Fitting Pistons
- With cylinder bore cleaned, measure for taper or out-of-round with a suitable cylinder gauge. If cylinder is tapered or out-of-round more than 0.0008" (0.02 mm) or if the cylinders differ in size more than 0.002" (0.05 mm), cylinders must be rebored for oversize pistons.
- Measure piston diameter with a feeler gauge at right angle to piston pin axis. If clearance between piston and cylinder bore exceeds 0.008" (0.2 mm), cylinders must be rebored and oversize pistons installed. Pistons are available 0.010" (0.25 mm), 0.020" (0.50 mm), 0.030" (0.75 mm) and 0.040" (1.0 mm) oversize.
- Check ring clearance in piston ring groove with a feeler gauge. If ring side clearance is excessive, ring groove is worn and piston must be replaced. Check ring end gap in cylinder bore with a feeler gauge. If cylinder bore is to specification and ring gap exceeds specifications, rings must be replaced.