Piston, Connecting Rod, and Bearing Installation
^ Tools Required^ J 29789 Piston Ring Compressor
^ J 39946 Crankshaft Rotation Socket
^ J 36660 Torque/Angle Meter
PISTON AND CONNECTING ROD ASSEMBLY PROCEDURE
1. Liberally lubricate the cylinder walls, piston rings and piston skirts with engine oil.
2. Select the correctly numbered piston/connecting rod assembly for the cylinder. An arrow (9) showing proper piston orientation is located on the top of the piston.
3. Coat the crankshaft bearing journal and installed connecting rod bearings with GM crankshaft prelube GM P/N 1052367.
IMPORTANT: If the connecting rod bearings have been used in a running engine, you must replace them with NEW connecting rod bearings for reassembly.
4. Compress the piston rings using the J 29789 or equivalent.
5. Using both hands, slowly guide the piston and connecting rod assembly into the cylinder from the top and bottom of the cylinder. DO NOT allow the connecting rod to contact the cylinder wall.
IMPORTANT: Extreme care must be exercised when installing the piston and connecting rod in order to be sure the rod does not scrape or nick the cylinder bore or the crankshaft surfaces.
6. When the piston ring compressor contacts the deck surface, gently tap the piston into the cylinder using the handle end of a dead-blow hammer. Guide the connecting rod onto the crankshaft bearing journal while tapping the piston into the cylinder.
CONNECTING ROD BEARING CLEARANCE MEASUREMENT PROCEDURE
1. Before final assembly it is important check the clearance of the new connecting rod bearings. Remember, connecting rod bearings that have been run in an engine should NEVER be reused.
2. Place a length of fresh, room temperature plastic gaging material all the way across all the connecting rod bearing journal.
3. Install the connecting rod end cap on its original connecting rod making sure the bearing lock tangs are aligned on the same side of the rod. When properly installed, the connecting rod bearing cap notches should be paired, as shown, on the crankpin.
4. Lubricate new connecting rod bolts with engine oil and install in the connecting rod.
^ Tighten the connecting rod bolts to 30 Nm (22 ft. lbs.).
IMPORTANT: DO NOT reuse the old connecting rod bolts.
NOTICE: Refer to Fastener Notice in Service Precautions.
5. Loosen the connecting rod bolts until the torque reading is zero.
6. Re-tighten the connecting rod bolts.
6.1 First Pass
Tighten the connecting rod bolts to 25 Nm (18 ft. lbs.).
6.2 Final Pass
Tighten the connecting rod bolts an additional 110° using the J 36660.
7. Allow the assembly to sit for at least two minutes.
8. Remove the connecting rod cap bolts.
9. Remove the connecting rod cap.
10. Determine the connecting rod bearing clearance by comparing the width of the flattened plastic gaging material at its widest point with the graduation on the gaging material container.
11. Compare your measurements with the engine mechanical specifications. If the new bearings do not provide the proper crankshaft to bearing clearance, re-measure the crankshaft journals for the correct specified size and check to make sure you have the correct new bearings. If the crankshaft journals are incorrectly sized, replace the crankshaft. No crankshaft machining is permitted and undersized bearings are not available.
12. Clean the plastic gauging material from the connecting rod bearing journals using a soft lint-free cloth.
CONNECTING ROD FINAL ASSEMBLY PROCEDURE
1. Install the connecting rod end cap on its original connecting rod making sure the bearing lock tangs are aligned on the same side of the rod. When properly installed, the connecting rod bearing cap notches should be paired, as shown, on the crankpin.
2. Lubricate the connecting rod bolts with engine oil and install in the connecting rod.
Tighten the connecting rod bolts to 30 Nm (22 ft. lbs.).
NOTICE: Refer to Fastener Notice in Service Precautions.
3. Loosen the connecting rod bolts until the torque reading is zero.
4. Re-tighten the connecting rod bolts.
4.1 First Pass
Tighten the connecting rod bolts to 25 Nm (18 ft. lbs.).
4.2 Final Pass
Tighten the connecting rod bolts an additional 110° using the J 36660.
5. During and after installation, check to make sure each piston is positioned properly in the correct cylinder. The locating arrow on the top each piston (9) must be pointing toward the front of the engine.
6. Repeat these procedures for the remaining piston/connecting rod assemblies using the J 39946 in order to rotate the crankshaft.