49 4 DLT ENGINE PISTONS AND PISTON RINGS Remove piston rings from piston using ring expander. Refer Figure 77 Remove carbon deposits from piston. Clean piston and piston rings thoroughly. In case cylinder bore taper and ovality is within specified limit, then same pistons and piston rings may be reused. Examine pistons for cracks, scoring, other damages, ring groove wear, piston pin bore wear, spring clip groove wear/damage etc. In case of any one piston with any one of this defect, complete piston set should be replaced. Examine piston rings for scoring, lateral clearance in piston ring groove and butt clearance in cylinder bore. Refer Figures 78 & 79 BUTT CLEARANCE OF PISTON RING SHOULD BE MEASURED INUNWORN PORTIONOF CYLINDER BORE. In case of any piston ring with any one of this defect, complete ring set should be replaced. When cylinder bores are re-bored or honed, pistons and rings of appropriate size should be used. Piston grade as per size is stamped on piston crown. Install piston rings in their respective position on piston using ring expander. Refer Figure 80 Stagger piston rings gaps such that they are 1200 apart. Fig. 78 Fig. 79 Fig. 80 Fig. 77
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