Oldsmobile 10100061 Piston & Pinion Asm(.04Mm Oversize)

First, before beginning the inspection, clean the piston/connecting rod assemblies and remove the old piston rings so that you always use new ones when reassembling the engine. Use a piston ring installation tool to take off the rings without damaging the pistons. Once most of the deposits have been scraped away, scrape every bit off carbon deposits from the piston tops by using a hand-held wire brush or fine emery cloth; do not use a wire brush driven by a drill motor to prevent erosion of the pistons. A tool for cleaning out carbon from a ring groove or an old ring piece should be used to sweep out carbon from ring grooves without scoring their sides. When deposit removal is complete, clean these with solvent and dry with compressed air if available. If neither heavy wear nor damage is found on pistons and cylinder walls, and also no reboring of engine block has occurred then new pistons may not be necessary. Even vertical wear on piston thrust surfaces and slight top ring looseness in its groove are classic symptoms of normal piston wear. If one intends to rebuild an engine, then it's necessary to use new rings for each piston. Every single piston must be thoroughly inspected for cracks at skirt, pin bosses as well as ring lands. Inability to move freely due to scoring or scuffing; burnt areas around crown edge; holes in its crown will mean problems such as overheating abnormal combustion including spark knock needs immediate attention. The presence of small pits indicates that there is coolant leakage which must be rectified. Measure this with feeler gauge next to a new piston ring in each groove at many points. Bore measurements are taken at specific points depending on engine type while diameter checks are made across several positions along side clearance of each groove with reference to feeler gauge readings and specifications provided by vehicle maker require usage of various locations according kind machine used During measurement of heights-which are taken at different locations with respect to ring manufacturers' specifications-these must never go beyond the given limit. However, if the clearances are greater than specified, then it means that the block must be rebored and new pistons and rings installed. If there is any play in a piston-to-rod clearance, this can be checked by taking the assembly to an automotive machine shop where excessive wear can be addressed. In case piston disassembling is required, consult an automotive machine shop but when there, do not take apart pistons as well as connecting rods unless unnecessary and at that stage examine connecting rods for bend and twist too. Look out for cracks or damage in connecting rods doing temporary removal of rod caps to inspect or replace worn bearing inserts before cleaning both rod and cap bearing surfaces so that when connecting rod knock may necessitate a complete rebuild of this engine that is already being done.

Clean any Plastigage residue from the rod journal and bearing face, apply a uniform layer of moly-base grease or engine assembly lube, and reinstall the connecting rod and cap, tightening the nuts to the specified torque.

After installation, rotate the crankshaft manually to check for binding, and verify connecting rod endplay as needed.

If the endplay exceeds the service limit, new connecting rods will be required.

Repeat the procedures for the remaining seven cylinders, turning the crankshaft as necessary to access the connecting rod nuts, and reuse the rubber or plastic tubing for each assembly.

A piston ring compressor is used around the piston, ensuring the base of the compressor is flush with the cylinder block.

The piston must be attached to its appropriate connecting rod, a task best performed by a professional with the necessary supports and an arbor press.

Check piston-to-rod clearance by twisting the piston and rod in opposite directions. Noticeable play indicates excessive wear that requires correction.

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.

Loosen the connecting rod cap nuts gradually until they can be removed by hand.