VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 All of a sudden no spark

JD,

Can you explain what is inside a condensor that actually "leaks"? Is it something that the eye can see or is it only detectable with an instrument? I have seen coils leak oil. Is it something like that?

Is it a problem more prevalent in condensors manufactured in ancient times and solved by more modern manufacturing processes? If the problem has been solved by more recent manufacturing processes, finding a more recently made one would be tha answer because it's pretty easy to adapt a condensor intended for one application into another application. In fact it may be a drop in substitution like the 1-piece Delco point set that I found drops right into the ancient distributors.

Is a condensor that tests bad guaranteed to actually affect engine performance?

I ask this for 2 reasons. The first is personal experience of never having a condensor fail. The second is that there can be some tiny performance differnce between a just out of the box electrical component and one that has been used a tiny bit. An example of that can be seen on the Bonneville salt flats.

The wind there generally blows from west to east. So,to set a record a vehicle has to run up the course (downwind) and back (upwind) within a 1 hour period. If a 1 way run qualifies for a return run to set a record, before making the return run spark plugs run for only a few miles are often replaced with new ones, because it may take only a fraction of a MPH to set a record and supposedly new plugs can provide a tiny edge over slightly used ones. That difference, while supposedly real, would never be felt in ordinary driving.

When I first started racing Bultaco off road motorcycles on the Southern California desert in the 1960s they still had point ignitions, as did the other race bikes (Husky, Greeves, CZ, Maico, KTM, etc, etc). Being an inquisitive youngster then I asked a lot of questions about maintenance, 2-stroke jetting, suspension modification, etc. What I was told about ignition maintenance was to check the point gap after each race because the Spanish Femsa points had rubbing blocks that wore quickly affecting point gap and, thus, timing also but to not worry about the condensor as they seemed to last forever.

I still have 2 of those ancient Bultacos, restored now, and the spark is so hot that even turning the magneto flywheel by hand produces a blue spark. It's like turning an electronic ignition distributor shaft by hand to bench test the electronic components and getting a spsrk, truly amazing.

First a condenser usually fails when hot.
Considering the price of a condenser it is more practicle to replace it rather than test it.

Condensers are usually two long strips of aluminum foil about an inch wide sandwiched between layers of waxed paper, rolled up and placed in a metal case. One plate is connected to the case and the other to a lead wire that goes to the distributor points.

A condenser stores electric power just like a battery. When it can no longer store power (a small amount of continuous current is flowing)the condenser is considered to be "leaking". If there is any leaking at all the condenser should be replaced. Old condensers can also lose their capacitance, which means they no longer have their correct microfarad value.

I have never had a condenser fail on a car either, but since they do have a "shelf life" I test each condenser before it is installed. Many of us have heard in the past about someone installing a new condenser on a distributor and found that there was no spark only to learn that the new condenser was defective.

Condensers can be tested with an Ohm meter or with a regular condenser tester, so I always suggest testing a condenser before it is installed if the car owner has the means to test a condenser. If neither piece of equipment is available then a new condenser can be installed without testing it first.

JD,

Thanks so much for explaining that. One of my sons is an electrical engineer. Next time he comes to visit I'll ask him to bring whatever instrument he uses to test what he calls capacitors and show me how to use it.

I still have a few NOS Bultaco condensors made in the 1960s. It will be interesting to see how they test.

In the meantime I'm going to Goggle "How to test a condensor".

Thanks again!

There is no shortage of instructions on condensor testing. Here's one: mgaguru.com/mgtech/ignition/ig129.htm

Some of the tests are on "ohms" scale there should be no circuit and as a result the capacitance will be severely reduced or non existant.
Tony

Here's one for you. I had a problem 20 years ago in a 50 chevy. Every time I made a left turn the engine would cut-out; die dead as a door nail. I would wait a minute and the car would start and run perfectly until I made another left turn and then it would die again. Right turns didn't matter just the lefts. After a week of checking, testing, and head scratching I finally discovered the ignition coil had leaked some of the oil (probably PCB,s) and when I made a left turn the oil would slosh to the outside and the coil would short internally. Sitting flat it worked and tested fine. Now I wish I put it in my trophy case instead of throwing the darn thing away

So has anyone truly figured this out. I am very intrigued and interested least to say.

The problem in diagnosing an electrical problem is several different failures can cause a given situation. For example loss of spark at the plugs can be due to faulty: condenser, points, ignition switch, coil, wire connection, etc. Determining which one can seem to be like a dog chasing its tail. The process helps to stave off dementia.