VIN 01001 to 16076 8:1 CR

All cars for North America, Japan and Australia (except Turbo models) were fitted with 8:1 Compression ratio pistons.

Before VIN 16077 cars for North America, Japan & Australia were fitted with the pistons and rings shown below. The part number on the pistons that accept these rings is UE45566.
UE46310 is the superseded piston assembly as supplied by Bentley.

The Workshop Manual TSD2476 states that the cylinder liner diameters should be checked with a dial test indicator. If they are worn more than 0.1016mm (0.004") or if the ovality exceeds 0.076mm (0.003") it is necessary to fit new liners and pistons.