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MG TD TF 1500 - LS Pertronix Question for Bud Kreuger

Bud - thanks for the information on the LS versions of the Ignitor I and Ignitor II pertronix units.

Could you explain the "lobe sensing" (LS) feature and the advantages of it - I could not find a footnote on the site about the lobe sensing feature.

The chart also mentions that use of a lobe sensing unit "requires modification of distributor" - could you describe the modification needed?

Thanks in advance Bud
DLD

Perhaps the greatest thing about the lobe-sensing (LS) version is that it does not use a magnet collar. The module senses the position of the distributor cam. The electronics in the module is quite different from that of the original Igniter. Sensing the variation of the magnetic field perturbation by the cam is not a simple switch procedure. This technique is bound to be affected by RFI created by the firing of the spark plugs. Two forum members have seen what happens when you try operating an LS unit with hard wire cabling. A significant complication is the screw-in caps on the distributor.

IMHO, no one should install an Igniter on the original points plate. Purchase a new plate and install the module on it. That way you can keep the points system in your toolbox to make yourself feel better. Installing the LS module requires that you remove the points and the capacitor. Here's a portion of the installation instructions for an LS12P unit:

Also, IMHO, I would NOT stay with positive ground.
Bud


Bud Krueger

Bud - thanks for that clarification - I have been reading up online from other car forums and see too that the Ignitor II also varies dwell at increased RPM - increasing spark power at say 3,000-5,000 RPM.

I may stay with the regular Ignitor - I just need the correct magnetic collar - the TD was fitted with an MGB unit and was out of phase with the rotor.
DLD

My main reason for being attracted to the LS version was to get around that Magnet collar. It is responsible for the only Pertronix-related failure that I've experienced. See http://www.ttalk.info/Failure.htm for some details. Bud
Bud Krueger

This thread was discussed between 30/05/2015 and 31/05/2015

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.