PISTONS AND CONNECTING RODS-F.S Where pretopped pistons are used, then the piston height can be slightly lower than the limits given. It is important to note that where vehicle engines have to conform to the smoke density regulation B.S.AU 141 a: 1971, then the piston height production limits must be maintained. It will of course be appreciated that grade F pistons are suitable for topping to give other grades where these are not to hand. After fitting pre-topped pistons, the distance between the cylinder block face and p:ston crowns should be checked to ensure the limit is as already quoted (See Fig. F.12).
4.108 Vehicle Engines Production Grade A to F G to L M to P Equivalent Service Grade F L P 4.99 Engines Production Grade B, D, & F H, J, & L N & P Equivalent Service Grade F L P F12