Ignition condenser poll

This is intended as a little effort to help us all to get the right condenser, and is inspired by the recent post about another one bad out of the box. Anyone who posts here with any frequency is aware of the problem. Lets see if we have a consensus of what works. I haven't bought one in years because of the three tractors that run frequently, one has EI, and two others are diesel.

What brand has worked well for you? lets see if we can find a consensus.

I see a lot of "bad condenser" posting but never a why! As I just stated in this post, the device is "two conductors separated by a
dielectric"...definition of a capacitor/condenser...like in condensing or smoothing out something rough...like ignition spikes occurring when
the ignition coil attempts to keep primary current flowing when the points open, thus "attempting" to stop it and in doing so produces the
high voltage secondary pulse to fire the plug. Is soothes this spike to keep it low and slow enough to not arc the points when opening.

You take one or two pieces of plastic sprayed with aluminum (in today's market) oiled impregnated paper with aluminum foil sandwitched
(in the old days) of sufficient spacing and area to get the required storage/voltage stand-off required. You attach one "plate to one wire
and the other to the other wire which is usually welded to the case. Roll it up, stick it in the case, put a cap on it glass seal the cap and you
have your product. Funny, in all the Motors Manuals, Chilton, I and T, OEM published literature, I have never seen a value nor voltage
breakdown rating of the points condenser. So I have no idea as to what it's supposed to be.....

So in failing out of the box is it shorted or open? If shorted or open, did it get inspected after assembly? NO! Either condition and if it
were out of tolerance for capacitance value would be detected and the component rejected. If shorted your points could be replaced with
a piece of wire and your ignition fuse would blow. If open your points wear out prematurely.

Other possibilities are the wrong value. If the value is wrong your timing (dwell) wouldn't match your engine spec per your service manual.
Anybody try different numbers? When I ran gas I used to turn the dist CW till the engine started limping, turn it CCW likewise and set it in
the center. Ran for years, cars, trucks, tractors....

That's my take on the subject.

Failing out of the box is one thing.
In recent years, I have had what I thought was high condenser failure rate.
Then I thought a little more about it. I didn't have any idea how old the condensers were. Maybe some were 10-40 years old. When these tractors were in full use, regular tune-ups were performed. At each tune-up, the condenser was replace as a standard practice. If the condenser was replaced as part of an annual tune-up, they never had the opportunity to fail.

I see a lot of unverified posts about "bad"ignition capacitors. I rarely see any real facts posted. Capacitors are rated by MFD. Either
they are correct or they are not. If they go bad - they can be shorted to case - or lack capacitance. I have had very few problems with
new capacitors over the past 40 years. I think in 40 years, I got one bad one and that was OEM in a Tecumseh box.

Repeating something over and over does not add to the argument. How about some real facts?

I haven't had one fail in a few years because I quit replacing them with new ones after several new ones failed. The ones I had fail did not fail completely. The tractor would start and run normally for a few minutes then would start to miss and lose power until the tractor hardly had enough power to move itself. If I turned it off for say 10 minutes then started it again it would run normally again for about the same time or a little less before repeating the same symptoms. In each case, replacing the new one with the old one fixed the problem. All the ones I had fail were 12 volt distributor machines but that is probably all I was working on at the time.

I don't buy enough condensers any more to have any bad experiences to relay.

The only thing left with points is the TO35. They have been there for years, haven't give trouble, so I leave well enough alone! But when they do fail, it will get converted to electronic.

My opinion on the bad condenser theory though is, the demand is so low now that there is not enough money in making them to invest in producing a quality product and still have a profit margin.

Most likely they are coming from foreign producers, using salvage equipment, with the cheapest material that can be found, by novice, minimally paid employees.

This leaves the retailers little choice, sell what they can get and take a chance on a lot of returns, or just don't sell them.



While on the subject, I found this, supposedly a quote from a Delco Remy document. It's third hand info, but has some interesting thoughts to ponder...

"Burning of points results from high voltage, presence of oil or other material at the points, defective condenser or too small a gap in the points. High voltage can be caused from high voltage setting of the regulator or high resistance in the charging circuit or the third brush set too high. On third brush generators too small a gap at the points allows the points to stay closed longer resulting in the average current being high enough to allow the points to burn rapidly.

Contact pitting results from an out of balance condition in the system which causes the transfer of tungsten from one point to the other so that a tip builds up on one point and a pit on the other. The direction in which the tungsten is transferred gives an indication for correcting the situation. If the tungsten transfers from the negative to the positive point one or two corrections may be made. Increase the capacity of the condenser, shorten the condenser lead, separate high and low tension leads between the coil and distributor, move these leads closer to the engine block. If the transfer is from the positive to negative point, reduce condenser capacity, move low and high leads closer together and/or away from the engine block, or lengthen condenser lead.

Good luck with your trouble shooting. This information was taken from a Delco Remy electrical equipment book.

Borrowed from Alan Hale's web site. Now you know how to fine tune your condenser for longest point life."

What brand of condensers are you guys buying? I've never had a
bad one in the last ten years. I'm guessing I buy at least 20
condensers a year. I buy from Carquest,A&I, and Adam Herschel.

(quoted from post at 08:53:24 04/27/18) I see a lot of unverified posts about "bad"ignition capacitors. I rarely see any real facts posted. Capacitors are rated by MFD. Either
they are correct or they are not. If they go bad - they can be shorted to case - or lack capacitance. I have had very few problems with
new capacitors over the past 40 years. I think in 40 years, I got one bad one and that was OEM in a Tecumseh box.

Repeating something over and over does not add to the argument. How about some real facts?

Click to expand...

eeing as how most folks do not have a failure analysis laboratory available to them, we do not see any info of exactly what/how in the condenser failed. Most of the time (if the condenser actually failed vs 'I touched all sorts of connections & things in changing the condenser & don't have a clue what was really wrong') it will be a short or intermittent short (temperature). I say this because many, not all, engines will run without any condenser at all (but weak spark) which is like an open condenser, but none will run with a shorted condenser (like points welded closed). As to wrong value, I claim that not running due to wrong value is almost a big "never", because I have personally tried values from 0.01uF in increments, up to over 55uF(generator noise suppression cap) and still have a running engine, Typical ignition condenser value is about 0.2uF. Note that I didn't say points won't pit with wrong value, just that engine will usually run.

I usually go with the better napa's or just pick one up at Deere. None bad out of the box but longevity is no where near what it used to be. The points you get now a
day's aren't any better.

Seems some claim there is no high failure rate. In reality all a condensor is is a capacitor. You can no longer buy a quality capacitor made in the States. Years ago the
dud capacitors came from south of the border. Now a day's they are the better ones and the duds come from the land of almost right. If you really want to know capacitor
failure rates walk up to any hvac guy and ask how many are on his truck. Condensors are no different.

There is very little difference in microfarads of the condensors in these old tractors. As far as testing one it's about the same as any other capacitor. A meter will
tell you for sure if it's shorted or getting weak. It will not tell you for sure it will work. Big difference.

Nobody needs high-tech equipment to test a cap. A $3 multimeter can test for a short, and/or if there is capacitance. That is all you need
to know if trying to diagnose a "no-run" situation. A capacitance meter can tell you if the cap you have is in the correct MFD range.
Again, not exactly high-tech. If a cap it out or range, the engine will still start and run.

My mag and distributor book gives me the MFD ratings of the correct caps for most applications. I have yet to get a new one that was off.
New old stock OEM caps that have been on some shelf for 60 years, yes.

(quoted from post at 11:30:02 04/27/18) I usually go with the better napa's or just pick one up at Deere. None bad out of the box but longevity is no where near what it used to be. The points you get now a
day's aren't any better.

Seems some claim there is no high failure rate. In reality all a condensor is is a capacitor. You can no longer buy a quality capacitor made in the States. Years ago the
dud capacitors came from south of the border. Now a day's they are the better ones and the duds come from the land of almost right. If you really want to know capacitor
failure rates walk up to any hvac guy and ask how many are on his truck. Condensors are no different.

There is very little difference in microfarads of the condensors in these old tractors. As far as testing one it's about the same as any other capacitor. A meter will
tell you for sure if it's shorted or getting weak. It will not tell you for sure it will work. Big difference.

Click to expand...

he HVAC motor start & run capacitors are doing a very different task than an ignition condenser. Those carry 10's of ampreres of current all day long and over 100 amperes during starting, whereas the ignition condenser carries about 4 amperes for milliseconds at each break. That is why the physical size is so different even though you may be comparing equal uF size capacitors....the HVAC motor caps must be able to dissipate the heat resulting from those continuous high currents.
Other topic: reason a meter fails in some cases to be a reliable condenser tester is that is does not detect voltage breakdown since it 'tests' with a very low voltage, whereas the ignition condenser sees 200+ volts on ever point opening.

"Burning of points results from high voltage, presence of oil or other material at the points......"

That release from Delco Remy is interesting to me for one reason.
Back when about every tune up involved replacing the condenser (capacitor), I seem to remember that Delco Remy's condensers didn't appear to be sealed too well, or at least it looked like moisture would be able to get inside the condenser where the wire went into the end cap. I always used to use Echlin, available from NAPA, and they had a rubber boot on the end to keep moisture and oil out.
I always like to adjust the GM points on the fly, though, with the GM products having the window on the cap. With Ford, you sometimes had to make several efforts. I always adjusted them with a dwell meter, not a feeler gauge.

What interested me was how sensitive the systems were, moving wires closer together, near and far from the block, changing the length of the condenser wire... Never heard any of that before!

I have heard back in the day, that condensers were available with different mfd ratings, but never knew of anyone actually going to the trouble. I know if I had asked for that at the auto supply they would have laughed me out the door!

I do like the rubber boot on the condenser. Not sure if it is there to keep moisture out, or as a vibration grommet, or both.

I was told in my high school auto mechanics class that the condenser needs to be matched to the coil, and never change it unless you sure
it's bad. The only one I ever had fail was on a small outboard, as soon as it warmed up it would cut out on one cylinder.

A multimeter with a cap checker may not always tell you one is good when hot or under higher voltage, but it will prove one is open or shorted. I only had one test good that wasn't under load in 35 years of testing them on elevator equipment.

(quoted from post at 11:20:50 04/27/18) I was told in my high school auto mechanics class that the condenser needs to be matched to the coil, and never change it unless you sure
it's bad. The only one I ever had fail was on a small outboard, as soon as it warmed up it would cut out on one cylinder.

Click to expand...

In desperation to get my Yamaha 125 running again, I grabbed a used condensor that had been removed from a 3020 John Deere. I had to add some length to the lead on that condensor, but then it fit the Yamaha just fine. The Yamaha started up and ran just fine for several more years with that John Deere condensor.

That was about 45 years ago.