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Re: Petronix ignition

To: <>, <>, <>
Subject: Re: Petronix ignition
From: "Lawrie Alexander" <>
Date: Wed, 19 May 1999 07:12:12 -0700
In the glorious tradition of this (and other) lists, I will start out by
saying that I have no answer to the question that Steve asked, as I have not
tried the Pertronix in a T-type. However, I would like to share the
discovery, just yesterday, of a serious problem with a Pertronix unit that I
installed in an MGB.

After installing the Pertronix, I wanted to check that the advance unit was
working. A vacuum pulled on the unit made the plate move when I looked at
the distributor with the cap off. However, the engine did not seem to
perform as if it was receiving full advance. I disconnected the vacuum pipe
at the carburetor and applied vacuum while the engine was running. No change
in idle speed! Off with the cap, checked the plate again - still moving. A
break for lunch to ponder this seemingly impossible situation.........

After lunch, I removed the distributor for closer inspection. Eureka!
Problem discovered. This particular Pertronix unit was machined in such a
way that the mounting plate that attaches where the points used to be was
too wide. In other words, its outer edge fouled the cap, thus preventing the
base-plate from being rotated by the vacuum unit. The fix was to remove it
and sand off the excess metal on a belt sander. (A file or bench grinder
would work, too.) When replaced, it made a big difference in how well the
engine ran.

So, all of you who have fitted your distributors with a Pertronix unit, may
I suggest you check to make sure that your distributor cap is not
interfering with the P-unit where it attaches to the base-plate. Perhaps
those of you who do find a problem would be so kind as to let me know so I
can relay the information to the supplier if - indeed - mine was not an
anomalous situation.

British Sportscar Center

-----Original Message-----
From: Steven Tritle <>
To: <>;
Date: Wednesday, May 19, 1999 6:43 AM
Subject: Petronix ignition

>Has anyone tried the Petronix ignition in their TD? If so, what is the
>I was tempted to purchase one at Carlisle but didn't.
>52 TD

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