Piston and Connecting Rod

PISTON AND CONNECTING ROD DISASSEMBLY
1. CHECK FIT BETWEEN PISTON AND PISTON PIN
Try to move the piston back and forth on the piston Pin.
If any movement is felt, replace the piston and pin as a set.

2. REMOVE PISTON RINGS
(a) Using a piston ring expander, remove the 2 compression rings.
(b) Remove the 2 side rails and oil ring by hand.

HINT: Arrange the piston rings in the correct order only.

3. DISCONNECT CONNECTING ROD FROM PISTON
(a) Using a small screwdriver, pry out the 2 snap rings.
(b) Gradually heat the piston to approx. 60°C (140 F).

(c) Using a plastic-faced hammer and brass bar, lightly
tap out the piston pin and remove the connecting rod.

HINT:
- The piston and pin are a matched set.
- Arrange the pistons, pins, rings, connecting rods and bearings in the correct order.

PISTON AND CONNECTING ROD INSPECTION
1. CLEAN PISTON
(a) Using a gasket scraper. remove the carbon from the piston top.

(b) Using a groove cleaning tool or broken ring, clean the piston ring grooves.

2. INSPECT PISTON
A. Inspect piston oil clearance
(a) Using a micrometer, measure the piston diameter at right angles to the piston pin center line, 23.2 mm (0.913 in.) from the piston head.
Piston diameter: 87.406 - 87.416 mm (3.4412 - 3.4416 in.)
(b) Measure the cylinder bore diameter in the thrust directions.
(See step 4 in cylinder block inspection and repair)
(c) Subtract the piston diameter measurement from the cylinder bore diameter measurement.
Standard oil clearence: 0.084 - 0.106 mm (0.0033 - 0.0042 in.
Maximum oil clearance: 0.13 mm (0.0051 in.)
If the oil clearance is greater than maximum. replace all the 6 pistons. If necessary. replace the cylinder block.

HINT: The shape of the piston varies for the RH and LH banks. The RH piston is marked with "R" the LH piston with "L".

B. Inspect piston ring groove clearance Using a feeler gauge. measure the clearance between new piston right and the wall of the ring groove. Ring groove clearance:
No.1 0.020 - 0.070 mm (0.0008 - 0.0028 in.)
No.2 0.020 - 0.060 mm (0.0008 - 0.0024 in.)
If the clearence is not as specified, replace the piston.

C. Inspect piston ring end gap
(a) Insert the piston ring into the cylinder bore.
(b) Using a piston. push the piston ring a little beyond the bottom of the ring travel, 105 mm (4.13 in.) from the top of the cylinder block.
(c) Using a feeler gauge. measure the end gap.

Standard end gap:
No.1 0.25 - 0.35 mm (0.0098 - 0.0138 in.)
No.2 0.35-0.45 mm (0.0138 - 0.0177 in.)
Oil (Side rail) 0.15 - 0.40 mm (0.0059 - 0.0157 in.)
Maximum end gap:
No.1 0.95 mm (0.0374 in.)
No.2 1.05 mm (0.0413 in.)
Oil (Side rail) 1.00 mm (0.0394 in.)
If the end gap is greater than maximum. replace the piston ring. If the end gap is greater than maximum, even with a new piston ring, replace the cylinder block.

D. Inspect piston pin fit
At 60°C (140°F), you should be able to push the piston pin into the piston pin hole with your thumb.

3. INSPECT CONNECTING ROD
A. Inspect connecting rod alignment
Using a rod aligner and feeler gauge, check the connecting rod alignment

Check for bend.
Maximum bend: 0.05 mm (0.0020 in.) per 100 mm (3.94 in.)
If bend is greater than maximum, replace the connecting rod assembly.
Check for twist.
Maximum twist: 0.15 mm (0.0059 in.) per 100 mm (3.94 in.)
If twist is greater than maximum, replace the connecting rod assembly.

B. Inspect piston pin oil clearance
(a) Using a caliper gauge, measure the inside diameter of the connecting rod bushing.
Bushing inside diameter: 22.005 - 22.014 mm (0.8663 - 0.8667 in.)

(b) Using a micrometer, measure the piston pin diameter.
Piston pin diameter: 21.997 - 22.006 mm (0.8660 - 0.8664 in.)
(c) Subtract the piston pin diameter measurement from the bushing inside diameter measurement.
Standard oil clearance: 0.005 - 0.011 mm (0.0002 - 0.0004 in.)
Maximum oil clearance: 0.05 mm (0.0020 in.)
If the oil clearance is greater than maximum, replace the bushing. If necessary, replace the piston and piston pin as a set.

C. If necessary, replace connecting rod bushing
(a) Using SST and a press, press out the bushing. SST 09222-30010

(b) Align the oil holes of a new bushing and the connecting rod.
(c) Using SST and a press, press in the bushing. SST 09222-30010

(d) Using a pin hole grinder, hone the bushing to obtain the standard specified clearance (see step B above) between the bushing and piston pin.

(e) Check the piston pin fit at normal room temperature. Coat the piston pin with engine oil, and push it into the connecting rod with your thumb.

D. Inspect connecting rod bolts
Using vernier calipers. measure the tension portion diameter of the bolt.
Standard diameter: 7.2 - 7.3 mm (0.284 - 0.287 in.)
Minimum diameter: 7.0 mm (0.276 in.)
If the diameter is less than minimum, replace the bolt.