Annoying intermittent misfire

 Intermittent issue.

For some time now I have been chasing an issue where, after a long run, I would slow to a stop or a roundabout and the engine would start to misfire and stall.

I had checked the carb to ensure it was not leaking fuel.

I checked the plugs and plug leads with no obvious issue.

I checked the voltage on the Pertronix electronic points to make sure that the coil and points were getting the right voltage. I did find an issue here and rewired the ignition system to use a relay to supply full 12v to the Pertronix coil and made it look factory.

I checked the timing and vacuum levels.

The issue was impossible to "make" happen and was intermittent.

I installed an O2 sensor on the exhaust to see what was happening.

When it happened the car would run mega rich and stall but would rev no problem.

Last week the issue happened again and this time with the O2 sensor I could see it want from a slightly lean 15.9 when driving at 100KM/h to 10 and would not move from 10 no matter what I did.

I was able to limp the car home and set about diagnosing the issue.

In talking to my great mate Nev, we determined that the issue must be timing and probably the distributor as this is the only thing I had not changed. Other than going from stock mechanical points to the Pertronix.

I gave the internals a good squirt of WD40 and checked the vacuum advance was working.

We determined that the distributor needed to come out and he would loan me one while I get this original one serviced.

The following are pictures of the distributor when I pulled it out. YUK is all I can say..

On the surface all looks ok.. Right.??

Well no, I pulled the distributor and thought that the base had been broken. It looked that bad!

After a quick wipe, the crud came away to find that all was well at it was just 170,000km of crud!

I then removed the Pertronix to find that vacuum advance plate to be very rough and caked in crud!

This is the underside of the vacuum advance plate.

This is the top of the vacuum advance pate. I was actually able to make it stick while still in the distributor. So I think we have found the problem.

Here is the distributor with out the vacuum advance plate. The liquid in the bottom is just excess WD40. I then cleaned this out.

I ahve reassembled the unit and taken it to Nev who will take it to Performance Ignitions in Nunawading to be rebuilt and adjusted to make better use of modern fuels.

Nev has loaned me a Bosh unit that were used in Australian built Clevelands while mine is repaired.

I could have cleaned it out myself, but figured it is better to get it serviced and retuned.

Looking forward to getting it back.