GM 22527479 Piston & Pinion (Std) LH(3.7993 To 3.8003In)

Before removing the pistons, inspect the cylinder bore for a ridge felt by hand. Use a ridge reamer for that purpose. To start piston removal, you need to match each connecting rod cap with its respective rod number. Place a rubber hose over the connecting rod studs on the crankshaft and cylinders so they don't get scratched or damaged. Then, lubricate the cylinder wall with clean engine oil and tap the piston gently out using a wooden dowel. Repeat for all pistons in the same way. After taking them off, clean cylinder bore and pistons thoroughly using soap and water before applying clean engine oil to prevent corrosion. The piston rings are removed using ring expander tool then piston grooves are cleaned. Cylinder bore diameter and piston clearance are measured by telescopic gauge in combination with micrometer. Piston should be marked for reference. Pistons having pressed-in wrist pins must be removed using special tools while snap-ringed pins can be taken out through use of screwdriver. Replace / install wrist pins as required. When you fit in new rings, make sure they do not get damaged by utilizing piston ring expander. According to manufacturer's instructions, place the rings correctly on the pistons just as directed by their manufacturers' manual guides . In case of any damage or wear-out, inspect and replace connecting rod bearings when necessary. Use Plastigage® to check bearing clearance. Choose appropriate undersized bearing shell where necessary if there's an excessive clearance . Observe proper side clearance between rods and crankshaft in installing bearings, pistons, and connecting rods as per manufacturer specifications . Finally, reassemble engine components including oil pump(s), oil pan(s), cylinder head(s) and intake manifold(s).

In most cases of high mileage engines, original pistons need replacement due to the requirement of boring the cylinders to a larger size for normal wear compensation; however, if the cylinder walls only need slight finish honing, old pistons may be reused if they are in good condition. Begin by washing the connecting rods and pistons in a cleaning solvent and drying them with compressed air if available, avoiding wire brushes or abrasive tools on any piston part. Clean the ring grooves with a groove cleaner tool, ensuring the oil ring holes and slots are also clean. Check the rods for twist, bending, nicks, or cracks, replacing any damaged rods. Inspect the piston for cracked ring lands, skirts, or pin bosses, as well as worn or wavy ring lands, scuffed skirts, and eroded areas at the top; any damaged pistons or those showing excessive wear should be replaced. Look for nicks in the ring grooves that may cause the rings to hang up. While the piston is still connected to the connecting rod, swivel the rod back and forth to assess the degree of difficulty, comparing all piston/rod assemblies; if the rods are loose on the piston pins with little or no drag, the piston pins are worn and need replacement. If the cylinder block requires any machine work, including finish honing, the machinist will likely want the pistons on hand to check piston-to-bore clearance, a critical measurement best handled by the machine shop.

Remove the piston pin, a task best left to a dealer or automotive machine shop with the proper tools.

While the piston is still connected to the connecting rod, it should be swiveled back and forth to assess the degree of difficulty. All piston/rod assemblies should be compared; if the rods are loose on the piston pins with little or no drag, the piston pins are worn and require replacement.

The piston assembly should be pushed into the bore using a wooden hammer handle to tap the top of the piston slightly, while holding the ring compressor solidly against the cylinder block until all rings are inside the bore.

Install the bottom oil ring spacer and its components, ensuring proper gap locations for the lower and upper steel oil ring rails.

Use a ridge reamer to eliminate the ridge or carbon deposits at the top of each cylinder, working on one cylinder at a time by turning the engine to position the piston at the bottom of its stroke.

Ensure the cylinder bores are perfectly clean by wiping the cylinder walls several times with light engine oil and a clean, lint-free cloth.

If the gap is insufficient, replace the ring with another top ring. Repeat this measurement for all top rings and, if necessary, use a fine file to adjust the ends.

If the gap is insufficient, replace the ring with another top ring and check all top rings similarly, using a fine file to adjust if necessary.

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.

The piston should be examined for cracked ring lands, skirts, or pin bosses, as well as worn or wavy ring lands, scuffed or damaged skirts, and eroded areas at the top. Any damaged pistons or those showing excessive wear must be replaced.

Torque the nuts to specification and repeat the procedure for all cylinders, using the rubber or plastic tubing on each assembly to prevent damage as the pistons are pushed into place, rotating the crankshaft as necessary to make the connecting rod nuts accessible for tightening.