50 SENR9977 Testing and Adjusting Section Basic Engine Note: Some pistons have a tapered top groove and the piston ring is wedged. The clearance for the top piston ring cannot be checked by the above method when this occurs. i01889476 Piston Ring Groove - Inspect Inspect the Piston Ring End Gap Inspect the Piston and the Piston Rings 1. Check the piston for wear and other damage. 2. Check that the piston rings are free to move in the grooves and that the rings are not broken. Inspect the Clearance of the Piston Ring 1. Remove the piston rings and clean the grooves and the piston rings. g00983549 Illustration 56 (1) Piston ring (2) Cylinder ring ridge (3) Feeler gauge 1.
Clean all carbon from the top of the cylinder bores. 2. Place each piston ring (1) in the cylinder bore just below the cylinder ring ridge (2). 3. Use a suitable feeler gauge (3) to measure the piston ring end gap. Refer to Specifications, “Piston and Rings” for the dimensions. Note: The coil spring must be removed from the oil control ring before the gap of the oil control ring is measured. g00905732 Illustration 55 (1) Feeler gauge (2) Piston ring (3) Piston grooves i01946425 Connecting Rod - Inspect 2. Fit new piston rings (2) in the piston grooves (3). 3.
Check the clearance for the piston ring by placing a suitable feeler gauge (1) between the piston groove (3) and the top of piston ring (2). Refer to Specifications, “Piston and Rings” for the dimensions. This procedure determines the following characteristics of the connecting rod: The distortion of the connecting rod The parallel alignment of the bores of the connecting rod