GM 12539085
Pistons

The replacement of piston and connecting rod and bearing requires detachment of the negative Battery Cable as the first step. You need to detach the Cylinder Head together with the oil level sensor along with the Oil Pan and the oil pump pipe and screen. The presence of a pronounced ridge at the top of piston travel requires the cylinder ridge reamer (J24270) before continuing since forceful action can potentially harm piston rings or piston. Affix marks to the connecting rod cap and rod before removing the connecting rod bolts and cap. Connect the connecting rod guide (J41507) to the connecting rod assembly while tightening it by hand. Press the connecting rod assembly with the connecting rod guide (J41507) toward the top of the cylinder while pushing with hand pressure and then remove both the piston and connecting rod assembly and the connecting rod guide (J41507). A Piston Ring expander should be used for ring installation while creating proper compression by staggering the gaps between rings. Apply oil onto the cylinder at bottom dead center position and mount the connecting rod bearing into position. The Piston Ring compressor (J8037) should be used to mount the piston and connecting rod assembly with its ridges pointing towards the engine front. The technician should securely lift and support the vehicle while using the connecting rod guide (J41507) to guide the connecting rod through the cylinder before removing it. Insert the connecting rod cap onto its spot before torquing the connecting rod cap bolts to 27 nm (20 ft.lb.) while employing the torque angle meter (J36660-A) for an extra 50 degrees of rotation. To complete the procedure install the oil pump pipe and screen assembly and the Oil Pan and also mount the oil level sensor and Cylinder Head before reconnecting the negative Battery Cable.

The additional materials for Piston maintenance appear in the engine repair section. Internal engine components without specified separate service procedures indicate that the manufacturer did not author such procedures. Unit repair typically encompasses service procedures, machining, cleaning, inspection, and fitting necessary for engine overhaul, including cylinder boring and honing, connecting rod and bearings - fitting, crankshaft and bearings - fitting, camshaft bearings - replacement, connecting rod and Piston - disassembly, cylinder head - disassembly, valve train components (Valves, Seats, Springs, Rockers, etc.), Oil Pump - disassembly, pistons and rings - fitting, thread repair information, and valve and seat grinding (Valve Job). The service covers timing components (.Chain, Belt, Gears) together with other components.