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Stumper

To: <mgs@Autox.Team.Net>
Subject: Stumper
From: Robert Alan Reisse <rareisse@postoffice.worldnet.att.net>
Date: Mon, 22 Nov 2004 17:42:43 -0500
Hi,

I have a problem that stumps me a bit.

Last month while driving through a rally, the car just quit.  Luckily I was 
the first off and we had a crew trying to figure out what was wrong.  We 
had spark coming out of the coil, but nothing at the plugs.  Changed the 
points, condenser and still no start.  So I ordered some replacement parts 
and set things up to go through things carefully to make sure we made no 
mistakes in the field and found a few and corrected them, but still no fire 
at the plugs.  Replaced the rotor and the engine sprang to life.  It ran 
fine for about five minutes and then died.  Pulled the rotor and found a 
ring of black stuff around the rivet holding the brass contact to the 
rotor.  The engine would not run with either the original rotor or this 
replacement after that.  Luckily I had purchased two new rotors. The second 
one did the trick and the engine ran fine for the rest of time that I 
worked on it.

So what happened?  Why did the rotors fail? How can I prevent this from 
happening again? Should I carry around spare rotors?  Points and Cap, yes, 
but I never really consider the rotor to go bad other than a little bit of 
wear.  Not total replacement.

Other comments:

The original rotor was very difficult to get off.  There is zero resistance 
between the outside of the plugs and the chassis as measured with my 
ohm-meter.  Anyway if the rotor is bad the charge has to go to the center 
shaft of the distributor which is tied to the engine, i.e. same potential 
as the outside of the spark-plug.  So no bad engine ground.

Thanks for your comments.

Bob Reisse
69 MGC
76 MGB




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