Engine - Modified Components
85porsche01Subject:
Camshaft Drive Belt
Model
944
Group
1
Part Identifier
1524
Number
8502
April 26, 1985
Attention: This bulletin supercedes Group 1, Number 8502, issued March 18, 1985.
The drive belt tensioning roller mounting on the oil pump body has been changed in order to maintain better belt alignment.
Misalignment could cause the camshaft drive belt to run off-center, resulting in premature wear of the drive belt.
Change I
As of Sept. 3, 1984 Engine # 43 E 14859 - Manual 43 E 21784 - Automatic
The mounting boss on the oil pump body for the drive belt tensioning roller was shortened by 13 mm and a collar bolt with a larger contacting surface is used instead of the regular stud.
The oil pump was modified at the same time to increase the delivery rate, and the oil intake bore in the crankcase lower section was increased in diameter.
Change II
As of Sept. 14, 1984 Engine # 43 F 40461 - Manual 43 F 50077 - Automatic
The collar bolt has been superceded by a stud and a collar nut for easier installation.
Parts Summary:
For engines produced prior to Sept. 3, 1984: When replacing the pump, order part # 944.107.014.05. This is the original pump with modified mounting. Also order stud, # 944.102.216.01 and collar nut # 944.102.243.00.
For engines produced after Sept. 3, 1984:
when replacing the pump, order part # 944.107.014.08, stud # 944.102.216.01 and collar nut # 944.102.243.00.
The collar bolt used during Change I is not available as a spare part, and if needed, should be replaced with stud # 944.102.216.01 and collar nut # 944.102. 243.00.
Condition:
Camshaft Drive Belt running on an angle. Engine produced prior to Sept. 3, 1984.
Diagnostic Procedure:
Check toothed belt alignment with the upper belt cover removed and with the engine running.
CAUTION! Great danger of an accident! Keep hands, fingers, long hair and clothing out of running belt.
A drive belt which runs on an angle can be identified as follows:
- Tears or cuts in lengthwise direction of belt.
- Smooth or glossy sports on sides of belt.
- Belt scraping on sprocket collar or collar on coolant pump sprocket
- Belt not resting completely on sprocket.
Repair Procedure: To correct belts which run on an angle:
1. Turn engine to TDC for cylinder #1.
2. Remove pulley, drive belt, sprockets and tensioning rollers, as well as the rear drive belt cover and distributor cap with console.
3. Loosen oil pan bolts and lower oil pan approximately 10 mm. Lowering the oil pan is necessary to avoid damaging the rubber seal between the oil pan and oil pump body
4. Remove and disassemble completly the oil pump.
5. Remove old stud for tensioning roller and clean threads in housing.
6. Machine oil pump body boss reducing the thickness to 30 +/- 0.2 mm as shown in the photo, with a 25 mm dia. milling cutter.
IMPORTANT: An upright drilling press must be used for this work to maintain parallel planes.
7. Degrease short threaded portion of the new stud and coat with Loctite No. 270, then install stud into crankcase. The stud must project approx. 80 mm.
8. Seal oil pump internally as outlined in Technical bulletin Group 1, # 8501 and install a new crankshaft seal.
9. Reinstall modified oil pump.
10. Screw on collar nut with the collar facing the oil pump body and torque to 45 N-m (32.4 ft.lbs.)
11. Reinstall bolts. Retorque in sequence and check the engine oil level.
12. Reinstall pulley, drive belt, sprockets, tensioning roller, rear belt cover and distributor cap.
13. Adjust timing of camshaft and balance shafts. Check and adjust tightness of belts. As per following specification:
Camshaft - 2.7 +/- 0.3
Balance shaft - 4.3 +/- 0.3 (new belt) 4.0 +/- 0.3 (used belt) Guide roller slotted:
2.7 +/- 0.3 (new and used)
Alternator - 9.5 +/- 0.3 (new and used)
14. Start engine and check belt running position.
15. Reinstall upper drive belt cover.
NOTE: Since the above procedures require the removal of the rear belt cover, the reinforcement ribs of this cover in the area of the camshaft sprocket must be machined. As shown in Technical Bulletin Group 1, # 8504.
The time specified for machining of the oil pump body boss, with the oil pump removed, and replacing the tensioning roller stud is 40 T.U. For all other operations refer to the SRT microfiche.
Repair manual cross references for the relative repair procedures are contained in Volume 1, Type 944:
Description Group Page
Removing and installing oil pump 17 3-11
Mounting oil pan 17 13
Adjusting balance shaft timing 13 45-51
Adjusting balance shaft drive belt 13 3-5 & 7-12
Adjusting alternator polyrib belt 13 1
Adjusting power steering pump belt 13 2a
Adjusting camshaft timing 15 5-6
Adjusting camshaft drive belt 15 1-4
Tightening torque specifications 10 03-06