Procedure for Cylinder Block Assembly Piston Replacement - 9000 Hatchback Engine
Piston: Service and Repair
General
Fig. 7 Piston & Connecting Rod Installation
The type pistons used varies with the engine compression ratio. Either Mahle or Kolben-Schmidt pistons may be fitted to the engine, but pistons of
different makes should not be installed in the same engine as an imbalance condition may be created.
Pistons and rings are available in standard, 0.020 inch (0.5mm) oversize and 0.040 inch (1mm) oversize. Standard size pistons are supplied in 3
different size classes, and all pistons and cylinder bores should be measured prior to installation. Pistons should be measured at right angles to the piston
pin hole at a point 0.63 inch (16mm) above lower edge of skirt for Mahle pistons, or 1.03 inch (26mm) above edge of skirt for Schmidt pistons.
Measure piston installation clearance using a spring gauge and feeler gauges 1/2 inch wide. Clearance should be measured with piston installed in a
lightly oiled bore, without rings, at right angle to piston pin bore. When indication on spring gauge used to pull feeler gauge between piston and bore is
1.8-2.6 lbs., piston clearance is equal to the thickness of the feeler gauge used.
Piston ring gap should be measured in the finished bore, using feeler gauges. Push each ring into bore using an inverted piston to properly position
rings. New rings fitted to a worn cylinder bore should be checked at the bottom of the piston travel, as the cylinder will be narrowest at this point.
Install piston and rod assemblies with FRONT mark or notch pointing toward timing cover, Fig. 7. Piston and rod should be assembled so that
reference stampings on connecting rod, Fig. 7, face exhaust side of engine. Use a piston ring installation tool to position the lower compression ring with
the side marked ``top'' uppermost. Rotate compression rings so that gaps in alternate rings are 180° in relation to each other, positioned over the ends of
the piston pins. Make sure that the ring gaps of the top and bottom rings in the three piece scraper ring are staggered.
