3.2 Distributor Modification

Nutmeg911 · 08-14-2006, 07:24 PM

Has anybody tried to drill out the bushings in the 3.2 Distributor and drill the housing to install bearings? Is there enough material left to do this?

Nutmeg911 · 08-15-2006, 05:47 AM

Ok, maybe this is why nobody has replied? I have never had my distributor out before, are there bearings in there already or are there bronze bushings in there? I posted this because Rusnak had his distributor go bad and he mentioned bushings not bearings and I was thinking if there are bushings in there then maybe it could be modified at rebuild time with bearings, but if bearings are already in there then this thread is null and void. Can some one confirm this for me?

jmohn · jmohn's Garage

Bushings.

I have no knowledge regarding the efficacy of your proposed modification.

Jerry M
'78 SC

stlrj · 08-15-2006, 08:42 AM

It's not really a wear item. The distributor shaft just spins inside the distributor housing with virtually no load resulting in negligable wear.

You might set your focus on something else, like improving your ignition.

Joe

john walker's workshop · 08-15-2006, 09:08 AM

when the bushings wear out, the mechanical advance setup thrashes about and rattles loudly and the unit fills with black dust that coats the cap and the engine runs poorly. that's the wear issue, not the fact that there's nothing electronic in there to get out of sync.

rusnak · 08-15-2006, 02:06 PM

The other thing that happens when the distributor wears out is that the rotor hogs out the cap. Eventually the rotor blows up, and ignition fails. Fuel keeps going into the motor, and is pumped out into the cat. The cat smokes and gets bright orange. It's really quite inconvenient, and something to avoid at all costs.

I have to disagree with the statement that the distributor bushings are "not a wear item". Your whole car is not a wear item unless you drive it. But turn the key, and all sorts of wear items begin to turn, spin, hum, etc.

Nutmeg, I have to recommend that you take the cap off, and see how much the rotor moves radially and up and down. If there is any perceptible movement at all, I'd strongly advise you to take advantage of the rebuild program at Sebring West on Blackstone Ave. You get new advance springs, the little plastic parts get replaced, new advance arms, new drive gear, and new bushings. Mine came with a new cap and rotor, as well as new inner cap under the rotor. I'd advise you to keep the rubber o-ring from your old distributor in case they put the wrong one on when they send your rebuilt one back to you.

Good luck!

Nutmeg911 · 08-15-2006, 06:59 PM

Rusnak

Looking at your distributor, does it look like there is enough room, after you drilled out the housing, to put a set of sealed bearings in there? Oh, how long was the turn around time for your rebuild through Sebring West.

rusnak · 08-15-2006, 07:19 PM

Hi Nutmeg,

I posted a thread about what happened. I want to try to warn other 3.2 911 owners and 911SC owners, so they can avoid what happened to me.

I went to San Rafael to buy some parts from another PP poster. When I left Fresno the car was running strong, no symptoms of any problems. When I arrived I noticed a noise coming from the distributor. I was out of luck, as there were no places to buy a 3.2 distributor in San Rafael on a Saturday afternoon. As it turns out, you can't buy one anywhere but at Porsche! The only other option is to have your old one rebuilt. Well, I was over 250 miles from home so I decided to try to limp the car home. It gave out about 30 miles on the return trip, and I was left stranded in downtown Oakland off of the 580 freeway.

To make a long story short, I had to buy a new distributor from Porsche (which they sell as a rebuilt unit for $500). You can get the same result by going through the rebuild program for $250. It takes a few weeks to get your old one back, but the shipping is included in the rebuild price. I don't think rebuilding your distributor yourself is a viable option, because you should get new springs, recalibrate the advance mechanism, replace all of the tiny plastic parts, drive gear, etc.

Another potential problem in rebuilding it yourself is what happened to Mysterytrain. His drive gear fell off and ended up going around the crankshaft and holing the case. I don't know why his fell off, but this can happen if you rebuild your old distributor yourself. You have to remove the dowel that holds the drive gear to the distributor shaft with a punch, then drive in a new one. I would have not enough confidence in reusing the old one, and risk a $5000 rebuild. You also can't put any load on the drive shaft and bend it. That thing has to spin at 4-5K rpm.

You can take your old distributor out: crank the motor clockwise until the TDC mark for cyl #1 lines up with the notch in the sheetmetal and the distributor rotor lines up with the notch on the distributor body. Then the 13mm clamp down nut needs to be loosened, and the distributor will pull right out. Installation is reverse of removal. You can get a really good look at all of the stuff that gets replaced in a distributor rebuild. To me it's well worth it, and believe me, you will save money big time compared to calling for a tow, renting a car, or lucking out once in a million like I did, and run into a nice lady who will drive you around downtown Oakland chasing parts for an hour.

Nutmeg911 · 08-15-2006, 07:49 PM

Rusnak

I will definately take advantage of the program, but I'm still entertaining the thought of getting an old distributor, just the housing and the shaft, and seeing if I can modify it to accept sealed bearings, this is a feature the MSD distributors have, unfortunately they don't make one for our cars.

rusnak · 08-16-2006, 11:15 AM

Nutmeg, IanC was talking about someone on this board who was thinking about rebuilding his own. Mysterytrain has some amazing abilities. There is another guy who is a master metal fabricator (he is building his own airplane). Maybe you can approach them with the MSD distributor project. I think of the bearings as a sacrificial bronze material that is meant to wear and allow you to re-use the distributor shaft. One problem will be to get the bearing race to seat well and not spin. You may need to modify the distributor shaft to accept a tapered bearing race, and the engine case to act as a seat. In all, it sounds like a big machining project that is beyond my abilities for sure.

Bill in OKC · 08-16-2006, 11:51 AM

Is there any periodic maintenance required for the distributor? Should the bushing be lubricated somehow? How does it get its lubrication? Thanks!

Early_S_Man · 08-16-2006, 12:06 PM

Bill,

The rotor needs to be pulled off and the felt plug needs to be removed [at least initially, after years of neglect] so 10W, 20W, or 3-in-1 oil can be dripped into the hollow until it won't take any more! Replace felt plug and give it a few drops, too ... then replace rotor. Thereafter, oil the felt every 3 - 4 months, or at every oil change, whichever occurs more often.

john walker's workshop · 08-16-2006, 01:43 PM

how about contact info for sebring west. good info to keep in the little black book.

Nutmeg911 · 08-16-2006, 08:10 PM

Rusnak

I'd be happy to discuss this project with anybody interested, the first thing I need to do is get my hands on a used one, disassemble it, "mic" the shaft and housing and research my bearing choices and go from there. You are right I might have to turn down the shaft to get the correct dimension for the I.D. of the newe bearing, possibly.