Piston Pins:

Centre rings: 0.40 - 0.55 mm
Lower rings: 0.25 - 0.40 mm

Piston Pins:

Piston Pin Bore in Piston:
Blue mark:23.009 - 23.005 mm
White mark:23.005 - 23.000 mm
Red mark: 23.000 - 22.995 mm

Piston Pin Diameter:

Pin colour code blue:23.005 - 23.001 mm
Pin colour code white:23.001 - 22.996 mm
Pin colour code red: 22.996 - 22.992 mm

Piston pin length: 74.00 mm

1.4.1.1. General

The pistons and connecting rods can be only be replaced when the engine has been removed from the vehicle and the transmission disconnected from the engine. New pistons and cylinder liners are matched to each other and must be kept together. This also applies to original parts, if they are to be refitted. In this case mark the pistons, connecting rods and the liner with the cylinder number.

Each piston is fitted with two compression rings and one oil control ring. The upper compression ring is chromium-plated on its outside, the second piston ring has a taper section and is therefore marked with “Top” to prevent incorrect fitting. The marking must be visible from above.

Although the pistons and connecting rods are not the same in all engines, you will find that the following description is valid for all engine types. New piston/cylinder liner assemblies mus, however, be obtain by quoting the engine number.

1.4.1.2. Dismantling Pistons and Connecting Rods

No special tools are necessary to dismantle the pistons and connecting rods. Securing rings are used to hold the piston pins in position. Proceed as follows to dismantle:

• Use a pair of piston ring pliers and remove the piston rings one after another from the crown end of the piston, as shown in Fig. 1.64. If no piston ring pliers are available, use three thin metal strips and slide the rings over the strips to remove them one by one. One of the strips must be placed underneath the piston ring ends to avoid scratches.
• Remove the securing rings out of the two piston pin bores. Either use a small screwdriver or a pair of circlip pliers for this operation.
• Use a stepped mandrel to drive out the piston pin. Hold the piston in

Fig. 1.64. — Removal of piston rings.