Connecting Rod Bearing: Service and Repair
CONNECTING RODS AND BEARINGSFit all rods on one bank until complete.
The bearing caps are not interchangeable and should be marked at removal to insure correct assembly.
The bearing shells must be installed with the tangs inserted into the machined grooves in the rods and caps. Install cap with the tangs on the same side as the rod.
Limits of taper or out-of-round on any crankshaft journals should be held to 0.015 mm (0.0006 inch). Bearings are available in 0.025 mm (0.001 inch) and 0.254 mm (0.010 inch) undersize. Install the bearings in pairs. Do not use a new bearing half with an old bearing half. Do not file the rods or bearing caps.
CONNECTING ROD BEARING CLEARANCE
Connecting rod bearing clearance can be determined by use of Plastigage or equivalent. The following is the recommended procedure for the use of Plastigage.
1. Rotate the crankshaft until the connecting rod to checked is at the bottom of stroke.
2. Remove connecting rod cap and clean oil film from journal surface. Plastigage is soluble in oil.
3. Place a piece of Plastigage across the entire width of the bearing shell in the bearing cap approximately 6.35 mm (1/4 inch) off center and away from the oil hole (Fig. 56).
4. Assemble the connecting rod cap with the Plastigage in place.
NOTE: Do not rotate the crankshaft while assembling the cap. The Plastigage may become smeared, resulting in inaccurate results.
5. Tighten the connecting rod cap nuts to 54 Nm (40 ft. lbs.). Do not turn additional 1/4 turn until the final assembly.
6. Remove the bearing cap and Mopar the width of the flattened Plastigage with the scale on the Plastigage package (Fig. 57). Locate the band closest to the same width. This band indicates the amount of oil clearance. Differences in readings on the ends indicate the amount of taper present. Record all readings taken.
CONNECTING ROD BOLTS
1. Inspect connecting rod bolts for necking (stretching).
NOTE: The connecting rod cap bolts should be examined before reuse. If the threads are necked down the bolts should be replaced (Fig. 58).
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.
3. Before installing the nuts the threads should be oiled with engine oil.
4. Install nuts on each bolt finger tight then alternately torque each nut to assemble the cap properly.
5. Tighten the connecting rod cap nuts to the specified torque.
CONNECTING ROD SIDE CLEARANCE
1. Mount a dial indicator to a stationary point on the engine. Locate probe perpendicular to and contacting the connecting rod cap. Move connecting rod all the way to rear of its travel. Zero the dial indicator. Move connecting rod forward to limit of travel and read the dial indicator (Fig. 59). Record reading. Repeat procedure for each connecting rod. Turn crankshaft for connecting rod accessibility.