Porsche 968 - ASSEMBLY INSPECTION PROCEDURE AND MAINTENANCE SCHEDULE Maintenance Manual page 5

2. Remove four hexagon socket head screws securing aluminium trim panel over
cam cover/fuel rail, remove "Variocam" badge and trim panel.
3. Disconnect electrical connector for Variocam solenoid. Note that spring clip
on connector should be pushed in to release. (See figure 1).
4. Remove two hexagon socket head screws securing seal retainer around
Variocam solenoid body and gently pull off seal retainer and gasket.
5. Place rags beneath connections on two fuel hoses at rear of cam cover (see
figure 1).
6. Undo both fuel line connections using 17mm and 19mm spanners. Take care
to ensure that the fittings nearest brake master cylinder are held stationary and
not twisted. Note: a few ml's of fuel will be spilled during the process, hence
the rags.
7. Gently pull fuel lines clear of the cam cover, taking care not to kink the lines.
8. Pull out spark plug caps/leads and remove spark plugs.
9. Insert clean rags into spark plug recesses to avoid risk of dropping loose
objects into cylinders.
10. Unscrew 13 hexagon socket head screws securing cam cover. Note that these
screws do not need to be removed from the cover once released but be aware
that they are not held captive in the cam cover and may drop out when the
cover is removed.
11. Gently pull on the cam cover to release its seal. It may be necessary to apply
leverage but be careful and do not insert any sharp objects between the sealing
faces.
12. When the cover is loose, gently pull away from the engine. The black rubber
seal can either stay in place on the engine, 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
removed but may pull away with the cover.
14. With the cover removed, the inspection can begin. Take great care not to drop
anything into the engine, as there are oil drain galleries below the exhaust
camshaft and screws, dirt, or small tools can easily find their way into the
engine. If this happens, you will need to remove the oil pan to recover them!
15. Using the light source and mirror, carefully and methodically inspect the upper
and lower tensioner pads, both camshaft sprockets, the metal oil pipe feeding
oil to the tensioner body, and the shiny piston rod of the upper tensioner for
wear or scoring (see figures 2 & 3).
16. These checks are very subjective, there is no test gauge or tool to measure
anything. The tensioner pads can be expected to have visible wear grooves
(the lower tensioner pad is very difficult to inspect without removing the
tensioner assembly and this requires removal of the cams). Check as far as
possible for any signs of cracking in the tensioner pads, missing pieces, or
excessive wear (see figure 4). Cracks tend to form in the corners of the pads.
Very close inspection with a strong light is required for this. Any cracks or
missing pieces will require that the pads are replaced (out of scope for this
procedure). See also the section below for further information on suggested
wear limits.