VIN 04233 to 15435 Turbo models only 8:1 CR

All Mulsanne Turbo, Turbo and Turbo R models before VIN 20000 were fitted with 8:1 Compression ratio pistons.
Before VIN 15436 Turbo models were fitted with the piston rings that are listed below. The part number on the pistons that accept these rings is UE45568.
UE46312 is the superseded part number as supplied by Bentley.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.