First insert the inner spacer (1) and then the outer bearing (2). The bearing must be inserted with a tubular drift which rests on both bearing rings (see diagram).
Lubricate the lip of the seal ring (3) and insert it in the head with the flat side facing outwards.
Insert the outer spacer (4) in the timing shaft until it stops against the bearing (2).
Position the rubber caps and tighten the retaining screws.
Position the guide washer, the key and the toothed pulley on the cam shaft.
Secure the pulley using service tool 88700.5644, insert the washer and tighten the self-locking ring nut using the bush provided with the service tool.
Caution! To prevent accidental loosening which could seriously damage the engine, use new selflocking ring nuts for securing all the timing pulleys.