Piston, Connecting Rod, and Bearings Cleaning and Inspection

WARNING: This page is about a different car, the 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Clean the piston and connecting rod in solvent.
Dry the components with compressed air.
Clean the piston ring grooves with a suitable ring groove cleaning tool.
Clean the piston oil lubrication holes and slots.

Fig 1: Piston Pin And Retainer
Courtesy of GENERAL MOTORS CORP.
Inspect the piston for the following conditions:
- Eroded areas (1) on top of the piston
- Scuffed or damaged skirt (2)
- Damage to the pin bore (3)
- Cracks in the piston ring lands, the piston skirt, or the pin bosses
- Piston ring grooves for nicks, burrs, or other warpage which may cause the piston ring to bind.
Inspect the piston for scoring, wear or other damage.

Fig 2: Inspecting Piston
Courtesy of GENERAL MOTORS CORP.
To determine the piston-to bore clearance, use a micrometer and measure the piston pin.

Fig 3: Piston-To Bore Clearance
Courtesy of GENERAL MOTORS CORP.
To determine the piston pin-to bore clearance, use an inside micrometer and measure the piston pin bore.
To determine the piston pin-to-bore clearance, subtract the piston pin diameter from the piston pin bore diameter.

Fig 4: Piston Pin Bore Diameter
Courtesy of GENERAL MOTORS CORP.
Inspect the connecting rod for an out-of-round bearing bore.

Fig 5: Inspect The Connecting Rod For An Out-Of-Round Bearing Bore
Courtesy of GENERAL MOTORS CORP.
Inspect the connecting rod for twisting.

Fig 6: Inspect The Connecting Rod For Twisting
Courtesy of GENERAL MOTORS CORP.
Inspect the connecting rod cap bolts for stretch (compare to known good bolt) (1) is a stretched bolt, (2) is a new or good bolt.

Fig 7: Inspect The Connecting Rod Cap Bolts
Courtesy of GENERAL MOTORS CORP.