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MG MGB Technical - hesitation with 123 distributer

Have just installed a 123 distributer on my 1970 MGB GT. Not being too sure about the engine model (see htread on which engine), I have opted for setting 6 on the distributer. All fine, the car is quieter and pulls better then previously, but has a hesitation at about 1500rpm.
Under heavy acceleration there is no hesitation even in 4th, but in general use the engine seems to miss/die for a second and then pick up again. Beyound 1500rpm no problem, below it no problem....
Is this due to the setting, or is it a common thing that everyone just accepts?, or is it due to something else. It's not a big problem, but would be nice to sort out.
Thanks
Mike
Mike

I think its fair to say you have the wrong advance curve for your particular engine. You need the engine number or the old distributor number to set it correctly. Mine is a 1978 GT and I used setting A. I just installed mine recently. There's no flat spots at all and the engine spins like a turbine now! Did you go for the one with or without the vac advance, just out of curiousity?
Ross Kelly

I got a 123 recently precisely to get rid of flatspots at 1500rpm ... it worked. In my 1980 GT the 0-60 time has dropped from about 18 to 15 seconds and fuel economy has improved.

I too use setting A and have no vacuum advance as the vacuum pipe on the original setup had been plugged and I saw no reason to change ie.
Geoff E

Sorry to hijack the thread, but Geoff, did you set your timing to TDC?
Ross Kelly

Mike

Check you have a good thick oil in your dashpots, 20/50 or straight 30 weight. Are your spark plugs in fine fettle?


Peter
peter burgess

Ross

I actually set it to TDC this morning. Following some garage work a week or two ago, I noticed pinking last week. Hopefully, it will be OK now, I'll soon know.

Are you running on TDC?
Geoff E

Yeah mine is set to tdc and there's not a hint of pinking. I have to say the car really pulls like a train with the new distributor in now, even with the carbs the way they are, and it never misses a spark. I have a pertronix flamethrower coil with it. Its a very good product I have to say.
Ross Kelly

This thread was discussed on 07/04/2008

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