The Twin Distributor S2 belt-

  • Normy1
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20 Apr 2013 19:03 #14407 by Normy1
The Twin Distributor S2 belt- was created by Normy1
The '84-'86 ROW cars used the 2-valve V8 engine. In this case, with higher compression and longer duration cams. These would NOT meet US emissions at the time, so most of the "Grey Market" cars have been seriously molested. Astute owners returned them to European spec, and that is the car that I have.

In 1984, Porsche was at a quandary with the 928 car. They had a new 32 valve engine, and though it was a big leap forward performance wise over their American-spec 2-valve engine of 234 hp, It's advanced systems created problems on the assembly line. Their solution: To use the 4 valve ignition system on the 2 valve engine. Problem: The 4 valve ignition, known as EZF, requires one distributor per four cylinders. Porsche was already using EZF on their 944/951, which was basically the same engine anyway.

Problem solved: Use two 944 distributors on this strange mount that was used originally on some odd 911 Turbo. I guess it was for a twin-plug flat 6; In any case the two 944 distributors work just fine on the M28-21 V8 in my garage.

Tonight, I changed the tiny belt that connects the front distributor to the rear. It was a BITCH! Taking the old one off wasn't a problem, just use a small screwdriver and slowly work it off. Installing the new one:

Here's how you do it:

1. First of all, make sure that you MARK DOWN where the rotor was on the front distributor!

THIS IS IMPORTANT! The front distributor is EVERYTHING if you want your car to run right!

Make a mark with a marker EXACTLY in the center of the front rotor. The belt can't be off by a tiny bit- it will be off gigantically if you don't get it right. So it isn't hard to get it right- Just put the front distributor in plance and try to work the belt down around it. Remember, the ignition timing on this engine is by COMPUTER, not by the distributor, that is why the rotor's contact is almost an inch long.

2. Place the belt around the rear distributor, and slowly try to work the "teeth" of the belt down around the sprocket. If you leave the belt half-hanging off the rear sprocket, you'll find it easier to slip the toothed belt over the front sprocket, and use a small screwdriver to slowly push it down.


When removing the two caps, I found lots of carbon fouling. I wonder about this, but an aviation mechanic that I talked to who owns several classic cars asked me about my system voltage. According to him, on 1980's cars it is typical to find this fouling on cars with low system voltage. I have checked my car at the battery with a Fluke multi-tester, and I've found 13.7 volts consistently. That is exactly what the alternator is designed to deliver.

In order to remove the tiny rubber belt, you need to remove the two "caps". The WSM's call for you to use a "bearing puller" to pull these. I simply used a very large channel locks to remove these "hats", and then used a deep socket to put them back in place . You are supposed to replace these "hats". I didn't; I guess I am going to live dangerously~

They bent up a little bit when I removed them. I bent them back down and used a socket to put them back in place.

I drove the car around tonight, it ran just fine. That belt looked like it had been there for 20 years! I can use it for a bracelet, but it is too loose. I tried to use it as an "anklet", but I cannot get it around my heel. I decided to put it on the light that I have above my desk; "I went 150 mph with that as a part of my engine"~


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20 Apr 2013 21:06 #14412 by 928mac
Replied by 928mac on topic The Twin Distributor S2 belt-
There are a few Bitch jobs on these cars.
Glad you got it fixed.
Hey thats 2 more cars running today, yours and mine. :)

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