Distributor Shaft Play

[DienstXIV]

Hi Everyone,

I decided to upgrade my ignition system to the ignitor II pointless ignition. When I removed the rotor from the distributor shaft I noticed that I can move the shaft up about a quarter inch to a half inch. Is the shaft supposed to have that much play in it? My engine has been having idling problems and I was wondering if this could contribute to it. Also my tachometer is very bouncy so maybe this could be the reason?

Thanks in advance!

Cheers,
Alex

[smadsen]

What car?

Your '75 probably has a Bakelite plastic spacer down near the drive gear that notoriously crumbles over time and the pieces can be found in the bottom of the case if you remove the oil drain plate. Use a pair of popsicle sticks to retrieve the pieces.

Meanwhile, every time you rev the motor the distributor shaft jumps up and slide-hammers the bushing that locates the shaft. Also, your timing is moving around a bit as the bevel gears change contact patch (I think).

Long & short, eventually you have an inopportune, catastrophic distributor failure when the bushing dislodges and the shaft/rotor thrashes around inside the cap. It's not a roadside fix then.

The fix is a distributor rebuild and a group of stainless steel shims to keep the shaft from jumping up & down.

I'm just relating my experience with an '82 SC. YMMV.

[fanaudical]

Distributor shaft play may not be THE reason, but it is a contributing reason. I would certainly address it.

[brighton911]

Smaden is right on, best address this ASAP. PartsKlassic carries the distributor rebuild parts you will need.

[Paulporsche]

I have read (possibly on this forum) that the max allowable play is only about 1.5 mm, and that the amount of play that you have can cause an uneven idle. I have also read that axial play has less of an effect on a Pertronix system than a points one. Note that neither of these statements has been verified by me.

Mine has about 2 mm play w/o any issues that I can see.

As discussed in your other thread, there can be other reasons for this, incl a too lean mixture, vac leaks and other ignition parts.

[kach22i]

I'm trying to remember but mine only pulls up about 1/8", and 1/2" is far too much.

I looked into distributor rebuilding a while ago, but with the car running so good I never pulled the trigger.

2010 Thread:
Dizzy refresh - Barry Hershon's contact info?
Dizzy refresh - Barry Hershon's contact info?

[DienstXIV]

Okay everyone, it seems to me like my distributor is the last problem to all my rough running issues. I installed the Ignitor II electronic ignition this morning and the car wouldn't fire. I noticed that when fully seated the black piece with the magnets that mounts onto the distributor shaft is way lower than the red piece that replaces the points. I moved it up a bit and the engine fired with no more bouncy RPM gauge and the engine seemed to idle with no fluctuation but misfired like the timing isn't adjusted correctly which I will do later. I got the car running as a test but this is not the solution.

Main thing is, the play in the distributor shaft needs to be addressed and I would like to rebuild it myself. Does anyone know of a write up of how to do it? Partsklassic has a kit for my car but I would have no idea how to install all the new parts. I'm pretty sure I need to add some shims to move the distributor shaft up to the correct position and get rid of the play.

Lastly does anyone have any recommendations for a timing light that has long power leads and can measure after top dead center? The one I have from Harbor Freight can only measure before top dead center and has really short leads.

Cheers,
Alex

[HaroldMHedge]

I recently posted rebuild information for later distributors which also applies to earlier ones as well.

From 3.2 Distributor post #17.

Originally Posted by HaroldMHedge

When rebuilding my 3.2L ignition distributor I used 2 VW Distributor Repair Kits 12118630239 - Bosch 1237010007. You need two kits for the fiber/phenolic shims (1/kit).

P****k*****k has a kit with bronze shims which replace the fiber/phenolic shims.

I'm not sure where to get the Oilite bushings if needed for the housing.

Search the Pelican Parts for rebuilding the distributor and you will find all the information needed to rebuild your distributor. Here are several of the better threads.
Distributor Tune Up - Repair
Distributor service (Clean and lube) real easy without removing the pinion gear!
83 sc distributor Has TSB 78-04 Distributor Changes and really good information on gear removal/installation and shim placement. Yes, it discusses earlier distributors but it's still applicable.
distributor lube... Bosch distributor lube is difficult to find but Lubricam Distributor Points Lube seems to be a good substitute.

[porsche930dude]

this should help
https://forums.pelicanparts.com/porsche-911-technical-forum/333640-distributor-service-clean-lube-real-easy-without-removing-pinion-gear.html

[fanaudical]

You'll need to remove the pinion gear to address the bushings.

Distributor rebuild info

[Paulporsche]

Alex,

Can you compare positions of the top of the red and black portions of the ignitor? Now that you have made the change are they equal, is one still higher or lower than the other, and by how much? Can you upload a pic to illustrate this?
Thanks.

[DienstXIV]

Hi Everyone,

Just wanted to write a quick update. After much consideration I decided to replace my old distributor with a 123Ignition completely adjustable distributor. I put it in this weekend and pretty much all of my rough running is now gone! When the engine is warmed up the car idles dead on at 950rpms. No more rough idle and no more bouncy tach. I feel like I can tune the distributor a little bit more to get a little extra pep down low but the power delivery is fairly smooth and makes the car so much easier to take out for a spin! I feel confident that I can even throw the keys to my girlfriend and she would be able to drive the thing to the store!

Cheers!
Alex

[Oregon 911]

Hello all.
Here’s a company I found on the Internet that I’m going to send my Porsche Bosch distributor to to have it rebuilt. Advanced distributors 17495 Marystown Rd.
Shakopee, MN. 55379
(612) 804-5543.
They said they could rebuild the Bosch distributor for Porsches.
Advanceddistributors.com