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Bad Condensers...

Posted: Mon Jul 07, 2014 10:31 am
by Heidi Frances
Hi All,

I was leaving Sat morning for a C&C event and while in the driveway, as I was putting down the top, the car stumbled and then died. I tried to re-start and it stumbled and then would only fire occasionally (maybe one out of four). I have just done a lot of fuel work and replaced the spark plugs recently so those were top on my mind. It was acting a lot like I had forgotten to turn on the fuel (never done that before :wink: )... I managed to flood the car a bit thinking it wasn't getting gas which didn't help, but after about a 10 min rest it started and ran long enough to get the car back in the garage. I took a different car to the event and started in when I got home. That gave me a bit of time to think... I have seen this before - this being the third time actually. The car will run on 3-4 cylinders up to about 2Krpm and then spit and sputter and backfire badly any faster than that. It is the strangest thing, but it was/is a bad condenser. I pulled the distributor and replaced the condenser with a a new one I just got that looks like all the others I have installed and the car is running perfectly now. Here's the thing: The one that was in there had maybe 200 miles on it. I did a tune up in May which included points and condenser.

When I picked up the car four years ago it wouldn't start because of a bad condenser. Then a couple years ago, I had the car die on the way to an event and it was the condenser. I have taken to replacing it at every tune up (once a year) and this one failed within a couple months... All the parts have been new "Bosch" from one of our vendors. I just don't get it... It is just a capacitor... Are there any known conditions that will cause the electrical system to eat them? Is anyone else having the same issues? Is it just crappy Bosch parts? I keep a brand new one in the toolkit and it is fairly quick to swap out, but...

My car is a stock '58 Normal.

Thanks,

Franny

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 11:11 am
by Dave Wildrick
In your situation, I would be tempted to install the 123 ignition, which has no condensor.

I have had one condensor die while I was tuning the car, but only that one time.

I also had a Bosch blue 6V coil die once while I was adjusting the carbs, and it took a while to figure out that the spark was extremely weak and insufficient to fire the ignition (standard distributor).

I wonder if you might have a weird spark coil, although I have no idea if that could cause your problem. You could swap it out just for grins and see what happens.

Also, is it possible that there is another ground path for the condensor that you are not seeing that is shorting it out, like missing insulation somewhere at the distributor connection?

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 11:23 am
by Heidi Frances
Thanks Dave,

All the insulators are there on the post/points mount on the distributor, but that is a good point. I will take another look. It is easy to have part of it turn as you are locking down the points, but I'm pretty careful to monitor that. The coil is older, but still throws a nice blue spark and the car runs great (with the new condenser). It is blue (painted black). The points are mildly pitted after a season - not bad. I think we put about 2-3K miles on in a season. The distributor was rebuilt by Ab T a few years back and seems to be working just fine. I'm a bit of a stickler for keeping it stock in its operation :).

How often do you swap out your condenser? Do you do it at every tune up or just when it causes you problem (not very often it sounds like)?

Thanks for your help,

Franny

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 11:25 am
by Ron LaDow
Fran,
Maybe it's physical rather than electrical. I think those things use paper for the dielectric; could the clamp on your distributor be deformed such that it 'dents' the can?

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 11:30 am
by Heidi Frances
Thanks Ron,

I wondered that too, but it really isn't that tight... It is the original clamp and is tight enough for it not to move, but not much more. I'll run the caliper around the one I just took out to be sure.

I think you are right - standard electrolytic cap.

f

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 11:31 am
by Dave Wildrick
Franny Brodigan wrote:Thanks Dave,

All the insulators are there on the post/points mount on the distributor, but that is a good point. I will take another look. It is easy to have part of it turn as you are locking down the points, but I'm pretty careful to monitor that. The coil is older, but still throws a nice blue spark and the car runs great (with the new condenser). It is blue (painted black). The points are mildly pitted after a season - not bad. I think we put about 2-3K miles on in a season. The distributor was rebuilt by Ab T a few years back and seems to be working just fine. I'm a bit of a stickler for keeping it stock in its operation :).

How often do you swap out your condenser? Do you do it at every tune up or just when it causes you problem (not very often it sounds like)?

Thanks for your help,

Franny
I only replace the condensor if it acts up, which as you say, is not very often. I have a standard distributor on my 64C coupe and the 123 ignition on the 65C coupe.

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 12:13 pm
by Jacques Lefriant
Hi
I have not seen many condensor/capcitor failures. premature point erosion is caused by the wrong value of the capacitance. You can buy an inexpensive digital VOM(meter) that will measure capacitance. If you convert to a Pertonix like hall effect trigger for the coil you can eliminate the condensor.
j

Bad Condensors...

Posted: Mon Jul 07, 2014 12:22 pm
by Tom Wavrin
Condenser quality had been discussed in the past with the following quote from Brad Ripley:
"The condenser is a capacitor which stores electrical energy. They have a limited service life. The condensers we get from Bosch now are made in Brazil and probably are not very high quality. So it may be worth it to check a new one before installing on your distributor. I know Ab rejected many I sent him for his distributor rebuilding." I remember someone saying that Bosch also contracts their manufacture in Turkey, possibly to supply Europe, and that the batch quality control was poor.
Per a posting by Curt Crowell, I believe, the condenser capacitance should be in the range of 0.27 - 0.32 microfarads. He mentioned that a capacitance meter can be purchased on-line for about $20.
I would really like to try running a BR18 modified with the 123 ignition system but that's a lot of points and condensers that work well most of the time.
Tom

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 1:04 pm
by Heidi Frances
The last condenser that went bad was made in Turkey. I do have a capacitance check on my VOM so I can give that a try, but I bet dollars to doughnuts, it would read the correct value. It fails after a minute of use... As Ron said it is probably a breakdown of the dialectic allowing the plates to short. ...or maybe the connection to the plate(s) has failed.

Thanks Tom for the history... I guess if you have a good one, leave it in, but carry a spare (or two). I wanted to get a feel if this was just me or if others are having the same issues...

Thanks,

f

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 1:13 pm
by Jacques Lefriant
Are we saying that the adage to replace the condensor with a new one since they are cheap did not take into account the the poor present quality. By now all the paper ones have been replaced so my advice: if it checks in the ballpark leave it.
j

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 4:13 pm
by Bruce Smith
Two signs of a bad condenser can be difficult starting and poor radio reception (static) when the car is running. A bad condenser won’t have the ability to store a charge and cannot control the size of the spark. Although starting will be difficult, it should still be possible. As Tom points out, a good capacitor should measure 0.27 - 0.32 microfarads. Some condensers for VW will be slightly lower but can work fine. I think condenser failure is less common than we believe. I’ve been through about 100 BR18/022 rebuilds and tested just one bad condenser. Condensers dating back to the 1960s can still be good. My ‘63B has the original BR18 with the condenser (below) date coded 8S (August 1961) and still working fine! They are pretty simple components and I’d expect even those of lesser quality to have a lifetime longer than you’re seeing, Franny. Especially if testing OK when new. If your condensers are indeed going bad and it isn’t a shorting/insulation problem, verifying the output of your coil is probably a good idea.

Bruce
http://www.sparkingplugs.com

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 5:26 pm
by Geoff Fleming
More likely a bad coil than condenser. When the condenser fails, ( kind of rare), it usually won't allow a re-start, while a bad coil may work in the lower rpm ranges and than start to give the engine a 'running out of gas' feel, as it lags in output. The coils can work well until warm and then start to sputter out. My experience with a bad condenser was a complete non start until changed. Of course if it is simply a loose bracket where the condenser is clamped to the distributor or a wiring dis-connect, the problem is easily solved.

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 5:56 pm
by Jon Schmid
A third sign of a bad condenser is to have your engine quit like with a kill switch, at a stop light. Luckily these cars are light enough to push to the side of the road.

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 6:13 pm
by Heidi Frances
Well, the car runs great with a new condenser... The spark out of the coil is nice and blue. I drove the car over the weekend about 20 miles and at 75-80mph at times so nice and warm. No difference with temp - never skipped a beat! Next time it goes out, I can swap in a new coil I have in the tool kit as a backup, but it seems weird that if the coil was going bad, it would fry the condenser and then be just fine until it fried the next one... I had a couple go on my Beetles too. Usually shortly after a tune-up. I'd put the old one in and I was good to go.

Would a bad coil respond to a new condenser or be able to fry one?

I wonder if I can get the bad one apart...

f

Re: Bad Condensers...

Posted: Mon Jul 07, 2014 6:39 pm
by Bruce Smith
Franny -

Let me know if you're interested in having your coil tested, both initial spark and at break-down (operating temp). It's pretty quick with a coil tester and I can send it back to you the next day.

- Bruce