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Distributor Removal and Belt Replacement
 
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Pelican Technical Article:

Distributor Removal and Belt Replacement

Steve Vernon

Time:

2 hours2 hrs

Tab:

$10

Talent:

****

Tools:

13mm socket, Philips and flathead screwdriver, punch, small picks

Applicable Models:

Porsche 993 Carrera (1995-98)
Porsche 993 Carrera 4 (1995-98)
Porsche 993 Carrera 4S (1996-98)
Porsche 993 Carrera S (1998)
Porsche 993 Targa (1996-98)
Porsche 993 Turbo (1996-97)

Parts Required:

Distributor caps, rotors

Hot Tip:

Change both caps at the same time

Performance Gain:

More power

Complementary Modification:

Change spark plugs

The 993 is a flat six cylinder engine that is the first Porsche mass produced engine to be twin plugged. This means that there are two spark plugs for every cylinder. While the motor is the first twin plugged motor, it runs off of a single distributor shaft that connects to a gear on the intermediate shaft and then drives a second distributor rotor by a belt off of the first distributor. If that belt fails the second distributor will not distribute any spark.

To test if your belt is working fine, pull the distributor cap off your secondary distributor. Can you spin the rotor with your finger? If so, the belt inside doesn't have a grip on it, and the belt is stripped or broken. You can also pull the coil wire to the primary distributor. Start your car with it disconnected. If the car starts and runs on distributor two, which is turning because of the belt connected to the primary distributor, then the belt is OK.

Replacing the belt is not an easy job as the area inside the distributor where you will be working is very tight and you need to make sure that the two distributors are lined up exactly at Top Dead Center or the number one firing positions when you get the belt on, if not you need to remove the belt and try again. This can take a few tries but if you have some patience you will get it.

Since everything needs to be lined up precisely it is a good idea to set your motor at Top Dead Center before starting. Please see our article on how to set your engine at TDC for additional instruction.

If you own a Varioram car you will need to remove part of the blower motor assembly (red arrow) and you may need to move the A/C lines (yellow arrow) if needed.
Figure 1

If you own a Varioram car you will need to remove part of the blower motor assembly (red arrow) and you may need to move the A/C lines (yellow arrow) if needed. Please see our articles on these procedures for additional assistance.

On the non-Varioram engines the blower motor assembly is located on the left side of the engine and you will need to remove the heat tube (red arrow) to remove the distributor caps.
Figure 2

On the non-Varioram engines the blower motor assembly is located on the left side of the engine and you will need to remove the heat tube (red arrow) to remove the distributor caps.

Label all of the plug wires so you can reinstall them after.
Figure 3

Label all of the plug wires so you can reinstall them after. Make sure to denote whether the wire goes to the upper of lower distributor. The firing order is the same for both distributors and is inscribed on the top of the cap. Remove the wires from the caps once everything is labeled, do NOT pull the wires off by the wire but by the base. Use a Philips head screwdriver and remove both caps.

Pull the rotors straight up and off the distributor shafts.
Figure 4

Pull the rotors straight up and off the distributor shafts.

Remove the dust covers.
Figure 5

Remove the dust covers. These have a dimple on the edge that will sit in a cut out in the base and can only be installed correctly in one direction.

Disconnect the wiring from the side of the distributor by squeezing in on the clip (red arrow) and pulling it off.
Figure 6

Disconnect the wiring from the side of the distributor by squeezing in on the clip (red arrow) and pulling it off.

Use a 13mm socket and remove the bolt holding the distributor to the block (red arrow).
Figure 7

Use a 13mm socket and remove the bolt holding the distributor to the block (red arrow). The base of the distributor can only go on one way and there is no adjustment (unlike older 911 distributors) which is one of the reasons why everything has to line up exactly.

Remove the tube from the distributor by just wiggling it off (red arrow).
Figure 8

Remove the tube from the distributor by just wiggling it off (red arrow).

There is an O-ring at the base of the distributor that can cause issues with pulling the distributor out from the case, especially if it has not been removed in a long time.
Figure 9

There is an O-ring at the base of the distributor that can cause issues with pulling the distributor out from the case, especially if it has not been removed in a long time. We had to pull the alternator, fan and fan housing out so we could safely help (pry) the distributor out.

If your distributor is stuck remove the fan housing and use a pry bar between the case and distributor and pry it out (red arrow).
Figure 10

If your distributor is stuck remove the fan housing and use a pry bar between the case and distributor and pry it out (red arrow).

Pull the distributors out and take it to your work bench.
Figure 11

Pull the distributors out and take it to your work bench.

The belt on our distributor was broken but if you pull your dust caps and see this type of small black rubber built (red arrow) up inside the housing your belt is on its way out and you should replace it.
Figure 12

The belt on our distributor was broken but if you pull your dust caps and see this type of small black rubber built (red arrow) up inside the housing your belt is on its way out and you should replace it.

Using a small flathead screwdriver gently pry up the metal retaining clip inside the housing holding the wiring mount in place.
Figure 13

Using a small flathead screwdriver gently pry up the metal retaining clip inside the housing holding the wiring mount in place.

Separate the wiring from the mount and slide the wiring back into the distributor body so you can remove the shaft.
Figure 14

Separate the wiring from the mount and slide the wiring back into the distributor body so you can remove the shaft.

Depending on whether the belt on your distributor has been replaced before will determine if you need to drill out or tap out the pin at the bottom.
Figure 15

Depending on whether the belt on your distributor has been replaced before will determine if you need to drill out or tap out the pin at the bottom. Ours was a mushroomed mess and we had to drill it out.

You will need to pull the gear off the end of the shaft as it is pressed on there pretty tight; I found a cheap ball joint separator worked great though you will need to use a very small socket between the end of the separator and shaft to get it all the way off.
Figure 16

You will need to pull the gear off the end of the shaft as it is pressed on there pretty tight; I found a cheap ball joint separator worked great though you will need to use a very small socket between the end of the separator and shaft to get it all the way off.

Make sure you note the number and orientation of the washers between the gear and housing and install in the same number and orientation when reinstalling.
Figure 17

Make sure you note the number and orientation of the washers between the gear and housing and install in the same number and orientation when reinstalling.

Use a small Philips head screwdriver and remove the three small Philips screws inside the primary distributor (red arrows).
Figure 18

Use a small Philips head screwdriver and remove the three small Philips screws inside the primary distributor (red arrows).

You can now lift the shaft and assembly out from the housing.
Figure 19

You can now lift the shaft and assembly out from the housing. There will be washers below the drive sprocket (red arrow) and base of the housing, make sure to also note the number and orientation for reassembly.

In this photo you can see the broken belt.
Figure 20

In this photo you can see the broken belt. Next use a 5mm Allen and remove the five Allen bolts (red arrows) holding the tow case half together.

Rotate the secondary shaft assembly until it clears the small dowel pin that holds the cases in place (red arrow).
Figure 21

Rotate the secondary shaft assembly until it clears the small dowel pin that holds the cases in place (red arrow).

Flip the housing over and slightly tap the dowel (red arrow) into the upper half until it clears the bottom half.
Figure 22

Flip the housing over and slightly tap the dowel (red arrow) into the upper half until it clears the bottom half.

You can now lift the housings and separate them enough to remove the old belt and install the new one.
Figure 23

You can now lift the housings and separate them enough to remove the old belt and install the new one. Installation is the reverse of removal but you MUST make sure that the shafts line up in the number one firing position at the same time. It is a very tight area to work in and the new belt will be a tight fit but take your time and it will eventually work. You will need to help the belt on from above and below depending on what works best for you, just remember that if the rotors are not both lined up at #1 at the same time you'll need to do it over. Good luck!

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