[Healeys] Backfiring

[Leonard Berkowitz]

I think I finally solved the backfiring problem I have been suffuring with.
As a result of the car stumbling and barely getting me home the last time I
drove it before the snow, I opened my distributor to adjust the points. To my
surprise I discovered that the center of the rotor and the corresponding
contact in the cap were burnt badly.  I cleaned up the rotor and switched the
contact in the cap and the car sprung back to life. Ran nicely and didn't
backfire.  I proceeded to change the rotor and just drove the car.  Needless
to say I was thrilled.  Drove beautifully and didn't backfire at all.
Now the question is - Why did the rotor and contact burn so badly? All parts
are relatively new.  Cap, rotor, points, condenser, coil and wires have all
been changed in the recent past. Any thoughts?