MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - converting to electronic ignition

I installed a pertronix in 1980 mgb with 45D distributor. Points and condensor were connected to a small black box that was not wired into the coil. Car wont start connected to the box but runs with pertronix hooked direct to coil. I cannot find reference to the box in my Haynes Manual or anywhere in the archives. When I started the car it idled at 2,000 before the install it idled nicely just below 1,000. I found my strobe light is broken and I have adjusted timing as best I can until I can purchase a new one on Saturday. Car drives well, but I cannot seem to get the idle to maintain below 1,000. When I turn on the headlights, the idle dips so low the car wants to stall. Is this because I cannot get the timing correct without a timing light? Distributor is in good shape, car has 93,000k and typicaly runs very well.
Gordie

I have a 25D, but I found Pentronix has different wiring sckemes. They helped me
Frank Baker

If you have a North American 1980 it had electronic ignition from the factory, one of two types. If it has points, and they are connected to a black box, then it is an after-market PO mod. A Pertronix *should* be connected directly to the coil, but make sure the distributor has a ground wire conencted between the moving points plate and the body of the distributor. If it has points it should have anyway, but check to be sure. A 1980 would originally have had a 6v coil and external ballast resistance, which can affect how the Pertronix is wired, but again this could have been replaced with a 12v coil and no ballast, or even worse a 12v coil *with* the ballast still remaining.

A timing light is certainly the preferable way to set the timing, although in a pinch you could use static timing, 7 degrees seems the norm where it is given for late-model cars. Slowing down that much with just the headlights points to a very poor state of tune - or very powerful headlights!
Paul Hunt 2

This thread was discussed between 28/06/2007 and 29/06/2007

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.