Mack Trucks — 5-101.bk

5-101.bk Page 16 Friday, March 17, 2006 11:05 AM For a new ring and piston, oil ring side clearance is 0.0016–0.0030 inch (0.0406–0.0762 mm). For an old ring and piston, the clearance should not exceed 0.0045 inch (0.1143 mm). POSITION GAUGE IN RING GROOVE WITH GAUGE PINS ALIGNED WITH WRIST-PIN BORE. 6. Perform step 5 on each piston. MEASURE DISTANCE ACROSS PISTON AT GAUGE PINS (PARALLEL TO WRIST-PIN BORE). REPOSITION GAUGE 90 DEGREES AND MEASURE ACROSS PISTON AT GAUGE PINS (PERPENDICULAR TO WRIST-PIN BORE). 201063a Figure 5-14 — Side Clearance Measurement Figure 5-13 — Ring Groove Wear Measurement 4. Perform steps 1, 2 and 3 on each piston. Refer to Figure 5-14. 5. Check oil control ring.

a. Using a thickness gauge, check for excessive wear of oil control ring groove side clearance (1). Position a new oil control ring in groove and insert a thickness gauge between ring and upper land of groove. b. Record measurement and compare reading with Fits and Limits chart to see if it is within tolerance. Page 5-16 200 BENCH PROCEDURES