GM 12631195
Piston

Handling the Piston replacement alongside connecting rod and bearing requires the withdrawal of both Oil Pan and Cylinder Head. The j 24270 must remove the ring ridge while the Piston stays at its bottom position wrapped in cloth. After moving the Crankshaft to position the Piston at the top stroke you must remove the cloth debris and note the connecting rods and caps for correct assembly. The technician extracts the connecting rod and Piston from the engine block by using the j-43966-1 after discarding the bolts and nuts and removing the connecting rod nuts and cap. Hot water mixed with detergent should clean the cylinder holes followed by engine oil application and a dry clean cloth to wipe them down. Before assembly place engine oil on the Piston as well as the Piston rings and cylinder bore and bearing surfaces. Finalize the assembly by using the j-43966-1 to place the Piston into its original bore while gently tapping the upper area with a wooden hammer handle. First position the stamped mark on the Piston to face the engine front while using the j 8037 to apply pressure on the engine block for complete Piston Ring cylinder entry. Then install connecting rod caps onto their respective rods with previously marked number alignment. New connecting rod bolts require installation followed by equal bolt torque of 25 nm (18 lb ft) on the first stage while the j 45059 tool adds 100 degrees of additional torque for the final stage. The side clearance measurement of the connecting rod should be done using a feeler gauge and must fall between 0.070-0.370 millimeters (0.0027-0.0145 inches). To complete the procedure you should put both the Cylinder Head and Oil Pan in position.

Clean the cylinder bores with hot water and detergent or light honing, then swab them with engine oil and a clean, dry cloth.