Piston diameter should be measured 1.73" (44 mm) from top of piston.
Note. DO NOT machine oversize pistons, or engine balance will be affected.
Scheme 18
Scheme 19
- Main bearing caps are a press fit. All main caps incorporate side bolts except the rear. Remove side bolts. Remove main cap bolts. Using Slide Hammer (J-6125-B) and Main Bearing Cap Puller (J-41348), carefully remove caps for service.
- Install the upper crankshaft main bearings.
- Install the crankshaft. Lubricate the crankshaft to crankshaft main bearing contact areas with engine oil or engine assembly lubricant. NOTE: In order to prevent the possibility of cylinder block or crankshaft bearing cap damage, the crankshaft bearing caps are tapped into the cylinder block cavity using a brass, lead, or a leather mallet before the attaching bolts are installed. Do not use attaching bolts to pull the crankshaft bearing caps into the seats. Failure to use this process may damage a cylinder block or a bearing cap.
- Install the lower crankshaft main bearings into the main bearing caps.
- Install the crankshaft main bearing cap bolts. Start the crankshaft main bearing cap bolts by hand. Ensure the bottom of the crankshaft main bearing cap is parallel to the bottom of the channel. Tighten Tighten the crankshaft main bearing cap bolts in equal increments. Do not completely tighten one bolt at a time to prevent the cap from being cocked. Tighten the bolts to 70 N.m (52 lb ft) to fully seat the crankshaft main bearing caps. Loosen the bolts 360 degrees counterclockwise. Tighten the bolts to 20 N.m (15 lb ft), then 40 N.m (30 lb ft). Use J 36660-A to tighten the bolts in steps: 35 degrees + 35 degrees + 40 degrees for a total of 110 degrees.
- Install the side main bolts. Apply GM P/N United States 12345493, GM P/N Canada 10953488 or the equivalent to the side main bolts. Tighten Tighten the side crankshaft main bearing cap bolts to 15 N.m (11 lb ft). Use J 36660-A to tighten the bolts an additional 45 degrees.