Porsche 968 - ASSEMBLY INSPECTION PROCEDURE AND MAINTENANCE SCHEDULE Скачать руководство пользователя страница 4

 

 

Variocam Inspection 

 
Disclaimer and Precautions: 

 
The information contained in this document is offered in good faith but the authors 
take no responsibility for any errors or omissions.  In the absence of any documented 
recommendations from Porsche, we believe that by following these steps, you should 
have better protection against catastrophic failures.  However, we cannot guarantee 
this, and recommend that you seek expert advice if you have any doubts about the 
condition of your Variocam components.   
 
Certain basic safety principles should be followed.  These include: 
 

 

Before starting work, disconnect the battery 

 

Wait until the engine has fully cooled before starting work 

 

Work in a well ventilated area and avoid naked flames or other combustion 
sources 

 
Also, when working on the engine, it’s very easy to dent the front wings (fenders) by 
leaning on them.  Place soft covers (old blankets are ideal) over them to prevent 
scratches and don’t lean on them. 

 
Tools Required:  

 

 

17mm and 19mm good quality open ended spanners (wrenches) 

 

Strong light source 

 

Old rags 

 

Inspection mirror (small dentists-type is ideal) 

 

Hexagon drive bits, sizes 4mm and 5mm, and suitable driver 

 

Spark plug socket, drive extension, and handle 

 

24mm deep 6 point socket and ratchet drive handle 

 

Torque wrench with range to cover 10 Nm / 7 ft./lbs (desirable) 

 

Parts Required:

 (assuming no repairs needed as a result of inspection) 

 
The following parts may be required if the existing items are damaged but it is usually 
possible to re-use the old parts: 
 

 

Cam cover gasket (quantity 1) 

o

 

Part number 928 104 447 09 

 

Sealing rings/grommets (quantity 4) for sealing the spark plug recesses 

o

 

Part number 928 104 443 08 

 

Inspection Procedure: 

 

1.

 

Disconnect battery. 

Содержание 968 - ASSEMBLY INSPECTION PROCEDURE AND MAINTENANCE SCHEDULE

Страница 1: ...ny necessary repair work that may be necessary as a result of the inspection findings This procedure should be suitable for all normally aspirated 968 models Also included is a suggested schedule with recommended inspection intervals These periodic inspections will provide regular checks of the health of your Variocam and its related parts and should ensure that wear or other problems are detected...

Страница 2: ...er pistons each having a plastic rubbing pad that acts directly onto the upper and lower chain runs The distance between the upper and lower tensioner pads is maintained by an internal spring supplemented by constant engine oil pressure when the engine is running This spring and oil pressure maintains correct chain tension in a similar fashion to the earlier 944 series cars The vertical position o...

Страница 3: ...effective pitch of the chain links accelerating wear of the camshaft sprockets 3 Variocam on off action As described above the Variocam is on intake timing advanced in the 1 500 to 5 500 rpm range and off outside this range The engagement of the chain with the intake exhaust camshaft sprockets differs between these two positions and this may affect the wear patterns on the sprocket teeth The weari...

Страница 4: ...rces Also when working on the engine it s very easy to dent the front wings fenders by leaning on them Place soft covers old blankets are ideal over them to prevent scratches and don t lean on them Tools Required 17mm and 19mm good quality open ended spanners wrenches Strong light source Old rags Inspection mirror small dentists type is ideal Hexagon drive bits sizes 4mm and 5mm and suitable drive...

Страница 5: ...e or stay attached to the cam cover When withdrawing the cover it s often needed to peel the seal away from parts of the engine or cover IF COVER SCREWS ARE STILL IN THE COVER TAKE CARE THAT THEY DON T FALL OUT AND DROP INTO THE EXPOSED ENGINE 13 Note that there are four black circular rubber seals around the spark plug recesses These will hopefully stay attached to the engine when the cover is re...

Страница 6: ...h is visibly worn on my old cams figure 3 and this will be accompanied by stretch of the chain It s very much a subjective judgement call as to how much wear is permissible but you should be able to spot an imminent disaster at least 23 It s a good idea to take your own close up photos if possible both for seeking second opinions and for later comparison purposes if all looks ok this time 24 With ...

Страница 7: ...spection procedure use a small mirror to carefully inspect it as much as the limited access allows Any signs of cracking more probable at pad corners means the pads need to be changed Pay attention to signs of age leading to brittle pads more prone to future cracking the age is denoted by Dark brown color of pads new ones are light brown This is not a definitive criterion but comparing fig 4 5 6 y...

Страница 8: ...tion about previous Variocam inspection maintenance as soon as possible carry out the inspection procedure detailed above Miles Km Action Unknown or greater than 60 000 Unknown or greater than 100 000 Immediately inspect the Variocam following the procedure above See also the section above regarding wear limits It is highly recommended to do the Variocam inspection before buying a new car as part ...

Страница 9: ...urposes only subject to the user accepting full responsibility for any consequences resulting from use of the information contained herein Constructive feedback comments or questions are most welcome Derek Holliday drholliday compuserve com Ugo Manfredi ugo manfredi mail wind it Issue 1 April 2003 ...

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