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 - Zenith and Mallory Distributor

Has anyone ever installed a Mallory Dual Point Distributor on a MG with a Zenith carb? I can figure out the wiring but what about the vaccum unit which is connected to the carb? Does anyone have any thoughts on this or done this before?
MAX Max

Max, I have the dual point carb on my 73 low compression. I do not have a Zenith but I just closed off vaccum ports. I'm having a devil of a time getting the advance curve right. I have not been able to eliminate a high RPM skip. I have methodecly tried every spring combination I can think of and have reset the gaps with great care many times. Let us know how your dual points work out.
Ken Knize

The dual-point feature of the Mallory is superfluous, the MGB simply doesn't rev high enough to get the sort of problems that the dual point is intended to solve, as indicated by six, eight and twelve-cylinder applications with progressively reducing dwell don't need it either.

If you have a Zenith the original distributor would have used mainifold vacuum so use the same, and time it the same way. Running without any vacuum advance will significantly worsen cruising economy.
Paul Hunt

Paul, Mallory dual point does not have a vacuum advance, just centrifical. I didn't know that when I ordered it to replace my wabely dizzy.

Ken Knize

Ken,
I have the Mallory in my '80 B. I also experienced some of the problem your having at high rev. The Mallory has a problem at the condenser. I have burned out two so far and finally went to a Ford condenser to see if it would help. So far so good. My reasoning for the Mallory was due to my using the B in autocrossing and a few track day type events where I would be high reving. The mechanical advance advantage was to prevent pre-detonation when radically going from high to low revs thus avoiding grenading the engine. Another advantage was that the points do not wear out as fast. I rebuilt my engine and had it balanced and added a performance cam plus some other items to achieve my objective. I can run up to 7000 revs and not worry about the engine. The reason I say this is that if your purpose is to use your B for regular road use then I would not use the Mallory and go back to a vacuum advance unit with the Petronic replacement for points.
Just my $.02.
Kevin

Mike, After laying out about $225 as I recall I hesitate replacing the Mallory. As for the original it is trash. Can Petronic be used in the mallory?
Ken Knize


Max, I'm the guy with the webber pushing oil into
the air filter which, thanks to Doug & others, will
soon be resolved. My overbore engine had the ballast
resitor originally. I wired the Mallory as per their
website and installed a 12volt constant Jaguar coil.
Have had no ignition conerns-timing is advanced
about 10 degrees. Good luck, Nestor
Nestor

pertronix makes a kit for the Mallory. Mine is with vacuum advance. took it off due to condsensor problems and cost of pts and caps.!!!
DP Pantano

This thread was discussed between 18/04/2004 and 23/04/2004

MG MGB Technical index

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