Connecting Rods and Pistons/Pistons and Connecting Rods 19. Inspect cylinder bores for scuffing, scoring, scratches, cracks, and wear. If cylinder bores are damaged, replace cylinder block or rebore and hone cylinder for next oversize piston. 20. If the cylinder bore is not damaged, check cylinder bore for wear. M36401 -UN-29JAN90 M98,2030K,32 -19-09OCT85 CTM2 (19APR90) 30-19 16, 18, 20 & 24HP Onan Engines AllTractorManuals.com 130495 17. Measure piston O.D. perpendicular to piston bore at a point approximately 30 mm (1.2 in.) from top of piston or 2.5 mm (0.1 in.) below oil ring groove. NOTE:
If engine has had a previous major overhaul, oversize pistons and rings may have been -UN-29JAN90 installed. PISTON SPECIFICATIONS Item New Part Wear Tolerance M36400 Piston O.D. B43E, B43G, B48G, P218G, P220G 82.42—82.44 mm 82.32 mm Engine (3.245—3.246 in.) (3.241 in.) T260 Engine 90.42—90.45 mm 90.32 mm (3.560—3.561 in.) (3.556 in.) If piston diameter is less than wear tolerance, install a new piston. 18. Inspect piston for cracks at ring lands, skirts, and pin bores. Inspect piston for scuffing or scoring; replace as necessary. M98,2030K,31 -19-02FEB87 30 19