Distributor service (Clean and lube) real easy without removing the pinion gear!

[Gunter]

Once you see the dirt inside, you'll be glad you did!



This one is a Bosch 0 237 304 016 from a Porsche '82 SC ('80-'83 are the same).
The '78-'79 distributors 0 237 306 001 are identical, except for the vacuum advance which is 1 237 122 035.
SC-distributors are very similar but, Carrera distributors are slightly different.
Items needed:
A small container to keep the parts.
Small circlip-pliers for external circlips. (Highly recommended!)
2 good-size flat screwdrivers 8-10" for prying.
Small drift and hammer.
3mm Allen key.
Oil and several rags.
Cleaning fluid and small brush.
No beer.

Set crank pulley to Z1, remove cap and just put it out of the way with wires in place. Check that rotor points to the notch in the distributor housing. To ensure that it is at the compression stroke, remove the valve cover left side and wiggle the intake valve; it should be lose! If not, turn the engine clock-wise 180 deg to Z1.
Remove hold-down nut and pull out distributor. It may be tight, pry on it; a small pry-bar using the short end under the distributor for leverage.
With the distributor out:
Remove the 2 clips for the cap.
Remove the small felt inside the shaft and ignore the screw inside.
Remove the Vacuum Advance Mechanism (2 screws) with a slight upward movement and wiggling the inside connector arm downward at the same time.
Remove the circlip on the shaft the easy way: With circlip pliers if it has the eyelets. Some circlips don't have eyelets; use 2 small screwdrivers carefully to remove it and don't let it fly into space.
With soft jaws, or small pieces of plywood, in the vice, clamp the distributor on its bottom.
With two 8-10" flat screwdrivers set across from each other on the edge of the distributor, pry under the Timer Core (811) with equal force upwards and remove it. It might be tight! Use some penetrating oil on the shaft. (WD-40 is NOT penetrating oil!)
IMPORTANT: Don't lose that very, VERY small dowel pin in the groove as the Timer core comes up!

Remove the second circlip from the shaft.
There may be additional washers on the shaft, save them and keep track for re-assembly.
Scratch a match-mark for reference on the Magnetic Pulse Generator (805) in relation to the notch in the distributor housing.
The 3 cut-outs (Notches) at the edge of the Magnetic Pulse Generator (805) are there so you can insert a 3mm Allen key. Use a light and turn the assembly if necessary to find the 3 Allen screws. Clean the inside of the hex with a piece of wire so the Allen key can go in all the way. Unscrew the 3 screws completely and lift out the whole assembly.
Now you'll see the weights and springs and all the dirt and grime!
Use your favorite cleaning fluid in a small container, submerge the distributor upside down and let it soak for a while. Use the small brush to clean the inside and weights thoroughly.
Clean all other parts.
I left the Magnetic Pulse Generator (805) and the Coil Section (807) connected for cleaning and oiling. Penetrating oil really gets into the bearing for cleaning, follow up with oil.
If things look good, oil the springs and pivot-points for the weights and re-assemble.
Oil the whole shaft on the outside.
Use the match-mark to install the Magnetic Pulse Generator but don't tighten the 3 Allen screws completely, just snug.
Install the circlip.
When installing the Timer Core, place the small dowel pin in its place on the bottom of the groove first, (Distributor on an angle in the vice, with the groove pointing up), then tap the Timer Core down with a small drift making sure that the roll pin stays in place. Use a little oil.
Install the last circlip.
Turn the shaft and make sure that the Timer Core rotates freely meaning: The star-tips do not touch the tips on the Pulse Generator.
Center the Pulse Generator before you tighten the 3 Allen screws.
It should spin freely now.
A few drops of oil in the shaft-center, replace the small felt plug, that's it.
Check the vacuum diaphragm.
With a line on the advance nipple, suck on it and watch the mechanism move.
Use your tongue to hold the vacuum for a few seconds. Good? O.K.
Install the distributor using the notch in the housing again for the rotor as a reference for installing; pulley still at Z1.
Start the engine; check and adjust the timing per specs.
Advance vacuum line connects in the rear of the TB.
Now put a grin on your face and tell your girl friend how good you are.
To complete the mission, test the ignition harness for leaks and the right resistance values:
The Beru plug connectors should show ~3k OHMS.
The short cap connectors are 1k OHMS.
Check each wire from end to end: ~4 OHMS total resistance; anything else means a problem.

I refurbished a couple distributor and found that the bushings, weights and springs were remarkably good even with 200k miles but the dirt in them is unbelievable.
I recommend the use of the dust shield (19) available on PP.
The axial play can be controlled by replacing/installing washers.
If you need to replace some washers under the pinion gear, remove it by carefully grinding the pin flush on one side and tap it out with a very small drift.
Mark the position of the gear on the shaft to be safe; use penetrating oil.
You can make a new pin out of long rivets, or nails, or buy a tight-fitting roll pin.
PP sells the pin, gear and vacuum advance for '78-'79 and '80-'83 as well as cap, rotor and signal cable connector (Pig-tail)

[Early_S_Man]

Good show, Gunter! Untold numbers of SC owners will be glad to see that diagram!

Here are a couple of magnetic pickup coil assemblies that are available at NAPA stores:



http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=BA&PartNumber=1800144&Description=Distributor+Pick-Up+Assy

http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=ECH&PartNumber=MP304&Description=Distributor+Pick-Up+Assy

[brendon]

Subscribed.

Nice work.

[pjv911]

I would love to buy a replacement set of holding springs (part 9 in picture) . I typed the shown Bosch part # in on pelicans database but as usual it comes up with 10 others things instead of the spring. How can I effectively buy these ? Any help would be much apprieciated at this point. My distributor has been missing one for 3 years. They seem to break faily easy.

Kurt Williams

[Gunter]

Kurt:
The parts list came from Bosch USA by E-mail in pdf-format after some phone calls. I was told that Bosch Germany has only supplied the list for electronic parts and the vacuum advance.
Bosch USA has no list for other parts like shaft, weights, springs, gear etc.
My suggestion:
Find the largest authorized Bosch automotive retailer in your area and enquire about how to order these parts.
A shop that deals with refurbishing Bosch distributors must have access to the parts.
These holding springs are probably interchangeable and used on other models.
Pelican may have a lead, call PP and ask directly.
I see that PP sells the gear, gear-pin and vacuum advance.

Anyone: Let us know what supplier you may find for parts that PP doesn't sell.

BTW: I use a Zip tie around the springs so they can't accidentally come off the cap.

[Walter_Middie]

Kurt and Gunter,

I just went through this with my distributor. Last thing before I installed my engine, and I broke my distributor spring putting the cap back on. I couldn't find the springs anywhere, so I ended up getting an old Bosch distributor from a wrecking yard. The clips were the same. It was off a fairly modern VW car - if that helps.

[SCWDP911]

sub'd for future reference

[holtjv]

I'm going to be doing this job this weekend, or maybe next.

I was getting only 20 degrees total advance so I at first suspected the vacuum hose/advance unit. The hose was indeed hosed, but with a new one and sucking on it, I could affect the idle. So I'm suspecting the mechanical advance.

Can I assume that in the end game, both mechanical and vacuum advance are created equal? I adjusted the dizzy to get 30 degrees TA over the weekend.

Anyway, if anyone's interested, I'll let you know how it goes. I know the thing is dirty.

Jack

[Gunter]

If both vac and mech advance work properly, the total advance is around 33 deg with ~5-7 deg at idle.
The internal springs and weights are usually good but the mech advance mechanism (Slide-plates) can be very rusted or gummed up. Clean and lube thoroughly.

Also, the top half of the shaft (With the felt plug) is the actual mech advance transfered from the weights and moves seperately; clean and lube.
I use penetrating oil first, and engine oil after.

After assembly, put a short hose on the vac advance and suck. It should move freely between stops.

[holtjv]

Thanks. I'm at about 7-10 degrees at idle, which is where it was when I bought the car about 1.5 years ago--runs much better in general.

I'll go through the distributor Saturday and report.

Jack

[304065]

Originally Posted by Gunter

Remove the circlip on the shaft the easy way: With circlip pliers, not like some Barbarians who use 2 small screwdrivers and either destroy the circlip or have it fly into space.

Barbarian here. Does your circlip actually have eyes on it that can engage a pair of circlip pliers? The clips in my '65, '66 and '71 distributors are just a circle of spring steel wire. Can you post a photo of this clip and the pliers you use?

It took me three hours to get it out the first time. Keine bier.

[Gunter]

Originally Posted by john_cramer

Barbarian here. Does your circlip actually have eyes on it that can engage a pair of circlip pliers? The clips in my '65, '66 and '71 distributors are just a circle of spring steel wire. Can you post a photo of this clip and the pliers you use?

It took me three hours to get it out the first time. Kein bier.

Yes, the SC distributors have eyes on it for the circlip pliers.
The post stated right on the top that the procedure is for an '82 distributor.
No idea what the earlier version uses.
Sounds like 2 very small screwdrivers are the way. (Watch it fly!)
I suggest getting circlips of the right size with eyes from an industrial supplier and external circlip pliers. (They'll know what kind/size you'll need, bring the shaft along)

(A trip thru the tunnel and over to 'Joisy and a bier after)

[holtjv]

here's a link to some photos--will post directly later. j

http://picasaweb.google.com/holtjv/SCDistributorService?authkey=yANGthSUdok

[holtjv]

I completed the Gunter distro rehab on my 79 SC today with the following input/comments/advice to add:

1.***Ensure the little metal dowel is in place in the shaft groove. Mine was not, and upon installation the timer core (the metal piece that looks like a spider) and shaft would turn independently. I figured it out after pulling the distro out, then putting in, over and over b/c the car ran like crap. Didn't help my mentality that I had just changed the ignition wires, even though I did start it after I replaced them and it ran fine.

2. It was worth the effort. Although it really was not very dirty, just the disassembly and re-lubing of everything increased my mechanical advance by 3-5%.

3. Not sure what the drift (punch) was needed for

3.5 The hex screws were very tight and I needed to use some pb blaster on them to get them loose.

3.6 The timer core was very tight also, and needed some pb blaster

4. As stated before circlip pliers, or snap ring pliers, are essential for the job.

5. Good chance to clean the housing, too.

6. Here are my advance #'s, if anyone's interested:
a. Idle: 6 degrees
b. 2k: 17
c. 3k: 20 (max mechanical)
d. 4k: 25 (with vacuum connected)

Prior to this rehab job, I was at 15 degrees at idle and maxing, with vacuum, at 30 degrees. These numbers are by recollection but I think they're right. Although I lowered the advance a bit (15 to 6 at idle), you can see that I'm getting an additional 14 degrees mechanical and 5 more on vacuum, which I hear is about right for my car. The vacuum was working the same before/after.

For the pre-refurb numbers, I was getting an additional 15 degrees total compared to 19.

So I'm happy! And thanks to Gunter for inspiring me to do the little job and helping with it. It's a little intimidating but as long as you don't lose the little metal dowel, which just pops out when you pull the timer core out, you'll be good.

Jack

some pics, with one additional to the web album posted above:

[holtjv]

One more, the completed distributor:

[Gunter]

Originally Posted by holtjv

I completed the Gunter distro rehab on my 79 SC today with the following input/comments/advice to add:

1.***Ensure the little metal dowel is in place in the shaft groove. Mine was not, and upon installation the timer core (the metal piece that looks like a spider) and shaft would turn independently. I figured it out after pulling the distro out, then putting in, over and over b/c the car ran like crap. Didn't help my mentality that I had just changed the ignition wires, even though I did start it after I replaced them and it ran fine.

2. It was worth the effort. Although it really was not very dirty, just the disassembly and re-lubing of everything increased my mechanical advance by 3-5%.

3. Not sure what the drift (punch) was needed for

3.5 The hex screws were very tight and I needed to use some pb blaster on them to get them loose.

3.6 The timer core was very tight also, and needed some pb blaster

4. As stated before circlip pliers, or snap ring pliers, are essential for the job.

5. Good chance to clean the housing, too.

6. Here are my advance #'s, if anyone's interested:
a. Idle: 6 degrees
b. 2k: 17
c. 3k: 20 (max mechanical)
d. 4k: 25 (with vacuum connected)

Prior to this rehab job, I was at 15 degrees at idle and maxing, with vacuum, at 30 degrees. These numbers are by recollection but I think they're right. Although I lowered the advance a bit (15 to 6 at idle), you can see that I'm getting an additional 14 degrees mechanical and 5 more on vacuum, which I hear is about right for my car. The vacuum was working the same before/after.

For the pre-refurb numbers, I was getting an additional 15 degrees total compared to 19.

So I'm happy! And thanks to Gunter for inspiring me to do the little job and helping with it. It's a little intimidating but as long as you don't lose the little metal dowel, which just pops out when you pull the timer core out, you'll be good.

Feels good, eh?

Yes, the little dowel is the joker here.
I suggest for anyone doing this to print out the instructions.
The small drift is used to tap down the timer core (Star wheel) AFTER the small dowel is placed in the groove.

Cheers.

[patkeefe]

As I just yanked my 78 SC distributor apart, this is great to find this post.
Two questions:
Is there a benefit to replacing the magnetic pickup coil (the ones Warren linked to)?
I would like to limit my total advance by 3 degrees less (or so; turbo). Can I simply find a bit stouter spring somewhere?
Thanks!
Pat

[rootmatt]

Originally Posted by patkeefe

I would like to limit my total advance by 3 degrees less (or so; turbo). Can I simply find a bit stouter spring somewhere?
Thanks!
Pat

I doubt it. A stronger spring will only delay the full advance until higher rpm. In order to reduce the total advance, you will need to mechanically restrict the range of movement of whichever advance mechanism you wish to affect. (vacuum or centrifugal)

[Gunter]

Originally Posted by patkeefe

As I just yanked my 78 SC distributor apart, this is great to find this post.
Two questions:
Is there a benefit to replacing the magnetic pickup coil (the ones Warren linked to)?
I would like to limit my total advance by 3 degrees less (or so; turbo). Can I simply find a bit stouter spring somewhere?
Thanks!
Pat

If the coil worked before, why replace it?
Is your '78 a regular US-SC?
What do you mean by: Turbo?
The stops determine total advance.
Steve Weiner could tell you how he fixes the stops when he recurves a distributor to run on centrifugal only.
What is your total advance with vacuum disconnected?
Meaning from Z1 to??
My '78 US distributor only shows a total of 30 deg at ~6K.

[JBO]

How often should this be done? I installed a rebuilt distr. about 7k miles (2 yrs) ago and presume this would be like a once every 10 yrs/60k miles thing.