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TR2/3/3A TR3 Distributor

oxendine

Jedi Hopeful
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Still fooling around with my 1960 Tr3 in trying to get it to run and or run properly. Read another post as to a bad condenser being a problem. I have not gotten into that yet. I was just wondering if an MGB dizzy of around 1969 be the same as a TR3? Got lots of those.
 
Almost certainly not exactly the same. Might be close enough to work; but if you're convinced the MGB dizzy is good, why not use it's points & condensor in the TR unit?

Or just blow $10 @ TRF on RFK1291, which includes points, condensor and 'improved' rotor. Once you get it running, you can always swap back to the old components (which are likely fine) and keep the new ones for the next tune-up. Or just keep the old ones for on-the-road spares.
 
I've mentioned it before but perhaps it bears repaeating... You can literally hold the entire ignition system in one hand:

One-Hand.jpg


Why not get a spare everything? Great for diagnosis and the ultimate 'rainy night don't have time to figure it out' on the road repair to get you moving again.
 
Randall and Geo’s advice is excellent. I do remember a time going into a local parts store and purchasing a distributor for a tr3/tr4 and they called the warehouse in Portland and found two rebuilt ones. I had them sent up and looked them over and as we were talking the cross reference thing came up. If I remember correctly, a 60’s Sunbeam and MG had the same part number. If you have a parts store that is kinda old school, ask them for a distributor 67tr4 and then see what the computer says.
Steve
 
But note that even a 67 TR4 has a different advance curve than a 60 TR3A. Here's a chart I put together, showing just a few of the many different centrifugal curves used by the factory on TR2-4A. (Vacuum was also different, I just didn't plot it.)
 

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I really like your chart Randall and I am sure you have done your research, but I thought it was just the opposite with the tr4A having more advance than the tr3.
Steve
 
If you have a reference, Steve, I'd like to hear it. I got the numbers in the chart from Marcel Chichak's database, and he admits there are probably errors lurking in it. But the TR4/A workshop manual seems to have the same numbers.
 

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