Toyota 4-Runner 1985 Repair Manual page 86

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ENGINE MECHANICAL - Cylinder Block
EM-57
INSPECTION OF PISTON AND CONNECTING ROD
ASSEMBLY
1. CLEAN PISTON
(a) Scrape off carbon from the piston top.
(b) Using a groove cleaning tool or broken ring, clean the
ring grooves.
(c) Using solvent and a brush,clean the piston thoroughly.
CAUTION: Do not use a wire brush.
2. MEASURE PISTON DIAMETER
(a) Using a micrometer, measure the piston diameter as
shown.
Standard diameter: 91.960 - 91.990 mm
(3.6205 - 3.6216 in.)
(b) Check that the difference between the cylinder dia-
meter and the piston diameter is within specification.
If not within specification, replace the piston and/or rebore
the cylinder.
Piston clearance: 0.02 - 0.04 mm
(0.0008 - 0.0016 in.)
3. MEASURE CLEARANCE BETWEEN PISTON GROOVE
AND PISTON RING
Using a feeler gauge, measure the clearance between the
piston ring and the ring land.
If the clearance is greater than the maximum, replace the
piston.
Maximum clearance between compression ring No.1 or 2
and ring land: 0.2 mm (0.008 in.)
4. MEASURE RING END GAP
Measure the ring end gap.
(a) Insert the piston ring into the cylinder.
(b) Using a piston, push the ring to the bottom of the ring
travel.
(c) Using a feeler gauge, measure the end gap.
If not within specification, replace the ring. Do not file the
ring end.
Ring end gap:
Standard No.1
Maximum
No.2
Oil
No.1
No.2
Oil
0.24-0.39 mm (0.009-0.015 in.)
0.18-0.42 mm (0.007-0.017 in.)
0.20-0.82 mm (0.008-0.032 in.)
0.99 mm (0.039 in.)
1.02 mm (0.040 in.)
1.42 mm (0.056 in.)