I strongly recommend that you check the curve in situ with a strobe light at various RPM's.
Start with the basic 5 deg BTDC ~900 RPM. Then connect the vacuum. There should be no change but as soon as you come off idle, the advance should be noticable.
Record the degrees for all RPM's right up to 6000 were it ends at ~30-33 deg.
Let us know what you get.

Yes, I will post results when I get the engine back in the car.

Great thread, Gunter. Thanks for posting this information.

I cleaned and re-lubed the distributor on my SC project cabriolet yesterday. My distributor was in a similar situation to Pat Keefe's -- on removal I found that I could barely turn the thing! It amazes me how far out of whack things can get and the engine would still run. Between the condition of the distributor and the monkeyed-with CIS (probably because the distributor was overlooked as a cause of starting/driveability issues), I may be more than halfway home to getting project cab back in fine fettle.

One different thing I did: Rather than pry the timer core with screwdrivers to remove it, I used (carefully) one of those cheap battery terminal pullers with a small block between the puller screw and the top of the distributor shaft. As Gunter said, be watchful of the tiny pin that locates/mounts the timer core in its correct position!

It was unbelievable how dirty/sticky everything was in there. After copious cleaning and lubing, it looks great and ready to go for another 100,000 miles. Also as Gunter said, use the dust cover. This distributor didn't have it and I'm thinking that was a major contributor to its horrible condition.

These distributors are expensive to replace -- take good care of the ones you have. :)

Brian

when i unplug my vacume lines and plug to check the timing the idle jumps to 1500 so i cant check the timing without them connected. Anybody know what the problem could be? its an 82 sc right now its at 5 degrees with the lines connected. I havnt done the distributor service yet

Sounds like the lines are crossed.
Check the vac connections at the throttle body: Advance is connected in the REAR of the TB, the retard goes in front of the TB.
Timing is set with vacuum disconnected: 5 deg BTDC at ~900 RPM.
Along with that, you need to adjust the mixture and idle.
I suggest that you do the cleaning/oiling of the distributor and also make sure that the vacuum diaphragm works by sucking on the advance line and watching the movement inside. (Cap off)
Who knows where your timing is at the moment, something is screwy.
Service the distributor.
Then you'll know what shape the weights/springs are in and that the parts move freely.

I appear to have two different sizes of springs on my advance weights is that normal? I cant get in there though because two of the three mpg allen screws are stripped out. Looks like i hit a dead end on my rehash. Im not too keen on ez outing them but it looks like thats the only option. Any bright ideas?

also how much movement is the vacume advance arm suposed to have? It holds vacume fine but the arm doesnt move at all when you blow or suck on it is that bad?

The vacuum advance plate was frozen on my distributor on my '83 cab before I rebuilt it. Penetrating oil and slowly turning it back and forth freed it up. FYI, the three screws on mine were the slotted type and not allens.

Brian

how free is free? Seems like it should have to move about a half inch?

That's about right. You'll see how it operates if you can get yours disassembled.

Brian

Yes, two different springs are used. The lighter spring provides the rapid ramp off-idle, and the heavy spring provides the gentle, slow ramp after 2500 rpm engine speed.

The vacuum advance limit is determined by the internal stop.
Make sure the vac advance plate pivots freely in the magnetic pulse generator, use penetrating oil.
Now that the pod is off, test the vac diaphragm by sucking on the line connected to the advance nipple.
It moves just a little but the important issue is that it holds the vacuum and doesn't leak.
As for the broken Allen screws, I suggest that you go to a machine shop to have them drilled out on a milling machine. If you attempt this yourself, the drill will wander off into the softer Alu material; not good.
Unless you have the right equipment and skill to do it, you'll ruin the distributor body and you'll be sorry.
I believe the thread is M4 but if all fails, it can be drilled/tapped to a sligthly larger SAE - NF size thread.
Leave it in the hands of a good machinist.

Early_S said it about the springs/weights.

Thanks guys! Iv got it all back together i think the problem lies elsewhere. I feel bad asking all these questions in someonelses thread but here goes. As gunter said to check the vacume lines. They seem to be in the right places advance in the back and retard at the front lower and the wur goes to the upper larger port. But the suctive power is questionable. The reason the idle rises when the lines are disconnected is beacuse the retard has alot of suction at idle and the advance doesnt. Then when its reved the retard vacume drops and the advance sucks under load and when reved up which seems normal but.... is it? Should they suck equally at idle?

You say: The reason the idle rises when the lines are disconnected is because the retard has a lot of suction at idle....................
How can you have suction if the lines are disconnected?
Be more specific and refer to the OEM vacuum connections.
Do you still have the Thermo-time valve in the loop?
Pictures would really help to show how your lines are connected.
Timing is set with vacuum DISCONNECTED at 5 deg BTDC @ ~900 RPM.
Are you doing that?
Set the timing first according to factory specs, then connect the vacuum.
Even with the lines connected at idle, there should be no change in RPM.
What max advance does your strobe light show at WOT?

I made a new thread here http://forums.pelicanparts.com/porsche-911-technical-forum/379208-82sc-vacume-timing-problem.html#post3607237

Has anyone diagrammed all the washers? I had them laid out nicely and in order during disassembly, but did not pay attention to the magnetic effect of the pick-up and got them jumbled...the diagram does not clearly show how many and where...

Thanks-
Matt

Bump for help for Early_S_Man. I figured anyone who has posted in here will get an email response via subscription, and many do not know of Warrens plight...

Just did this particular project this weekend. The timer core was damn-near welded on and it took an overnight penetrating oil soak and the battery terminal puller (great tip BTW, couple of screwdrivers had NO effect on this puppy). Interior of distributor was all bunged up with some sort of reddish oily junk and the advance weights were reluctant to move. Cleaned and freed it all up and stuck it back together again using the thinnest smear of antiseize on the part of the shaft the timer core sits on since I may want to get it off again sometime in the future. That fiddly little pin is a pain to work with since the core magnetizes any steel anywhere near it. Finally used a pair of wooden tweezers and a brass drift to get it in place. A tip for people haveing trouble getting a philips driver to properly engage the 3 bolts that hold the coil in place: a #1 Robertson (green square tip) screwdriver does a great job on these little bolts.

My distro had no washers in it but has about 1.3mm axial play. Should I try to take this out?

I am not too concerned about axial play; the wear marks on the gear should be in the middle.
If you like, mark the gear and take it off with a little puller, then use fiber or brass/copper washers to reduce the play.
I am surprised about the 3 small bolts being Phillips or Roberts.
If they are Phillips, I don't see how a Roberts screwdriver would work and vice-versa.
Various SC distributors I took apart always had small Allen bolts for a 3mm key.

I guess the bolts are just another example of the stuff that can happen in a 25 year old car :) Probably someone had some metric philips along the way. BTW I beleive a true Philips head (as opposed to something like a Reed & Prince head,also cruciform) has a center squarish bit (thus the ability of the Robertson to engage) and the arms of the cruciform radiate out from the points of the square. It also tends to be shallower than a comparable R&P and has a flattened bottom to the hole.

Thanks for the comment on the axial play. The wear pattern was in the middle so I guess its OK. Besides I just got back from a mid winter gotta-test-to-see-if-it-works run and it was too much fun to immobilize the car again :)

"metric [P]hilips"

??? Is there such a thing? I thought the Phillips head screwdriver spec. was set, and independent of Metric vs. SAE...

Metric threaded with a Phillips head I'd think. Probably some bolts sitting around a shop somewhere when whoever it was stripped out or lost the Allen headed bolts.

Does anyone know if there's a resistance measurement for the coil section, and what the proper end play should be, for the shaft? Working with parts from a box. Thanks in advance.

Distributor gear marking
 

I keep reading where one is supposed to mark the distributor gear before removing it from the shaft.

What is the net effect if it the gear is reinstalled 180 degrees out from where it was originally?

I think the hole for the pin is off center and the gear can only be installed one way. Not true; correction:
Revised: I looked at my '82 SC distributor and the pin-hole looks centered.
Since it has an even number of 12 teeth, it shouldn't matter if the gear is installed 180deg off.
Generally, it's good common practise to mark before dismantling anything. :)

Awesomely bad running b/c the timing will be so far off. It won't be hard to tell, believe me.


hth.

Jack

Distributor gear marking
 

Do you mean spitting, popping, and the best you can get the timing down to is 40 degrees advanced at 3500 RPM's?

I think the question regards the gear, not the entire distributor.
I don't think the gear being 180 out matters, BTW, unless the pin hole is indeed offset. I don't recall any offset in my SC distributor.
Pat

I looked at my '82 SC distributor and the pin-hole looks centered.
Since it has an even number of 12 teeth, it shouldn't matter if the gear is installed 180deg off.
Generally, it's good common practise to mark before dismantling anything. :)

SRT356/911:
It sounds to me that your distributor is installed with 1 tooth off?
Pull it out and rotate 1 tooth before pushing back into the worm-gear on the crankshaft and try again.
Other reasons for the timing being off that much is:
The worm-gear on the crank was installed the wrong way around during rebuild and:
The green wire from the distributor to the CDI module got the wrong polarity when splicing.

Distributor gear marking
 

Jerry Woods had gone through my 78SC distributor and reset the curve. We had a long chat about gears and what the engine was doing.

Bottom line is Jerry was correct about the gear and causes of the bad running. Gear can go which ever way, makes no difference. Distributor fires after the tab clears the mark.

I took off the Nology wires, made new plug wires from scratch using some old Bosch connectors that checked out, gapped the plugs down to .025 and it runs like a top. All missing gone and I was able to set the timing right where Jerry said

I had installed an MSD 6Al CD unit. And that is what they like when it comes to running well. Nology wires work well when you are running stock components. MSD units do not work well with Nology wires.

Thanks all.

Gunter,

Thanks. Good write up. Used it, cleaned it installed it.

Two remarks:

When you said take care of the very small dowel pin you ofcourse meant the VERY VERY VERY small dowel pin.

I had no luck in finding the SST Nobeer. Must only be available in the US:D

Michel

Gunter,

Great write up. At a moderately careful pace I was able to complete the cleaning in about 3 hours. Your directions were perfect. Thanks a ton!

My dizzy was pretty nasty. Here are a couple of pics - before and after.

The dark area is dirt ... not poor lighting. It was really caked on.
http://forums.pelicanparts.com/uploa...1231871700.jpg

http://forums.pelicanparts.com/uploa...1231871712.jpg

Regarding the functionality of the dizzy, I noticed that the weights can only move so far before they reach a stopping point. Is this what governs max advance for distributors? If not, what does?

Thanks again,
Craig

Jeez..that dizzy really needed a cleaning. Mine was not nearly so dirty.

Regarding the (very) small metal dowel--be careful not to lube it or the shaft groove. It slipped out of place on my dizzy and left me stranded. It took me a week of hunt and replace diagnosis before Jamie Novak gave me the idea to look at the diz.

Well crap ... I oiled mine. But I don't see how the dowel could come out as long as it is seated properly. Maybe if one of the circlips came off and let the timer core rise enough for the dowel to fall out.

I don't know how mine came out, honestly, unless it just wasn't seated well to begin with, which is possible.

I took it apart and wiped it down and not had a problem since. It could also be that mine was worn a bit more than yours thus looser in the groove.

Craig:
Feels good, eh? :)

Using oil for assembly is o.k.
The very small dowel is held in place because of a tight fit plus the washer/circlip prevents it from coming out.

The expansion-limit for the weights is normal.
You may have noticed that the weights actuate the upper half of the shaft.
Thats the mechanical advance.
Very important to lube the upper half with a few drops of oil under the small felt.

Now you can check the curve.
Mark the pulley every 5-6 mm with white paint, then get the Stobelight ready.
Have someone rev at various RPM like 2k, 3k, 4k, 5k while you note the degrees first with vacuum and then without.

Let me know what you find. :)

Hi guys. Very interesting thread. I wish I found this years before it would have spared me the issue I have now. My 81-930 idle started intermittently bouncing. Checking final uncovered the dizzy had play in the top bushing. It is possible to shim it in someway rather than punching out the old bushing and pressing in a new one? Here in Japan finding such parts are next to impossible so where can I order such a bushing? or shim?

Thanks
Rob

Rob--did you take it apart to see exactly what's worn or broken? You may just have something loose...J

There is no bushing, the housing is the bore.
How much play do you have?
More than 0.002"?
Take it apart.
Remove the gear from the shaft.
Inspect the weights and springs.
If they're good, leave the in place.
Take the housing and shaft to a machine shop and explain what you need.
Ask them to make a bushing with an I.D. for the shaft and an O.D. for the housing.
They'll bore out the housing and press-fit the new bushing observing the needed dimensions so the contact surface of the bushing is in the same place as the old one.
Re-assemble and enjoy. :)

When I tried to disassemble mine ('79 US model), I was unable to remove the pulse generator and coil because the timer core (star wheel) was too tight on the shaft. I tried to use a variety of pullers to remove the wheel, but had to quit when I started to mangle it. Anyone else have this problem? And yes, all retention hardware had been removed at that point...;)

Question: Does anyone one know what the correct spec callout is for the gap between the star wheel and the stator towers? I searched, but couldn't find it anywhere.

Mike...:cool: