to replace the distributor cap and the rotor on a 993
(9 pictures to download)
Just like the spark plug the distributor
cap and rotor needs to be replaced on a regular basis. You should replace it every
other time you replace your spark plugs. Since my 993 have accumulated 28,000 miles
I feel now it is a good time to replace it. Most newer cars now days have electronic
ignition without distributors, the reason why Porsche still uses the mechanical
distributor system for the 993 is unknown. But Porsche changed to the newer
distributor less system on the 996.
If you have any doubts
about replacing your distributor cap, take a look at this below picture of my distributor
cap at 28,000 miles. The picture clearly shows the oxidation and the arching damaged
from the high voltage sparks. Click on the picture to get a closer view.
First step in replacing the
distributor cap is to remove all the ventilation ducts that is blocking your way.
First step is to remove the two 10 mm bolts that hold the upper duct in place.
Pull the the temperature
sensor from the upper duct housing by squeezing the metal clip. Remove the upper air
Loosen the 1st strap on the
Loosen the 2nd strap screw
After removing the heater
coil element and the white robber ventilation hose for the distributor belt the lower air
duct can now be completely removed
The distributor is held on by two philips
screw, the screw is on very tight so be careful not to stripped the screws. I
stripped the lower screw on the bottom distributor cap and had a hell of time removing
it. Actually I have to remove the muffler, the muffler mounting bracket, remove the
engine shroud, remove the heat exchanger pipe mounting screw that goes into the
ventilation pipes. It was not fun. Since I was planning to change out the
spark plug next I had to take most of these parts off any ways. But you want to be careful
on the lower screw on the bottom distributor, it is at a awkward angle to get to.
Here is a picture of the
After loosen the
distributor screw you first remove the cap with the spark plug wire still on it and
replace the rotor that is underneath it. There is no trick to that just pull off the
old one and push in the new one. There is a notch on the distributor shaft so there
is no possibility of putting in the rotor incorrectly.
Place your new distributor cap next to the
old one and replace the spark plug wires one by one, I know there is very little room to
work with there, but I did it like that. This way you eliminate any possibility of
hooking up the spark plug wire to the wrong post.