Piston, Connecting Rod, And Bearing Installation

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Fig 1: Piston, Connecting Rod, and Bearing

Courtesy of GENERAL MOTORS COMPANY

Callout	Component Name
Preliminary Procedure NOTE: Many internal engine components will develop specific wear patterns on their friction surfaces. Components MUST be separated, marked, or organized in a way to ensure installation to their original location and position. Take precautions in order to prevent interchanging of parts. Ensure all components are adequately marked with location, direction, or orientation when necessary.
1	Connecting Rod Bearing [4x] NOTE: The connecting rod bearing anti-rotation tab grooves are to point toward the right-hand side of the engine. Procedure Install NEW bearings to the connecting rods and lubricate each bearing with engine oil.
2	Piston and Connecting Rod Assembly [4x] NOTE: The connecting rods and caps must be installed in the same order and orientation in which they were removed. If new connecting rods are required, the connecting rod is provided as an assembly, and the upper rod will need to be disassembled from the lower cap. Procedure Install the EN-51454 guides into the connecting rod bolt holes. This protects the crankshaft journal during piston and connecting rod installation. NOTE: Ensure to stagger each piston ring end gap equally around the piston. NOTE: When installing a piston into a cylinder, use a ring compressor sleeve, such as EN-52490-74 or equivalent for best results. The following features should be looked for when selecting a ring compressor sleeve: Hard anodized and Teflon coated for low friction and prolonged wear resistance. Smooth radius that tapers down to the specific bore size. Sleeve should compress the piston rings smoothly and evenly. Using a ring compressor sleeve greatly reduces the difficulty with installing thin high-performance oil rings. If a ring compressor sleeve is unavailable, a universal ring compressor will work, but is more difficult to use. Install the EN-52490-74 ring compressor or equivalent on the piston. Ensure each piston ring end gap is spaced equally around the piston, refer to Piston and Connecting Rod Assemble . Lubricate the piston and the piston rings with engine oil. Do not disturb the piston ring end gap location. Lubricate the correct engine bore for the piston. NOTE: The piston must be installed oriented correctly to the front of the engine. Position the piston so that the arrow mark on the top of the piston points to the front of the engine. Install the ring compressor, the piston, and the connecting rod to the correct bore. Tap the piston into the bore with a hammer handle. Guide the connecting rod to the connecting rod journal while tapping the piston into place. Hold the ring compressor against the engine block until all the rings have entered the cylinder bore. Remove the connecting rod guides from the connecting rod bolt holes. Special Tools EN-51454 Connecting Rod Guides EN-52490-74 Piston Ring Compressor Equivalent regional tools: Special Tools .
3	Connecting Rod Bearing [4x] Procedure Install NEW bearings to the connecting rod caps and lubricate each bearing with engine oil.
4	Connecting Rod Cap [4x] Procedure Ensure that the connecting rod cap is properly oriented on the connecting rod.
5	Connecting Rod Bolt [8x] CAUTION: Refer to Fastener Caution . CAUTION: Refer to Torque-to-Yield Fastener Caution . Procedure Install NEW connecting rod bolts and tighten using the EN-45059 angle meter. Tighten the bolts a first pass to 25 N.m (18 lb ft). Tighten the bolts a final pass 75 degrees using EN-45059 angle meter. NOTE: Rotate the crankshaft to ensure that it moves freely and does not bind. Measure the connecting rod side clearance with a feeler gauge. Refer to Engine Mechanical Specifications . Measure the piston deck height. Refer to Engine Mechanical Specifications . Special Tools EN-45059 Angle Meter Equivalent regional tools: Special Tools .