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MG TD TF 1500 - Symetrical vs.Asymemtrical

I have a 1950? MGTD 4034, I've toyed with the idea of converting the positive ground dustributor to a Petronix systems. My question how do I diffrenetiate a symetrical vs.asymemtrical cam. I've read some and saw a picture, but like where's Waldo I couldn't see the diffrence anyone have a suggestion or clear picture. As always appreciated
Jon Levine

Jon

Understand your issue with that. Post a picture and we should be able to assist. I have Petronix in my TD, probably going on 10 years. Love it.
Bruce Cunha

Just from personal experience, not technical knowledge, the older cars are generally asymmetrical....have more rounded corners.....
I have a pos. ground system, with pertronix ignition, and bought the wrong one, the first time....
When I got the package, all I had to do was look at the magnetic collar, in the package, and I knew it was the wrong one...Moss took it back and exchanged it.
I had even printed out a photo of the three types, and I still couldn't tell, by looking at the dizzy.
If you post a photo, (as previously suggested),someone will probably be able to tell, for sure.
Edward
E.B. Wesson

Note the position of the slot


Rob Edwards

Rob
I never really noticed that,when I did mine....
It would have saved me some postal costs.
Edward
E.B. Wesson

Jon, see http://www.ttalk.info/Tech/pertronix_igniters.htm for a bit of info on them. I think they're great. Bud
Bud Krueger

IMHO: Petronix is one the best mods you can make to one of these cars...Love mine.
David Sheward

Had my Pertronix 3 years, pos. ground, love it...
Tom Maine (TD8105)

on my way back to n. ill. from coppell, tx. near dallas. 1000 miles each way. taking all 2 lane state and county roads. i love this trip. (standard points and condenser)

regards, tom
tom peterson

There's nothing wrong with the standard ignition, but the Pertronix never needs adjusting, or changing, unless you mess up the wiring....So careful initial setup is critical...Once wired, however, forget it...it will mind itself.
First one that I used, was on my Jag, way back in 1969...
The car was a '67 "E-Type", and every time I turned around the points were closing up....
At that time, Pensky Racing was offering a setup very similar to the Pertronix....Drove the car that way for 10 more years, without touching the dizzy, (except rotor and cap).
Both of my "B's" had it, as well.
Edward
E.B. Wesson

Edward, but why do you touch the rotor and the cap??Greetings, Huib
Huib Bruijstens

Worst and biggest issue with electronic ign = "without touching the dizzy" = never lubed the advance and shaft!

I HATE worn out distributors from this neglect! (but not as much as I hate the people who do it!) And it is virtually impossible to repair them.
Rover 2000TC used 19 degree distributor advance, far more than most cars then, although it became more common with emissions engines, result being much more wear for the same neglect. The local Rover dealer in Pittsburgh did not do the service correctly (at all).
I replaced every single distributor in customer Rovers, which was every single Rover in town eventually, as they all ran like crap when the dizzys wore out, and I was apparently the only person who knew why. The good news was that new Lucas distributors cost $19 then, only twice what points, cond, rotor, cap cost, and you got all those with it. Of course, $19 was a weeks worth of groceries (4 FULL bags) for two hungry guys given to eating roast beef, and the last beef roast I saw in the store that was comparable was $58 a couple of months ago.

Kicker is that the major advantage of Pertronix etc. is that it tolerates sloppy distributors - as it causes them. Other than Rover, my specialty was Jags, and I never had problems with points closing up - that's simple incompetence. My personal cars usually got points etc when I bought the car, and never again for many years, but they got routine lubed every 3000 miles religiously, and cleaned & major lube once a year.

FRM
FR Millmore

Don't know if you're serious or not, but of course I lube the dizzy occasionally....One of the every day maintenance chores that one does with an old car....
And, yes, you do need to supply a new rotor/cap occasionally. Has nothing to do with the PITA of setting and resetting points.
Edward
E.B. Wesson

This thread was discussed between 16/06/2012 and 17/06/2012

MG TD TF 1500 index

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