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MG MGB Technical - condensors

hi all, has anyone had bad problems with condensors. iv used 2 in 7 mths the last one lasting 300 miles. are they pretty much useless now or could i have a problem. is electronic ignition the way to go and if so which one.
many thanks bob.
1970 ish bgt.
Bob Taylor

Bob - It appears that present day replacement capacitors (condensers) are in the same class as brake light switches - crappy. Since they are relatively cheap, you could keep cycling new ones through until you find one that will last. Perhaps a better approach is to stick the old one (if you still have it) back in. Capacitors will generally fail shortly after installation and if the old was working, it will probably outlast you. Finally, when replacing points in a distributor, look at the contacts and see if there is a great deal of metal transfer from one contact th the other (big pit on one contact and a batching mountain of material on the other). If there is no indication of excessive metal transfer, leave the old capacitor in place, it is doing its job and is still good. Cheers - Dave
David DuBois

Condensors [Capacators ] have a fineite life. They are a major cause of circuit board problems. Also because everything is built to a price, you get what you pay for [hopefully ] At any electronic parts store, componants are usually available in diferent grades. Just ask for a top of the line condenser, they are only a few dollars. I can't remember the micro farad figure to ask for. Too many grey hairs !
S Sherry

Don't go to an electronic parts store for a distributor condenser. They may well have the correct value (.18uF to .24uF i.e. .20uF or .22uF preferred value) but are unlikely to have any with the correct mounting tab and terminations. I've never had a condenser fail in 40 years, including cars owned up to 20 years and 80k miles. Having said that like many electrical parts *modern* stuff can be poor quality, so don't be tempted to change your condenser just for the sake of it. If it ain't broke, don't fix it.
Paul Hunt

I have a 75 with a 45D4 Dizzy. Last season I must have gone through 4 condensers in 600 miles. Through process of elimination, I found that the condensers themselves were not the problem, but that the black lead (that gets fed through the hole in the dizzy) was getting pulled loose from the crimped connection. My problem was first that they are cheaply made, and second that I had it running straight out of the distributor, instead of leaving a little slack in the dizzy.

While I'm still having some distributor problems (I think my vacuum advance is crapped out amongst other things) I THINK I solved my condenser problem.

Hope this helped.

CRH Hoebel

IMHO, yes, pertronix is a good idea. It eliminates both the points AND the condensor. On the midget and Sprite pages, bad condensors have shown up often enough as the cause of starnge running problems that they are a running joke (Your hood ripped? Must be the condensor!). If you do go with a Pertronix kind of solution, please be sure that the ground (earth) braid in the distributor is clean and functional, as the Pertronix units do not supply a ground path and electronics take a dim view of "iffy" grounds like you get when the braid is dead and ground is being supplied via the mechanical advance.
David "just don't forget to lube the distributor shaft occasionally" Lieb
David Lieb

Bob. I had a few problems with the ignition side of my 78 GT.I fitted Lumenition magnetronic ignition it seems to have made the engine smoother. I can push the choke in sooner.You could give electronic ignition a try.Dennis.
Dennis Day

I had a condenser failure about 20 years ago. I experienced sputtering and backfiring when there was even slight load on the engine, although it ran fine at idle. I found the points to be very dirty, so I cleaned them, and the engine ran perfect again. But only for a few miles. Then it began to sputter and worsen with load. I was on my way to a friends cottage at the time and was half way into the 60 mile trip. Between getting there and back, I must have cleaned those points 8 times. Once I got home, I got a new condenser and the problem was solved. Now that I think of it, I think the points and condenser were quite new, and I changed out the condenser for the old one, which worked fine until 5 years ago when I switched to the Pertronix. The Pertronix system is easy to fit, and I also find the engine to be super smooth at idle. I keep the old points and condenser on a spare dizzy in the boot (along with a test light to set the static timing) in case of sudden Pertronix failure.
Erick Vesterback

I am trying to restore a 78mgb. The price was right(free) and i got what i paid for, a lot of work. My first of many questions is Where does the low tension lead go on a 45D4 distributor. Any and all help is greatly appreciated.

A 45D4 should have a single wire coming out of the side of the body of the distributor with a male spade on the end. This is part of the condenser and has a quick-fit connector part way along which fits to the one-part points assembly. There should be a single black/white with a female spade coming of a spur on the main harness between the coil and the alternator which joins to the wire coming out of the distributor. That goes back to the coil -ve terminal, where there should be two black/white wires in a single spade. The other wire goes back to the tachometer.
Paul Hunt

Bosch (at least here in OZ) supply points,caps rotors and condensers for the 25D and 45D Lucas and they are of good quality. I buy mine from Super Cheap Auto.

This thread was discussed between 20/04/2009 and 06/05/2009

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