Rear Drive Belt - Oscillation or Damage
85porsche01Subject:
Rear Drive Belt Cover
Model
944
Group
1
Part Identifier
1531
Number
8504
February 19, 1985
Drive belt oscillation can occur at critical engine speeds when the belt is insufficiently tightened and could then be damaged by hitting the reinforcement ribs of the rear drive belt cover.
The reinforcement ribs on the rear drive belt cover, in the area of the camshaft sprocket have been reduced in size.
As of March 1984 Engine # 43 E 09856 - Manual 43 E 21233 - Automatic
Diagnosis and Repair procedures for cars before the above engine number:
1. Signs of Camshaft Drive Belt Damage
A) -Teeth torn on one side or both sides of tooth base (root). -Teeth ground off at an angle or straight on tooth head (tip). -One or more teeth broken.
Modify drive belt cover (see # 2) and replace drive belt.
B) -Belt face smooth or glossy. -Belt running on side of tooth collar or coolant pump collar. -Belt has cuts in sides occassionally or cut in longitudinal direction. -Belt not resting completely on sprocket.
Then the tensioning roller is running on an angle. Modify as per Technical Bulletin Group 1, #8502. Replace drive belt if needed.
2. Drive Belt Cover
When replacing drive belts or performing repairs in which the cover is accessible, the (old) cover should be modified as shown in the drawing, using a flexible shaft grinder, chisel, etc.
CAUTION! Drive belts, sprockets and rollers in the working area must be covered when machining the ribs to protect them against damage. All ground off/chiseled off material must be removed.
The removal of the cover is not necessary unless the drive belt has to be replaced.
The time specified for grinding off the ribs with the cover installed is 20 T.U. Refer to the SRT microfiche for the remaining operations.
Only the new version covers are available for replacements.
Repair Manual Cross Reference for the above operations:
Type 944 - Volume 1
Description Group Page
Adjusting balance shaft timing 13 45-51
Adjusting balance shaft drive belt 13 3-5 & 7-12
Adjusting alternator polirip belt 13 1
Adjusting power steering belt 13 2
Adjusting camshaft timing 13 5-6
Adjusting camshaft drive belt 15 1-4
Tightening torque specification 15 03-06