Cleaning and Inspection

CAUTION: Do not use a caustic cleaning solution or a wire brush to clean pistons (6108) or damage may occur. Use care not to scratch the pistons.

CLEANING
Clean the ring grooves with Piston Ring Groove Cleaner D81L-6002-D or equivalent. Do not cut into the piston metal. Carbon may be cleaned from the top of the piston (6103) with a wire brush or wheel. Do not use a wire wheel on the piston ring grooves or lands. Clean the oil drain holes in the oil ring grooves. Do not drill additional oil drain holes. Clean the remainder of the piston with solvent and a brush. Do not use a caustic (Lye base) or acid cleaning solution.

INSPECTION
Inspect The Piston For - scores, cracks, excessively worn piston pin bores, pitted or eroded dome, worn piston ring grooves, and piston skirt diameter. Carefully inspect the pistons for fractures at the ring lands, skirts, and pin bosses. Check for scuffed, rough, or scored skirts. If the lower inner portion of the ring grooves have high steps, replace the piston. This step will interfere with piston ring operation and cause excessive piston ring side clearance.

Spongy, Eroded Areas - near the top of the piston are usually caused by detonation or premature ignition. A shiny thrust surface, offset from the centerline between the piston pin holes, can be caused by a bent connecting rod (6200). Replace pistons showing signs of excessive wear, irregular or fractured ring lands, or damage from detonation and premature ignition.

Inspect the Outer Circumferences - of all pistons for seizure or scoring. Replace the piston if damaged.

Inspect lower lands - If lower lands have high steps, piston should be replaced.

FITTING
Check the piston-to-cylinder bore clearance by measuring the piston and cylinder bore diameters. Service as required. Check Ring to ring groove clearance and ring end gap. Follow the proper procedure. Service as required. Check the piston pin fit in the piston and connecting rod. Service as required. Check connecting rods for bends or twists if necessary.