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MG TD TF 1500 - Petronix Ignition

Need some help here. I'm trying to have a Petronix installed in the TD. I've had one in the B for 3 years and couldn't be happier with the product. I purchased a positive ground for the TD, but when installed, the power drops considerably. Put the points back in, power returns. I've been through the history of this BBS and found some info by folks who have put the Petronix in their TD, and they all expressed satisfaction with the results so I know the Petronix works in the TD. Has anyone experienced this problem, and if so, how did you fix it?
Thanks!
Robert Dougherty

I know it's a dumb question, but have you checked the timing using the pertronix vs. the points? The distributor is going to have to be moved because the magnetic pickup on the Pertronix is going to trigger the spark at a different angle than the points would open. The only to check this is with a timing light.

You should use a slightly larger spark gap with the electronic ignition (.035 instead of .025), but that probably would not cause a power drop if you didn't open up the gap, it just would reduce the advantage of having the higher voltage of electronic ignition.

The other things to check would be to see if the Pertronix is somehow interfering with advance. (Too long mounting screw in mounting plate, perhaps?) Don't discount the possibility of having a defective unit. I can't even count the times I've gotten brand new parts that didn't function correctly. I'm sure there are several possibilities I haven't thought of.

Hope this helps, MB
Mark Barrington

Mark,

I had an intitial problem after installing the Pertronix in my TD. It was my fault. I failed to leave enough wire slack inside of the distributor for the advance to work. I had pinched the black wire. Once I fixed it everything was fine.

BTW, you can set/check the timing with a light bulb just as if you were using points. Pertronix uses a Hall device sensor that is DC coupled. Unless you have changed the coil there is no reason to open up the gap on plugs.

Bud Krueger
Bud Krueger

IMHO, set the plugs @ 028, w/ stock coil & pertronix ign. 035 is too much. [oem is 020-022] reason, larger gap = a larger area for the spark to travel/ignite the mixture.Coil capacity remains the same, but dwell time is probably longer. works for me.Total advance should be 34 -36 deg. BTDC @ max adv,approx. 3,000 rpm. This should be about 5 deg. BTDC for early cars/ may be as much as 10 or 15 deg BTDC for later cars as the dist. advance is less on later cars.When the shifter rattles, it's too far advanced. Kep the shiny side up! Len
Len Fanelli

Bob,

I'm using the Pertronix on my TC and loving it - only suggestion is for you to make sure you're connecting it correctly to your coil. Hooking the coil backwards can reduce the spark, hence the power.

Gene
Gene Gillam

This thread was discussed between 08/05/2002 and 10/05/2002

MG TD TF 1500 index

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