
Two different seai rings have been used.
Measure groove diameter to determine the correct
seai ring to be instalied. If groove diameter meas-
ures 4.667-4.677 inches (118.54-118.80 mm), instali
old type (red tracers), if groove diameter measures
4.658-4.668 inches (118.32-118.58 mm), instaii new
type (goid tracers).
Coat lower end of sleeve with a light coat of clean
motor oil and install sleeve. If seal ring is in place and
not pinched, very little hand pressure is required to
push sleeve completely in place.
Sleeve flange should extend 0.0031-0.0047 inch
(0.079-0.119 mm) above top surface of cylinder block.
If sleeve stand-out is excessive, check for foreign ma-
terial and under sleeve flange. If sleeve stand-out is
less than 0.0031 inch (0.079 mm), install shim under
sleeve flange as necessary. Shims are available in
thicknesses of 0.002, 0.004, 0.010, 0.020 and 0.031
inch
(0.05,
0.10, 0.25, 0.50 and 0.80 mm).
Pistons are fitted with two compression rings and
one oil ring. The top compression ring is a chrome
faced rectangular ring and upper side is marked TOP.
The second compression ring is a taper face ring
and is installed with largest outside diameter toward
bottom of piston. Upper side of ring is marked TOP.
The oil control ring can be installed either side up,
but make sure the coil spring expander is complete-
ly in its groove.
Additional piston ring information is as follows:
Ring End Gap:
Compression rings 0.014-0.022 in.
(0.035-0.056 mm)
Oil control ring 0.010-0.016 in.
(0.025-0.040 mm)
Ring Side Clearance:
Ibp compression ring 0.0035-0.0048 in.
(0.089-0.122 mm)
Second compression ring 0.0030-0.0042 in.
(0.076-0.107 mm)
Oil control ring 0.0014-0.0024 in.
(0.035-0.061 mm)
PiSTON PiNS
Aii Modeis
50.
The full floating type piston pins are retained
in the piston bosses by snap rings. Specifications are
as follows:
Piston pin diameter 1.4172-1.4174 in.
(35.997-36.002 mm)
Piston pin diametral
clearance in piston 0.0000-0.0001 in. tight
(0.0001-0.0025 mm tight)
Maximum allowable 0.0002 in. loose
(0.0051 mm loose)
Piston pin diametral
clearance in bushing 0.0005-0.0011 in.
(0.0127-0.0279 mm)
Maximum allowable 0.002 in.
(0.0508 mm)
Piston pin bushings are serviced semi-finished and
must be reamed or honed for correct pin fit after they
are pressed into connecting
rods.
Oversize piston pins
are not available.
CONNECTiNG RODS AND BEARiNGS
Aii Modeis
51.
Connecting rod bearings are of the slip-in, pre-
cision type, renewable from below after removing oil
pan, oil pump pressure and suction pipes, engine
balancer (if so equipped) and connecting rod caps.
When installing new bearing inserts, make certain
that projections on same engage slots in connecting
rod and cap. Also, make certain that cylinder iden-
tifying numbers on rod and cap are in register and
face toward camshaft side of engine. Numbers on rod
and cap should be stamped on same side as the flat
boss on small end of rod.
Connecting rod bearings are available in standard
size as well as undersizes of 0.010, 0.020 and 0.030
inch
(0.25,
0.51 and 0.76 mm).
Check crankshaft crankpins and connecting rod
bearings against the values which follow:
Crankpin diameter 2.5185-2.5193 in.
(63.97-63.99 mm)
Max. allowable out-of-round 0.0015 in.
(0.038 mm)
Max. allowable taper
per inch (25.4 mm) 0.0015 in.
(0.038 mm)
Rod bearing diametral clearance , . .0.002-0.004 in.
(0.051-0.102 mm)
Rod side clearance 0.006-0.012 in.
(0.152-0.305 mm)
Tighten connecting rod nuts to a torque of 18.5 ft.-
lbs.
(25
N-m),
then tighten nuts an additional 120 de-
grees (two flats on nut).
CRANKSHAFT AND MAiN BEARiNGS
Aii Modeis
52.
Crankshaft is supported in four main bearings
on D-155 and D-179 engines and five main bearings
on D-206, D-239 and D-268 engines. Main bearings
are of the nonadjustable, slip-in, precision type,
renewable from below after removing clutch and fly-
wheel for access to the two cap screws securing the
37
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