Piston Rings

Ring end gap should be measured with piston ring positioned in cylinder bore at area where no piston ring wear exists. Ensure ring end gap is within specification. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS.
To check side clearance on No. 1 and 2 (upper) compression rings, use feeler gauge to measure clearance between piston ring and piston. Ensure side clearance is within specification. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS.

NOTE: No. 1 (upper) compression ring contains one identification mark and No. 2 (lower) compression rings contains 2 identification marks. Ensure compression rings are installed in correct location with identification mark toward top of piston.

Install piston rings on piston, with identification mark on piston ring toward top of piston. Ensure piston ring end gaps are properly positioned. See Fig 1.

Fig 1: Positioning Piston Rings

Courtesy of FORD MOTOR CO.

CAUTION: If rod bearing failure exists, oil cooler must be replaced and turbocharger must be checked. For replacement of oil cooler, see OIL COOLER ASSEMBLY under REMOVAL & INSTALLATION.