Cleaning and Inspection
Cylinder Block(1) Clean cylinder block thoroughly and check all core hole plugs for evidence of leaking.
(2) Examine block and cylinder bores for cracks or fractures.
Cylinder Bore
(1) The cylinder walls should be checked for out-of-round and taper with Tool. The cylinder bore out-of-round is 0.051 mm (0.002 inch) maximum and cylinder bore taper is 0.051 mm (0.002 inch) maximum.
If the cylinder walls are badly scuffed or scored, the cylinder block should be rebored and honed, and new pistons and rings fitted. Whatever type of boring equipment is used, boring and honing should be closely coordinated with the fitting of pistons and rings so that specified clearances may be maintained.
(2) Measure the cylinder bore at three levels in directions A and B. Top measurement should be 10 mm (0.39 inch) down and bottom measurement should be 10 mm (0.39 inch) up from bottom of bore.
Standard value: 87.5 mm (3.445 inch)
Pistons
(1) Piston and cylinder wall must be clean and dry. Piston diameter should be measured 90 degrees to piston pin at size location shown in the figure. Cylinder bores should be measured halfway down the cylinder bore and transverse to the engine crankshaft center line. Correct piston to bore clearance must be established in order to assure quiet and economical operation.
Standard value: 0.012 - 0.044 mm (0.0005 - 0.0017 inch)
(2) Pistons and cylinder bores should be measured at normal room temperature, 21°C. (70°F).
Piston Ring
(1) Wipe cylinder bore clean. Insert ring and push down with piston to ensure it is square in bore. The ring gap measurement must be made with the ring positioning at least 12 mm (0.47 inch) from bottom of cylinder bore. Check gap with feeler gauge.
Standard value:
Upper ring 0.23 - 0.52 mm (0.009 - 0.020 inch)
Intermediate ring 0.49 - 0.78 mm (0.019 - 0.031 inch)
Oil control ring 0.23 - 0.66 mm (0.009 - 0.026 inch)
Limit:
Upper ring 0.8 mm (0.031 inch)
Intermediate ring 1.0 mm (0.039 inch)
Oil control ring 1.0 mm (0.039 inch)
(2) Check piston ring to groove side clearance.
Standard value: 0.025 - 0.01i5 mm (0.0010 - 0.0026 inch)
Limit: 0.10 mm (0.004 inch)
Connecting Rod (Bearing Clearance)
(1) Place a piece of Plastic gauge across the entire width of the bearing shell in the bearing cap approximately 6.35 mm off center and away from the oil hole. In addition, suspect areas can be checked by placing Plastigage in the suspect area.
(2) Before assembling the rod cap with Plastigage in place, the crankshaft must be rotated until the connecting being checked starts moving toward the top of the engine.
Only the cap should be assembled and torqued to specifications. Do not rotate the crankshaft while assembling the cap or the Plastigage may be smeared, giving inaccurate results.
(3) Remove the bearing cap and compare the width of the flattened Plastigage with the metric scale provided on the package.
Standard value: 0.026 - 0.059 mm (0.0010 - 0.0023 inch)
Limit: 0.075 mm (0.0030 inch)
Connecting Rod Bearing Cap Bolt
(1) Since the connecting rod bearing cap bolts are torqued using a new procedure, they should be examined BEFORE reuse. If the threads are necked down, replace the bolts.
(2) Necking can be checked by holding a scale or straight edge against the threads. If all the threads do not contact the scale, the bolt should be replaced.