Clever condenser test

[abowie]

Silver car developed a bad miss and a case of the "not runs" today. I had been reading one of the MG forums and a clever chap from Cumbria called Andy Tilney had posted this:

"What you need is one of these,i made my first one when I was an apprentice nearly 50 years ago, just clip it to earth, and the cable to the CB on the coil, (- for negative earth cars, + for positive earth cars) you don't even to remove your distributor cap, its the quickest way I know to check a condenser,A.T"

I used it and it correctly diagnosed a dead condenser. Connected, the car ran perfectly. Disconnect the earth clip and runs terribly. You do get a bit of a shock through the condenser when clipping it to earth but it sure beats replacing the damn thing, only to find that it wasn't the problem in the first place.

[1954Etype]

Sometimes the obvious is the most difficult to see! Brilliant!

[abowie]

How does this work? Does it just put the second condenser in parallel with the one in the distributor?

[abowie]

Further sage advice:

"andy tilney, Cumbria, United Kingdom
Its best to connect it up first then try to start it, you are right you can get a bit of a shock from them when they are charged up, we used to charge them up on the spark plug cleaning machine, then shout to someone and throw it at them, so they would catch it, we used to make all sorts of things for testing stuff. Another good one was a cyl leak tester which we made using a spark plug, a hydrolastic suspension valve, and a tyre pressure gauge, it works just as well as my snap on one I use today, AT"

[PeterCrespin]

How does this work? Does it just put the second condenser in parallel with the one in the distributor?

Yes, basically. Nothing to stop you running external quick-change capacitors like on some competition machines.

I remember an old Triumph I had that used twin external caps because it got very crowded with twin individually-timed points, as opposed to twin fixed points where the capacitors sat inside as normal. Lots of 60s-70s bikes even used a slightly larger cap instead of a battery - kickstart only of course - which saved weight and acid spills if you dropped the bike, especially off road.

[Duckham]

Brilliant!

Agreed - why didn't I think of that?
My condenser failed last year and I replaced it at the roadside with the brand new one from the spares box in the boot.
THAT one misfired badly but got me back home where I replaced it with another new one which also misfired. Finally the 4th one worked.....
This idea would have saved a lot of swearing!
Joe

[Heuer]

Unless the one you use for the testing is faulty!

[andrewh]

Excellent so very simple but valuable. Presumably its a get y home tool as well

[JagWaugh]

This, and a long wire with an inline fuseholder and 1/4" spade terminals, and a selection of fuses, battery clamp, alligator clips, bullet and spade gender changers for either end are get home tools in the same category as tyraps and duck tape.

The problem with the fused wire is that you have to replace it nearly every time you go on a rally, as there is almost always somebody who goes home with it!

The problem with the condensor is getting a test cap that is actually good - last month I put a new one into a dizzy and put it on the distributor tester... the cap only lasted long enough for me to set the dwell, it was already shot by the time I started to test the mechanical advance.

Andrew

[Duckham]

Unless the one you use for the testing is faulty!

True, but I've learned my lesson(s):
1. Take the working one out of the dizzy and keep that as the spare.
2. Keep a fistful of additional ones in the car as extra spares.
and now 3. make up the test rig asap and check it works before putting in the boot. !
Joe