Page 153 of 1139

1.
Block and Piston Inspection
Remove the crankshaft and pistons (se e pageT -121.
Check the piston for distortion or cracks,
Measure the piston diameter at a point I1 mm {0.4in.) from the bottom of the skirt. There are two
standard-size pistons (No Letter or A, and B). The
letter is stamped on the top of the piston. Letters
are also stamped on the block as cylinder bore
stzes.
Piston Diameter:
Standard (Newl:
No Letter {or A): 85.980 85.990 mm(3.3850 3.3854 in.)
B: 85.970-85.980 mm(3.3846-3.3850 in.)
Service Limit:
No Lefter lor A): 85.930 mm (3.3831 in.)
B: 85.920 mm 13.3827 in.)
Oversize Piston Diameter:
0.25: 86.230-85.240 mm (3.3949 -3.3953 in.l
4. Measure wear and taper in direction X and Y at
three levels in each cylinder as shown. lf
measurements in any cylinder are beyond the
oversize bore service limit. replace the block. lf the
block is to be rebored, refer to step 7 after reboring.
Cylinder Bore Size
Standard (New):
A or l: 86.010 86.020 mm
13.3862 3.3866 in.)
B or ll: 86.000 86.010 mm(3.3858 3.3862 in.)
Service Limit: 86.070 mm (3.3886 in.)
Oversize:
O.25t 96.250 86.260 mm (3.3957 3.3961 in.)
Reboring limit: 0.25 mm (0.01 in.l max.
Bore Taper:
Limit: (Difference between first and third
measurement) 0.05 mm (0.002 in.)
FirstMeasurement
SecondMeasutement
ThirdMeasurement
(cont'd)
7-15
6 mm {0.2 in.}
6 mm {0.2 in.}
Page 154 of 1139
Engine Block
Block and Piston Inspection (cont'd)
Scored or scratched cylinder bores must be honed.
Check the top of the block for warpage. Measure
along the edges and across the center as shown.
Engine Block Warpage
Standard lNew): 0.07 mm (0.003 in.) max.
Service Limit: 0.10 mm (0.004 in.l
PRECISION STRAIGHT EDGE
7-16
\
7. Calculate the difference between the cylinder bore
diameter and the plston diameter. lf the clearance
is near or exceeds the service limit, inspect thepiston and cvlinder block for excessive wear.
Piston-to-Cylinder Clearance
Standard lNew): 0.020 0.040 mm
{0.0008 0.0016 in.)
Service Limit: 0.05 mm (0.002 in.l
++ PISTON-TO-CYLINDERCLEARANCE
\
(
Page 155 of 1139
Cylinder Honing
Only a scored or scratched cylinder bore should be
noneo.
Measure the cylinder bores {see page 7-15).
lf the block is to be reused, hone the cylinders and
remeasure the bores.
Hone the cylinder bores with honing oil and a fine(400 grit) stone in a 60 degree cross-hatch pattern
(A). Use only a rigid hone with 400 grit or finer
stone such as Sunnen, Ammco, or equivalent. Do
not use stones that are worn or broken.
When honing is complete, thoroughly clean the
engine block of all metal particles. Wash the
cylinder bores with hot soapy water, then dry and
oil them immediately to prevent rusting. Never use
solvent, it will only redistribute the grit on the
cylinder walls.
lf scoring or scratches are still present in the
cylinder bores after honing to the service limit,
rebore the cylinder block. Some light vertical
scoring and scratching is acceptable if it is not deep
enough to catch your fingernail and does not run
the full length of the bore.
'L
3.
7-17
Page 156 of 1139
Engine Block
Piston, Pin, and Connecting Rod Replacement
Disassembly
1. Remove the piston from the cylinder block (see
page 7 -12).
2. Apply engine oilto the piston pin snap rings (A),
and turn them in the ring grooves until the end
gaps are lined up with the cutouts in the piston pin
bores (B).
NOTE; Take care not to damage the ring grooves.
Remove both snap rings (A). Start at the cutout in
the piston pin bore. Remove the snap rings
carefully so they do not go flying or get lost. Wear
eve protection.
7-18
\"
4.Heat the piston and connecting rod assembly to
about 158'F (70"C), then remove the piston pin.
(\
Page 157 of 1139
v
Inspection
NOTE: Inspect the piston, piston pin, and connecting
rod when they are at room temperature.
1. Measure the diameter of the piston pin.
Piston Pin Diameter
Standard (New): 21.961 21.965 mm(0.8646-0.8648 in.)
Service Limit: 21.953 mm 10.8643 in.l
2. Zerc the dial indicator to the piston pin diameter.
3. Check the difference between the Diston Din
diameter and piston pin hole diameter in the piston.
Piston Pin-to-Piston Clearance
Standard (Newl: -0.005 to +0.002 mm(-0.00020 to +0.00008 in.)
Service Limit: 0.005 mm (0.0002 in.)
Measure the piston pin-to-connecting rod clearance.
Piston Pin.to-Connecting Rod Clearance
Standard (New): 0.005 0.015 mm
{0.0002 0.0006 in.}
Service Limil: 0.02 mm (0.0008 in.l
4.
(cont'd)
7-19
Page 158 of 1139
Engine Block
Piston, Pin, and Connecting Rod Replacement (cont'd)
Reassembly
1. Install a piston pin snap ring (A).
Coat the piston pin bore in the piston, the bore in
the connecting rod, and the piston pin with engine
oil.
Heat the piston to about 158"F (70'C).3.
7 -20
\
4. Install the piston pin (A). Assemble the piston (B)
and connecting rod (C) with the arrow (D) and the
embossed mark (E) on the same side. -
Install the remaining snap ring (F).
Turn the snap rings in the ring grooves untilthe
end gaps are positioned at the bottom of the piston.
(
5.
6.
I
Page 159 of 1139

Piston Ring Replacement
1. Remove the piston {rom the cylinder block (see
page 7 -121.
2. Using a ring expander (A), remove the old piston
rings (B).
3. Clean all ring grooves thoroughly with a squared-
off broken ring or ring groove cleaner with a blade
to fit the pislon grooves. The top and 2nd ringgrooves are 1.2 mm (0.05 in,)wide. The oil ringgroove is 2.0 mm (0.08 in.) wide. File down a blade
lf necessary. Do not use a wire brush to clean the
ring grooves, or cut the ring grooves deeper with
the cleaning tools.
NOTE: lf the piston is to be separated from the
connecting rod, do not install new rings yet.
4. Using a piston, push a new ring (A) into the
cylinder bore 15-20 mm {0.6-0.8 in.) from the
bottom.
15 20 mm (0.6 0.8 in.)
I
Measure the piston ring end-gap (B) with a feelerga uge:
. lf the gap istoo small, checkto see if you have
the proper rings for your engine.. lf the gap istoo large, recheckthecylinder bore
diameter against the wear limits (see slep 4 onpage 7-15).. lf the bore is overthe service limit, the cylinder
block must be rebored.
Piston Ring End-Gap
Top Fing
Standard (Newl: 0.20 0.35 mm(0.008 0.014 in.l
Service Limit: 0.60 mm (0.024 in..
Second Ring
Standard (New): 0.40-0.55 mm
{0.016 0.022 in.)
Service Limit: 0.70 mm (0.028 in.)
Oil Ring
REKEN manufactured ring
Standard (Newl: 0.25 0.65 mm(0.010 0.026 in.l
Service Limit: 0.75 mm (0.030 in.)
FEDERAL MOGUL manufactured rino
Standard lNew): 0.20 0.70 mm
{0.008 0.028 in.}
Service Limit: 0.80 mm (0.031 in.)
B
(cont'd)
7-21
Page 160 of 1139

Engine Block
Piston Ring Replacement (cont'd)
6. Install the top ring and second ring as shown.The
top ring (A) has a 1R mark or no mark and the
second ring (B) has a 2R mark or 2ND mark. The
marks must be facing upward.
o\,"16.
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P'ffi+a\aq*-pogd
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V
Piston Ring oimensions:
t ToP Ring {Standardl:| | o A: 3.1 mm {0.12 in.l
| | J - B:1.2 mm {0.05 in.)Socond Ring {Standard):A:3.4 mm {0.13 in.}- A- B:'1.2 mm (0.05 in.i
7, Rotate the rings in their grooves to make sure they
do not bind.
7-22
\{
8. Position the ring end gaps as shown:
OIL RING GAPAbout 90'SECOND RING GAP
About 45"
OIL RING GAPTOP RING GAPand SPACERRING GAPPISTON PIN
9. After installing a new set of rings, measure the
ring-to-groove clearances:
Top Ring Clearance
Standard {New}:
0.035-0.060 mm {0.0014-0.0024 in.)
Service Limit: 0.13 mm (0.005 in.)
Second Ring Clearance
Standard lNew):
REKEN manutactured ring
0.030-0.055 mm (0.0012-0.0022 in.)
FEDERAL MOGUL manulactured ring
0.025-0.060 mm (0.001 0-0.0024 in.)
Service Limit: 0.13 mm (0.005 in.)
{