GM 10103688 Piston Assembly, W/ Pinion

Prior to removing the piston/connecting rod assemblies, remove the cylinder head(s), the oil pan and the oil pump. Use your fingernail to feel if a ridge has formed at the upper limit of ring travel (about 1/4-inch down from the top of each cylinder). If carbon deposits or cylinder wear have produced ridges, they must be completely removed with a special tool. Follow the manufacturer's instructions provided with the tool. Failure to remove the ridges before attempting to remove the piston/connecting rod assemblies may result in piston breakage. After removing all of these ridges from these cylinders, turn an engine upside down so that its crankshaft faces up. Prior to removing connecting rods, see whether there is any endplay using feeler gauges. Insert feeler gauges between number one connecting rod and crankshaft throw until play is eliminated. Endplays are equal to thickness(es) of feeler gauge(s). When the service limit is over exceeded, new connecting rods need to be ordered accordingly. In case you install new rods (or a new crankshaft), endplay might fall below this minimum. Always check for marks on both caps and connecting rods-they should be there. If there aren't any marks on them, use a small center punch and put an appropriate number of indentations into each rod and cap (1, 2, 3 etc.) depending on what type of engine one is dealing with and which cylinder it relates to Loosen each of these connecting rod cap nuts 1/2 turn at a time until they can hand-removed. Take off bearing insert from number one connect rod cap. Do not let bearing insert accidentally fall out of cap Slip short piece of rubber hose or plastic tubing over each bolt in connecting rod cap while removing pistons so that scratches or grooves cannot damage any crankshaft journal or cylinder wall Push assembly out through top of engine and remove bearing insert. On piston pin hole side, use a wooden or plastic hammer handle to push on upper bearing surface in connecting rod. If you feel any resistance simply double check that the ridge was completely removed from the cylinder. Repeat this process for all remaining cylinders After removal, install connecting rod caps and bearing inserts back into their respective connecting rods and tighten cap nuts finger tight. Until reassembly, consider leaving old bearing inserts in place to prevent the accidental nicking or gouging of the connecting rod bearing surfaces Don't take pistons apart from connecting rods.

Before inspecting the piston/connecting rod assemblies, you should clean them, and it's important to remove the original piston rings. This is crucial because new rings should always be used when reassembling the engine.

After removing the cap and original bearing inserts, wipe the connecting rod and cap bearing surfaces meticulously with a clean, lint-free cloth to maintain impeccable cleanliness.

Install the bottom oil ring spacer and its components, ensuring they are free in the groove, and repeat the process for all piston assemblies.

The connecting rod bearings should be lubricated and then installed into their appropriate rod and rod cap.

The rods must be checked for twist and bending, and inspected for nicks or cracks. Any issues found will necessitate the replacement of the rod.

If a piston ring expanding tool is available, use it to remove each of the rings from the piston. Alternatively, expand the ring just enough to clear the lands of the piston body, then place strips of tin (about Three-quarters in. wide) under the ring at equal distances around the piston and use a slight twisting motion to 'walk' the ring up and off the top.