I have also had a rotor, not in a TR, fail. It would run great with no
load, but as soon as a load was placed on the engine is would run just
terrible. Once the rotor was replaced all was well. On inspecting the
rotor under a magnifying glass you could just make out a track that ran to
the outside edge of the rotor so that under load the engine was putting
spark to the plug just in front of the one that it should have.
Rod Trunnell
-----Original Message-----
From: owner-triumphs@autox.team.net [mailto:owner-triumphs@autox.team.net]On
Behalf Of MMoore8425@aol.com
Sent: Friday, July 14, 2006 3:17 PM
To: foxtrapper@ispwest.com; 75TR6@tr6.danielsonfamily.org;
triumphs@autox.team.net
Subject: Re: [TR] Do Rotors Really Fail?
In a message dated 7/14/2006 10:03:31 AM Pacific Standard Time,
foxtrapper@ispwest.com writes:
Rotors don't wear out and need replacing nearly as often as parts
manufacturers would have you believe. While I've had rotors fail
mechanically, that is actually quite rare.
You get a couple of things going on under the distributor cap that cause
the
rotor, and cap, to wear out.
The rotor spins against the carbon button in the center of the cap. This
produces carbon dust that coats everything. That promotes arcing to ground
and not the plugs. Once this starts, usually called carbon tracking, it's
remarkably difficult to stop it. The carbon tracks get embedded into the
plastic and wiping doesn't remove them.
As the spark jumps across the small gap between the rotor and the cap lug
it
produces an arc and blasts a little bit of the metal off. Make it a soft
metal like many cheap caps use, and you can really wear things away after a
few million arcings. Now you've got a great big gap instead of a small
gap.
Which promotes misfiring. The metal blasted off by the arc is usually
vaporized and gets to redeposit itself inside the cap just like the above
carbon does. Again, promoting arcing to ground and such.
While it would sound like you could clean up the rotor and just replace the
cap, that will generally wear out the carbon contact button in the center
of
the cap in short order. The rotor gets worn from the previous carbon
button, and doesn't match up well with the new one, and grinds it down.
Sorta like putting new brake shoes on nasty brake drums, the shoes wear out
quickly as a result.
Wipe down the inside of the rotor and cap to prevent carbon arcing from
every occurring. Dress the contact points on the rotor and the cap. Do
that and you can add many years to the life of the components.
The Jaguar group has had a lot of failures of newly maufactured rotors.
There seems to be a manufacturing problem. I think it has to do with arcing
through the plastic to the distributor shaft.
Best, Mike Moore
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.1/389 - Release Date: 7/14/2006
=== This list supported in part by The Vintage Triumph Register
=== http://www.vtr.org
|