Removal and Replacement
PISTON & CONNECTING RODREMOVAL
1. Disconnect the battery cables.
2. Remove the cylinder head.
3. Remove the oil pan and suction tube.
4. Remove bolts and the block stiffener.
5. Using Miller Tool 7471-B crankshaft barring tool, rotate the crankshaft so all of the pistons are below TDC.
6. Before removing the piston(s) from the bore(s):
a. Remove any carbon ridge formations or deposits at the top of the bore with a dull scraper or soft wire brush.
b. If cylinder bore wear ridges are found, use a ridge reamer to cut the ridge from the bore. DO NOT remove more metal than necessary to remove the ridge.
7. Remove the Jet cooling nozzles, if equipped.
NOTE: If cylinders have ridges, the cylinders are oversize and will more than likely need boring.
8. Using a hammer and steel stamp, stamp the cylinder number in the top of each piston. The front of the piston is identified by a stamping on the top of the piston. DO NOT stamp in the outside 5 mm (0.197 in.) of the piston diameter. DO NOT stamp over the piston pin.
9. Mark the connecting rod and cap with the corresponding cylinder numbers.
10. Remove the connecting rod bolts and rod caps. Use care so the cylinder bores and connecting rods are not damaged.
11. Use a hammer handle or similar object to push the piston and connecting rod through the cylinder bore.
12. Store the piston/rod assemblies in a rack.
CLEANING
CAUTION: DO NOT use bead blast to clean the pistons. DO NOT clean the pistons and rods in an acid tank.
Piston
Clean the pistons and pins in a suitable solvent, rinse in hot water and blow dry with compressed air. Soaking the pistons over night will loosen most of the carbon build up. De-carbon the ring grooves with a broken piston ring and again clean the pistons in solvent. Rinse in hot water and blow dry with compressed air.
Connecting Rod
Clean the connecting rods in a suitable solvent, rinse in hot water and blow dry with compressed air.
INSPECTION
Piston
Inspect the pistons for damage and excessive wear. Check top of the piston, ring grooves, skirt and pin bore. Measure the piston skirt diameter (Fig. 90). If the piston is out of limits, replace the piston.
The upper groove only needs to be inspected for damage. Use a new piston ring to measure the clearance in the intermediate ring groove (Fig. 91). Minimum clearance is 0.045 mm (0.0018 in.), maximum clearance is 0.095 mm (0.0037 in.). If the clearance of the intermediate ring exceeds specifications, replace the piston.
Use a new oil ring to measure the clearance in the oil groove (Fig. 91). Minimum clearance is 0.040 mm (0.0016 in.), maximum clearance is 0.085 mm (0.0033 in.). If the clearance exceeds specifications, replace the piston.
Measure the pin bore (Fig. 92). The maximum diameter is 40.012 mm (1.5753 in.), Minimum is 40.006 mm (1.575 in.). If the bore is over limits, replace the piston.
Inspect the piston pin for nicks, gouges and excessive wear. Measure the pin diameter (Fig. 93). The minimum diameter is 39.990 mm (1.5744 in.), maximum 40.003 mm (1.5749 in.). If the diameter is out of limits, replace the pin.
Connecting Rod
Inspect the connecting rod for damage and wear. The I-Beam section of the connecting rod cannot have dents or other damage. Damage to this part can cause stress risers which will progress to breakage.
Measure the connecting rod pin bore (Fig. 94). The maximum diameter is 40.042 mm (1.5765 in.), minimum diameter is 40.019 mm (1.5756 in.). If out of limits, replace the connecting rod.
INSTALLATION
1. Lubricate the cylinder bores with clean engine oil.
2. Generously lubricate the rings and piston skirts with clean engine oil.
3. Compress the rings using a piston ring compressor tool (Fig. 95). If using a strap-type ring compressor, make sure the inside end of the strap does not hook on a ring gap and break the ring.
4. Bar the crankshaft so the rod journal for the piston to be installed is at BDC (Bottom Dead Center) - (Fig. 96).
5. Make sure the front of the piston is oriented properly according to the marking on the top of the piston and the numbers on the rod and cap are oriented as illustrated.
6. Position the piston and rod assembly into the cylinder bore with the front of the piston oriented properly according to the stamping in the top of the piston. In this position the numbers on the connecting rod should be facing the intake or camshaft side of the engine, and the rod bolt hex heads toward the oil cooler. Use care when you install the piston and connecting rod so the cylinder bore is not damaged. If a fractured split connecting rod is being installed, the long side of the connecting rod must be installed on the intake side of the engine.
7. Push the piston into the bore until the top of the piston is approximately 50 mm (2 in.) below the top of the block. Carefully pull the connecting rod onto the crankshaft journal.
8. Use clean engine oil to lubricate the threads and under the heads of the connecting rod bolts.
9. For machined connecting rods, the number stamped on the rod cap at the parting line must match and be installed towards the intake or camshaft side of the engine (Fig. 97). For fractured/split type connecting rods, the long end of the rod must be installed towards the intake side of the engine.
a. The connecting rod split/face must face toward the same side as the piston notch feature on the skirt. The split face will face toward the oil cooler side of the engine if properly installed.
10. Install the rod cap and bolts to the connecting rod. Tighten the connecting rod bolts evenly in 3 steps.
- Tighten the bolts to 30 Nm (22 ft. lbs.) torque.
- Tighten the bolts to 60 Nm (44 ft. lbs.) torque.
- Rotate 60° clockwise.
11. The crankshaft must rotate freely. Check for freedom of rotation as the caps are installed. If the crankshaft does not rotate freely, check the installation of the rod bearing and the bearing size.
12. Measure the side clearance between the connecting rod and the crankshaft (Fig. 98). DO NOT measure the clearance between the cap and crankshaft.
13. Install Jet piston cooling nozzles if equipped.
14. Install block stiffener. Torque to 43 Nm (32 ft. lbs.).
15. Install the suction tube and oil pan.
16. Install the cylinder head onto the engine.
17. Install a new filter and fill the crankcase with new engine oil.
18. Connect the battery negative cables and start engine.