Connecting Rod: Service and Repair

PISTON AND CONNECTING ROD ASSEMBLY REMOVAL






1. Remove top ridge of cylinder bores with a reliable ridge reamer before removing pistons from cylinder block. Be sure to keep tops of pistons covered during this operation. Mark piston with matching cylinder number.






2. Remove oil pan. Scribe the cylinder number on the side of the rod and cap for identification.






3. Pistons have stamping in the front half of the piston facing towards the front of engine. The stamping is a weight identification for the assembly L is for light and H is for heavy. These assemblies should all be the same weight class. Service piston assemblies are marked with a S and can be used with either L or H production assemblies.
4. Pistons and connecting rods must be removed from top of cylinder block. Rotate crankshaft so that each connecting rod is centered in cylinder bore.
5. Remove connecting rod cap bolts. Push each piston and rod assembly out of cylinder bore. Be careful not to nick crankshaft journals.
6. After removal, install bearing cap on the mating rod.
7. Piston and Rods are serviced as an assembly.



INSTALLATION
1. Before installing pistons and connecting rod assemblies into the bore, be sure that compression ring gaps are staggered so that neither is in line with oil ring rail gap.







2. Before installing the ring compressor, make sure the oil ring expander ends are butted and the rail gaps.






3. Immerse the piston head and rings in clean engine oil, slide the ring compressor, over the piston. Be sure position of rings does not change during this operation.







4. The weight stamp designation L for light or H for heavy assembly will be in the front half of the piston facing toward the front of the engine.
5. Rotate crankshaft so that the connecting rod journal is on the center of the cylinder bore. Insert rod and piston assembly into cylinder bore and guide rod over the crankshaft journal.
6. Tap the piston down in cylinder bore, using a hammer handle. At the same time, guide connecting rod into position on connecting rod journal.
7. Install rod caps. Install cleaned and oiled rod bolts and tighten to 27 Nm (20 ft. lb.) Plus 1/4 turn.


CONNECTING RODS
1. See main bearing for measureing and specifiction procedures.

CAUTION: Do not rotate crankshaft or the Plastigage may be smeared. The rod bearing bolts should not be reused.

2. Before installing the NEW bolts the threads should be oiled with clean engine oil.
3. Install each bolt finger tight than alternately torque each bolt to assemble the cap properly.
4. Tighten the bolts to 27 Nm PLUS 1/4 turn (20 ft. lbs. PLUS 1/4 turn) Do not use a torque wrench for last step.






5. Using a feeler gauge, check connecting rod side clearance.