General Tech Temporary Condenser Install

It's common practice if you have a ignition failure on the road to swap on your spare coil and see if that resolves it. I just bungee it next to the mounted coil and move the wires over.

Now I wonder if you can do a similar quick-fix / test if you suspect a failed condenser?

Specifically - connect the condenser lead to the CB post on the coil and ground the condenser body.

If the condenser inside the distributor has failed, would this work around it?

If the condenser inside the distributor has not failed what would be the result?

Sure, it's not a lot of bother to try a replacement condenser on the TR distributor (just don't drop the screw!) but I'm thinking of this for my other British car where distributor work involves kneeling, crawling over a tire and working in an area that is pretty hot if the engine has been running.

Thanks for any theories or advice. If need be I can always just try it, but thought I'd check here first.

Seems like most times if the failed condenser is still in the circuit doubling up would not help. Might be some EE reasons why even two perfectly good condensers in the circuit would not work, but I leave that to an EE.
Bob

Depends on how the condenser failed. If it went totally open-circuit, then adding one at the coil should work fine. I believe some VWs were even configured this way from the factory.

However, if the condenser has become "leaky" or shorted, then it will have to be disconnected.

What I don't know is what happens if the original condenser has only lost part of its capacitance. My guess is that the engine will still run well enough, possibly even with no noticeable difference. One of my books talks about examining the points to determine if the capacitance is too high or too low, by whether metal is being transferred to the fixed contact, or away from it. (I forget which way is which offhand.) Barney Gaylord comments that likely anything up to 0.6 mfd will work, while stock is less than 0.3; so two of them should be OK.

I don't know which of these modes is most common with ignition condensers, as I'm not in the habit of testing them after I know they are bad. But all three modes are common in other circuits.

Why not try it and see? If nothing else, it would be easy enough to just cut the wire into the old condenser, and still add one to the coil. Certainly much easier than fumbling around with the nut, washer and tiny screw on the side of the road (and taking a chance on losing them).

The other alternative of course is to just carry a loaded distributor in the center of the spare tire. It makes a handy place to store the other components

Yeah - I got to thinking more about it and realized that a leaking condenser would probably introduce a partial ground that would rob some or all of the spark.

Still, I experimented -

I added the external condenser with the current (good) condenser still in place. Engine ran fine.

I undid the internal condenser and connected the external condenser and the engine ran fine.

Of course to confirm what I expected, I started the engine with both condensers undone and it ran fine.

Problem is 1) 'ran fine' was in the garage - the real test would be on the road and over many miles and 2) I don't have a failed condenser handy to mess with.

TR3driver said:

... If nothing else, it would be easy enough to just cut the wire into the old condenser, and still add one to the coil. Certainly much easier than fumbling around with the nut, washer and tiny screw on the side of the road (and taking a chance on losing them).

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I think that is the best alternative for the car with the hard-to-get at distributor.

TR3driver said:

... The other alternative of course is to just carry a loaded distributor in the center of the spare tire. It makes a handy place to store the other components

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Indeed - that is what I do for the TRs...

Geo Hahn said:

Of course to confirm what I expected, I started the engine with both condensers undone and it ran fine.

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Man, I sure wish I had thought of that! Long time ago, I didn't carry spares with me, and the engine just died going up a hill. Figured it had to be the condenser, so I walked up over the hill to a filling station to buy one. By the time I got back, the local police had towed the car away! (Something I said must've made him mad, no way was I blocking traffic nor was there any traffic to block.)

Lest anyone wonders - I say it 'ran fine' but I expect if run very long like that the points would suffer badly -- but yes, it would have gotten you over the hill.

Back in the Sixties in high school my auto shop teacher was more of EE than auto shop guy. Anyways he spent a lot of time on ignition stuff with points perhaps because most cars ran that way back then. He maintained that the condenser worked with coil and not the points since what the condenser did was absorb static electrons and the points made and broke the circuit, and if we put a new condenser on each time we replaced the points we were wasting money and inviting trouble. He further showed how we could tell by which side of the points the pit and tit were on established a problem with the coil or condenser, but I am over the hill and cannot remember which side showed what. I would think you could have as many condensers as you wanted in the system, but if one shorted or grounded or what every they do when they go defective would shut done the system, but like Randall suggested you should be able to cut the one outside off or the one inside and be back running. I am surprised the Geo car ran without a condenser, even at an idle because I was told that it will not run without one, but again maybe if you gave it some gas it would crap out.

sp53 said:

...I was told that it will not run without one, but again maybe if you gave it some gas it would crap out.

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I expect that, although it seemed to run okay, that I was getting a weaker spark at the plugs and a big spark at the points. Not the combination one wants.

Further testing sounds like a job for "The Visible Distributor':