Replacing Guide And Tensioning Rails

Information 

If the timing chain has to be removed or replaced, check the guide and tensioning rails as well as the chain pinions for wear and scoring and replace them if necessary.

Information 

• The rolling direction of the timing chain must always be the same. 
• If the timing chain is to be reused, the rolling direction of the timing chain must be marked before it is removed. 

1. If you have not already done so, remove upper guide rails (guide pad) between the camshafts -6-  .
   Fig 1: Identifying Timing Chain And Sprockets

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   1. Double-chain camshaft drive
   2. Camshaft sprocket
   3. Screw, M12 x 140 Tighten completely after setting timing  .
   4. Deflector rail
   5. Screw, M8 x 35
   6. Camshaft-to-camshaft guide pad
   1. Direction of travel
2. Detach tensioning rail from the threaded peg. -4- 
   Fig 2: Identifying Timing Chain And Chain Guide

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   1. Threaded peg
   2. Threaded pegs
   3. Guide rail
   4. Tensioning rail
   5. Chain tensioner with sealing ring
   6. Pin (for locking the oil-pump tensioning rail)
   1. Direction of travel
3. Carefully slacken the lower tensioning rail for the oil pump chain. Press the tensioning rail back with a small screwdriver until both staking holes between the tensioning rail and guide rail are aligned.
   Fig 3: Removing Oil Pump Tensioning Rail

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
4. Stake tensioning rail for oil pump chain through the hole in the guide rail using a suitable drill bit, drift punch or nail. This slackens the oil pump chain. →
   Fig 4: Staking Tensioning Rail For Oil Pump Chain

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
5. Remove guide rail -3-  . Tensioning rail for oil pump chain is locked with -6-  .
   Fig 5: Exploded View Of Guide Rail

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
6. Remove deflector rail -4-  by undoing the fastening screws -5-  .
   Fig 6: Exploded View Of Timing Chain And Sprockets

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   1. Double-chain camshaft drive
   2. Camshaft sprocket
   3. Screw, M12 x 140 Tighten completely after setting timing  .
   4. Deflector rail
   5. Screw, M8 x 35
   6. Camshaft-to-camshaft guide pad
   1. Direction of travel