Hi everyone,

Today when driving my 81SC with 170,000 miles across the Bay Bridge, I noticed the car would lunge and hesitate when pressing firmly on the gas. Eventually, I was stuck in stop and go traffic - and the car nearly stalled several times. Needless to say, it idled very roughly.

When I would get the car up to speed, the engine seemed to run pretty smoothly though I felt it lacked power. But this problem was very prevalent when starting from a stop - the car would lunge when starting in first and shifting into second gear. When pressing on the gas in second, the car felt as if it were running on 5 cylinders.

I finally arrived at my destination - popped open the engine lid and heard a new vibrating sound that seemed to come from the distributor. I shut the engine down - let it cool - then took off the distributor cap and rotor. The contacts on the cap were pretty heavily pitted on one side - and the rotor seemed quite worn down. So, clearly I need to replace the cap and rotor - which I will do tomorrow.

This will hopefully solve the problem, but I'm wondering if it will only be a temporary fix. Why were the points so heavily pitted in the first place? I placed the rotor back on the distributor, and if I press down on it, I can only turn it maybe an inch at most in a circular direction with no play. However, I seem to be able to lift up on the shaft that the rotor is attached to - and there seems to be a fair amount of play - is this normal? What can I do to diagnose the cause of the pitted points? After 15k miles, how mUch wear is expected of the cap and rotor?

I am bringing the car in for a 15k service next week - the car has gone about 17k without a servicing (outside of oil & filter or course).

Thanks very much for your help, as always. Help me fix my baby!!!

 

This does not sound good that much play in the distibutor shaft is bad. You need to pull the distibutor and inspect the gear and bushing at the bottom of the shaft.
Sounds like the bottom bushing is worn creating lots of play in the shaft. Careful about driving you do not want to damage the gear inside the case that drives the distributor excess play in the bottom gear can cause damage to the drive gear.

 

There should not be more than a few thou play in the end float. More than this indicates wear in the distributor thrust bushing, the drive pinion and/or drive gear in the engine.

 

Thanks for the tips folks. I put in a new cap and rotor - the problem still persists, though not as severely. The idle is rough and the vibrating sound still resonates from the distributor. I can pull up on the distributor shaft maybe 1/4 inch or so, which is clearly not normal. I think what is happening is the rotation of the distributor/rotor at lower rpm's causes the rotor to lift and pull up on the shaft - which then allows the shaft to spin out of true center - which results in the rotor hitting the cap. So, should I remove the distributor? How difficult is this to do (my very thorough Haynes manual does not seem to cover that too well - I plan on upgrading to the Bentley manual in the very near future) - is the process very involved? Can I remove just the shaft itself?

Also, the tachometer jumps around wildly while the car idles and seems to catch properly around 2400RPM - which makes sense since the tach is electrical and directly tied into the distributor, right?

Thanks again for the help.

 

Dylan,
Hop across to the Pelican Parts BBS, post by 86Ragtop, which has a detailed account of the same problem.
In summary, the distributor rotor was thrusting upwards and feasting on the cap. Yours sounds like exactly the same problem and if it is, you need the thrust clearance fixed, with a new washer somewhere on the rotor or a new distributor.
Ned Monaghan

 

A good Porsche shop, or Bosch service center will be able to inspect your distributor, and rebuild it as required. I would not operate the motor with the distributor in this condition. If you wear out the drive gear inside the crankcase, you will have to open up the motor to replace it.

 

Dylan,
This is what your distributor should NOT look like- whoops seems like I cannot post pic as it is on pelican site uploading system but click on this url or paste to your browser to see thread with pics http://www.pelicanparts.com/ultimate...ML/010377.html

Removal of the dist. is fairly simple 'Just make sure it's pointing approximately to number 1 cylinder(notch on the dist there where the rotor points to), and note that on the crank/pulley, the notches will line up. When you put it back, make sure the rotor and the notch on the dist line up while the notch on the crank and the pulley line up.
Put some duct tape across the rotor taping it to the dist so it doesn't spin too much when you pull it. Then it'll just slip right back in'.
That explaination was by our good friend 'Kurt B'and it worked for me!.
Although this is from a 3.2 hope it helps!.
My problem continued for a month before nailing it so hope this helps you in some way!. Also before you have your old one reworked I know Jonnie Walkers workshop has a spare Dist. available if you need one (at a very reasonable price!)
rgds Ben

[ 07-01-2001: Message edited by: 86ragtop ]

 

Thanks to everyone on the board for helping me through this problem. I finally had to buy a new distributor - plopped it in - and no more problem! Even the sputtering idle problem I posted about earlier was fixed - apparently a fluctuating idle is a sign of worn bushings/bearings/whatever they're called on the distributor - so 2 problems solved!

I was quoted 7-900 bucks for a new distributor. A special thanks to John Walker (I gave him a buzz) for recommending Vertex auto for the new part (www.vertexauto.com)...had it shipped over night...brand new original Bosch product with cap and rotor for 500 bucks.

Thanks everyone!