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LUCAS CONDENSER FAILURES

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angelfj1

angelfj1

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We have been having a ball driving the Grey Lady and put about 1000 miles on the clock. However, as of this past weekend, we have now had four condensers fail. Here's an account of the first failure which prevented us from enjoying the breakfast run at the TRA meet in North Carolina.
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<span style="font-weight: bold">Duryea Day - Boyertown, PA Saturday - September 1, 2012</span>
<span style="font-style: italic">"TRA has a long tradition of conducting a breakfast run on Saturday morning of the meet. We were running the car up the mountain roads to the show field on Friday and noticed a misfire. We only had 25 miles on the car before we left for the show, and we had not yet established any history on the carburetor or ignition tuning. After the show, the car ran great for about ten minutes and then the miss came back. After inspecting the float bowls and swapping distributor caps, rotors, and wires, to no avail, we watched the breakfast run depart past us and our spirits sank. Reasoning that the condenser was the next logical substitution, we dove into our “spares department” tote bin and brought the car back to life with the next push of the starter switch."</span>

After returning home we have experienced three more condenser failures. The circumstances seem to be consistent. Start out, engine cold, runs great, smooth idle. Engine warms up, approx. 180F still OK. Get into a bit of traffic, usually stop light and as engine approaches approx. 2/3 full scale on the temp gauge, the engine begins to stumble. If I try to accelerate, the engines misfires and at times will backfire. After these incidents I have pulled off the road and gone for a coffee whilst the engine cools down. If the temp goes below half scale, about 180F the engine will start up and run nicely. Upon heating up a little the cycle repeats.

We have conducted all of the usual checks and have ruled out timing and carb settings. Colour Tune looks ideal. The plugs are a bit sooty and we have considered going to the next highest heat range. But when we replace the condenser with a new one, the engine runs well regardless of temp. This fix does not last long though and eventually the condenser completely craps out, usually a few days later.. Considering that condensers are most difficult to test, we have reached this conclusion based on a process of elimination. At least one time a new condenser did not cure the problem and we could only conclude that it was dead out of the (green and white) box.

So, perhaps you can offer your experience and suggestions. I hear that better condensers are available. Does anyone know of a source?

Except for poor quality, is there anything else that may be causing these condensers to fail?

Cheers,

Frank
 
Frank - is it possible that the *coil* is failing?

When you stop to change the condenser, the engine - and coil - cool off.

Just a thought.

Tom
PS - GREAT looking car!
 
What he said.
 
Frank,

There were (are?) some poor quality condensers on the market. About four years ago I had two new ones go bad within a few hundred miles. I changed to Standard Motor Products LU206 and had no problems. You can get them on Amazon.

But four seems like a lot. Are they from the same manufacturer? Like Tom said it might be something else. Maybe the heat getting to a cheap batch.

Jeff

74.5 & 75 TR6
 
Just reading about the wonders of The Blue Coil...
 
I'd lean towards the failing coil theory, too! In all honesty, I've almost given up on changing condensors, but it is a possibility. Like so many current replacement parts, they just don't seem to make most ignition system bits like they used to! :frown:
 
X5 (or whatever) on the failing coil cooling down while you futz with the condensor.

Easy to test -- strap your spare coil next to the one that's mounted (I use little bungees) and when the engine dies immediately swap the 3 wires over to the 2nd coil. If it starts right up... Walla!
 
A bad condensor will fry the points. If your points are still good, you need to look elswhere.

X6 on the coil!

John
 
CJD said:
A bad condensor will fry the points. If your points are still good, you need to look elswhere.
Click to expand...

Good point.

Some of the replacement condensors are horrible quality. I was initially very skeptical about these reports of frequent condensor failures until I got my hands on a few and dissected them. Pretty scary. I wrote this up for the BCF Wiki, under General Technical Articles.
 
dklawson said:
Steve... no link to your thread on condenser disections?

Steve's Condenser Thread from the Spridget Forum
Click to expand...

Thanks Doug and Steve.

Yesterday I pulled the plugs (Champion L87YC) and as expected they were carbon loaded and sooty - replaced them with a new set of same. I have a set of L92YC in reserve and we may move to this higher heat range eventually. The engine started instantly with the new plugs despite having the original coil with new condenser (Lucas green & white box). So with fresh plugs, suspicious coil and new condenser went out and put 30 miles on the clock. I could NOT duplicate the ignition related miss/backfire. Even pulled off the road and let her idle for 15 minutes until the temp rose to 2/3 scale - no misfire. So, I'll leave things alone for now but run with a spare coil, points, condenser, wires, rotor and cap in the boot.

BTW, I did order a couple rotors and high performance condensers from Martin Jay, aka Distributor Doctor.
See: https://www.distributordoctor.com/
When these arrive I'll install them and report my experience.

Cheers, Frank
 
Frank,
I can only imagine your frustration. I had a very similar problem and it about drove me crazy. Everytime the car heated up the engine would mis-fire, and eventually wouldn't run until it cooled off. The problem turned out not to be any of the electrical components after all. As you have, I changed every component and disassembled the distributor numerous times. The problem turned out to be the small screw that holds the condenser to the point plate was slightly longer than it should have been and when the body heated up, it/something changed dimensions (ever so slighly) so that the end of the screw interfered with the advance movement of the plate underneath throwing off the timing. I ground the screw off a bit and never had the problem again. Not sure if this is your problem but thought I'd throw it out there. Go figure. Good luck. Patrick
 
Yes I hear you Frank I am real believer in spark plug examination. Whenever my tr3 acts up, I usually look at them first. I would like to suggest that you make sure the choke returns upon starting when cold. Especially, because your engine is new and not broke in. You do not want extra fuel running down the cylinder walls. I typically after a new engine starts, and warms up just a little, reach up under the carbs and push the jet to make sure it went up.
 
PKPoole,

Recently I had trouble with my condenser (a new one recently installed). The little screw you wrote about somehow came loose and fell out (into the distributor). The ungrounded condenser caused my engine to miss, etc., etc., until I found the trouble and replaced the screw.

I asked Jeff at Advanced Distributors about this and he said I could find the proper screw at any hardware store, but that I should be careful to make sure the screw wasn't so long that it would rub against the distributor base plate. If it were too long, he said, I could use a little lock washer on top to shorten the portion sticking out beneath. That is what I did and solved two problems: (1) made sure the screw wouldn't come loose again, and (2) shorten the part of the screw extending below the points plate.

BTW: After three tries, I found the old screw wedged beside one of the distributor weights.
 
Hello Ed,
I was pretty sure I wasn't the only, or first, guy this has happened to. For me, I noticed how long the screw was after I pulled the entire distributor plate out of the body and just happened to see the screw coming very close to the lower plate (this after numerous disassemblies/reassemblies/parts replacements). For most of us "experienced mechanics" (i.e. old guys), our experience comes from learning from our mistakes (many). Pat
 
Hello, Pat,

I, too (an old guy but not an "experienced mechanic"), am learning from my mistakes and hope that the mistakes I make are not too serious. Fortunately, for guys like me who are pretty ignorant of these matters or who make mistakes, this forum lets us learn from the mistakes and experience of others. A great help!

There's one thing I didn't mention about my experience with the condenser and that might be of help to some others: When there is trouble with a condenser, I am told, after a while the points can suffer (i.e. get pitted or "burn out"). When I realized that my condenser was not grounded, I checked the points and found no damage at all, which leads me to think that the condenser "malfunction" (wire not screwed down) had been taking place for only a reasonably short time.

It is sobering to think that the loss of one little screw can bring the car to a halt.... I am reminded of the poem about "For want of a shoe the rider was lost."

For want of a screw the condenser was lost;
For want of a condenser the points were lost;
For want of the points the car was lost;
For want of the car the driver was lost.
 
CJD said:
A bad condensor will fry the points. If your points are still good, you need to look elswhere.
Click to expand...

I'll disagree, to some extent. It takes a fair amount of running time for a bad condenser to damage the points (due to excess arcing). If the problem has only persisted for a few hundred miles or less, the extra point damage may not be enough to notice.

Ed, if it's any consolation, I had the same loose screw problem last year. I was lucky though, and caught it before it came out entirely. It was just causing an occasional misfire, but we were lining up for a club run through the mountains so I thought I had best check it out. (Actually I went in there with the intention of changing the condenser and checking the point gap, until I found the loose screw.)
 
Randall,


That's exactly what happened to me. On a long road trip, as I was returning home, the car began to misfire. I found the problem when I returned home (misfiring all the way home).

Because the misfiring occurred only on the way home, and because the points were in fine shape, I concluded that the problem with the condenser was just hours old.

I recalled that someone had told me, or I had read somewhere, that damage to the points would not occur immediately but after a fair number of miles. Your statement that it would take a few hundred miles before damage was noticeable confirms what I was told or read.

My MAIN concern when all of this happened was the missing screw. A screw bouncing around free inside the distributor can do some real damage. Fortunately, I found it on the third try (wedged beside one of the weights).
 
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