Tools Required

J 8087 Cylinder Bore Gage

Important: Measurements of all components should be taken with the components at normal room temperature.

1. Inspect the engine block cylinder bore using the J 8087 .
2. Inspect the piston and pin. Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection .
3. Use the J 8087 and measure the cylinder bore diameter. Measure at a point 64 mm (2.5 in) from the top of the cylinder bore.



4. Measure the J 8087 with a micrometer and record the reading.



5. With a micrometer or caliper at a right angle to the piston, measure the piston 11 mm (0.433 in) from the bottom of the skirt.
6. Subtract the piston diameter from the cylinder bore diameter in order to determine piston-to-bore clearance. Refer to Engine Mechanical Specifications .
7. If the proper clearance cannot be obtained, select another piston and measure the clearances.
8. When the piston-to-cylinder bore clearance is within specifications, permanently mark the top of the piston for installation into the proper cylinder.

1. Clean the connecting rods in solvent.

Caution: Refer to Safety Glasses Caution in the Preface section.

2. Dry the connecting rods with compressed air.

1. Measure the piston pin to connecting rod bore using the following procedure:

1.1.	Using an outside micrometer, take two measurements of the piston pin in the area of the connecting rod contact.

1.2.	Using an inside micrometer, measure the connecting rod piston pin bore.

1.3.	Subtract the piston pin diameter from the piston pin bore.

1.4.	The clearance should not exceed 0.016 mm (0.0006 in).

2. If the clearance is excessive, replace the piston pin.

•	Inspect the pistons for the following conditions:

1. Using an outside micrometer, measure the width of the piston 46 mm (1.811 in) below the crown, top, of the piston at the thrust surface which is perpendicular to the centerline of the piston pin (1).
2. Compare the measurement to the diameter listed in the engine mechanical specifications.
3. You must replace the piston if any of its dimensions are out of specification. There are no oversized pistons available.

1. Piston pin bores and pins must be free of varnish or scuffing.
2. Use an outside micrometer to measure the piston pin in the piston contact areas.
3. Using an inside micrometer, measure the piston pin bore.
4. Subtract the measurement of the piston pin bore from the piston pin.
5. Compare the result with the engine mechanical specifications.
6. If the clearance is excessive, determine which piece is out of specification and replace as necessary.

1. Place the piston ring in the area of the bore where the piston ring will travel, approximately 25 mm (1 in) down from the deck surface. Be sure the ring is square with the cylinder bore by positioning the ring with the piston head.
2. Measure the end gap of the piston ring with feeler gages. Compare the measurements with those provided in the engine mechanical specifications.
3. If the clearance exceeds the provided specifications, the piston rings must be replaced.
4. Repeat this procedure for all the piston rings.

1. Roll the piston ring entirely around the piston ring groove. If any binding is caused by the ring groove, dress the groove with a fine file. If any binding is caused by a distorted piston ring, replace the ring.
2. With the piston ring on the piston, use feeler gages to check side clearance at multiple locations.
3. Compare your measurements with those found in the engine mechanical specifications.
4. If the clearance is greater than specifications, replace the piston rings.
5. If new piston rings do not bring the clearance within specification, the piston must be replaced.
6. When replacing the piston rings, only install re-ring sets that have a 1.2 mm (0.047 in) thick nitrided steel upper compression ring and multi-piece oil rings. The top compression ring may be installed with either side up. There is a locating dimple on the 2nd compression ring near the end for identification of the top side. Install the 2nd compression ring with the dimple facing up.