How do I spot a bad distributor?

[Guest Anonymous]

How much up and down play is acceptable?

What is the normal failure look like in the distributor?

[Guest Anonymous]

Chris,

I really don't know what the acceptable play is but on a prior 1974 2002 I owned,( middle 1980's) one of the signs was going through points like crazy. I was at a local BMW dealer getting a tune up kit and two of the service techs. ( Heinz and Ludwig)came out and looked at the distributor, Heinz told me my distributor was bad, said I would be just going through points, he mentioned way too much play. New distributor back then was $110.00 and what a differnce it made,

Tim

'74 2002

'69 2000

[Guest Anonymous]

When I changed to the 320i injection, we swapped distributers w/ the head. Got everything set up, running well, then it failed smog. We would set it up on a 4 gas, take it to the referee station, then it would fail. After 2 trips back we swapped the distrib again. That was it. There was just enough side to side play that the enginge would mis-fire once. That was enough to send raw fuel out the exhaust and fail the smog check. Of course, a CAT would burn that off but we just had a stock 02 exhaust.

So, the BAD distrib would have been fine on a car that wasn't being smogged. Probably never would have been noticed. It ran fine, there was just a miss every once in a while.

[Guest Anonymous]

I would think that you would see the timming going all over the place, but I don't know.

Michael

72 tii (Bacchus)

[Guest Anonymous]

I will be accelerating and it will just surge with more power than it usually has.

[Guest Anonymous]

Up and down play is not too important. Normal is maybe 1/16", just guessing. Back and forth play is what is important. Basically, if you can move the shaft enough to change the point gap, it's got too much wear. What this does is change the dwell which changes timing. You can emlinate this problem by putting in a breakerless ignition system such as a Pertronix. It is triggered magnetically and does not depend on the cams of the shaft to open and close the points. With this system, the points are eliminated.

[Guest Anonymous]

if the meeting point of the pickup and the magnet are a moving target with play and it sounds like part of his problem is lean misses on deceleration where the dizzy is no longer getting slammed into the back of its play by centrifugal force. Or I could be way off. (He has a petronix.)

[Guest Anonymous]

I also have a pertronix. If the shaft moves up and down won't that advance/retard the timing since it has the worm gear at the bottom?

[Guest Anonymous]

Where can I buy new springs?

[Guest Anonymous]

j/k

if the rotor hits the cap (and the cap is correct and fits) it's bad

if it eats points, it's bad

if it feels gritty when you turn it by had (out of car) it'll soon be bad if it already isn't.

if the diaphram doesn't hold vaccume it's bad... new diaphram costs as much a distributor.

[Guest Anonymous]

expensive, but eliminates distributor, rotor, points,

coil and adds programmable advance and rev

limiter. Not mine but I drove a 2002 with one,

smooooooth.

Michael

72 tii

[Guest Anonymous]

If I remember correctly, the top portion of the shaft pivots on the lower half and is held by a circlip. The shaft is held in one spot by the rotor pressing against the bottom of the dist cap when all is put together. If it has 1/2" play, this sounds excessive and your circlip may be missing. This clip is under the felt pad in the dist shaft viewed by looking down on top of the dist with cap and rotor removed. Even with this play, it will not affect timing as the shaft that is driven by the camshaft does not move.

[Guest Anonymous]

You must be speaking of the mechanical advance springs. I'm not sure if they are available new but you might check Jack Fahuna or Ireland Engineering to see if they have some.

[Robert Kyle]

I've got a bad miss (checked compression; OK.  havent done leakdown yet), and I'm wondering if it's a bad dizzy.

 

Does this look worn out to you?  The dizzy on my E9, the rotor doesn't move THIS much:

 

 

['76mintgrün'02]

18 minutes ago, Robert Kyle said:

Does this look worn out to you?

 Yes it does.

 

The rotational movement is simply the advance travel, but the side to side movement is a problem.

 

Pertronix helps with that slop.  Points would not work well with that one.