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MG TD TF 1500 - Advance curve for modern fuel

I have searched the archives and found either very little information or things that don't seem right. I hope it won't enrage too many folks to revisit this topic one more time.

I have TD/C 15185 which two previous owners seem to have tinkered with since the distributor (40162D with asymetric lobes)has both primary and secondary advance springs snugged up tight rather than the way things normally are.

There is a link in the archives which shows a "Late TD/TF advance curve with 25 degrees total advance occurring around 3000 RPM, and no evidence of a break point where the secondary spring normally would engage and slow the rate of advance.

Question 1: Is it possible that the advance on some cars should be linear from 500 to 3000 RPM, with the two springs working entirely in parallel?

Question 2: Since I am using 93 octane fuel to avoid the alcohol, what sort of advance would be more appropriate. I have the means to spin the distributor, measure the advance over the normal range, and select springs to create the desired curve.

Thanks in advance, Neil
N.W. Dwyer

Neil, you want all advance in by 3,000 RPM, 12 degrees distributor advance = 24 crankshaft degrees, + 12 static advance = 36 degrees total. You will have to weld up the outer edge of the advance holes & grind to limit the distributor advance to 12 distributor degrees.
Len
laf48@aol.com
914 420 8699
Len Fanelli

Or you can send it to Jeff Schlemmer at Advance Distributor, and have him completely recondition the distributor, and properly set the advance curve to your engine specs and needs. It's some of the best money my engine customers spend on their rebuild!

Tom Lange
MGT Repair
t lange

Jeff rebuilt the distributor on our MGB, which would never run just right, new carburetors and all. After the rebuild, the engine runs beautifully. He recommended keeping the points rather than going electronic, which I did. The engine has more power, runs smoother and idles down better than ever. He knows his stuff and I would take his advice if he offers it! PJ
Paul S Jennings

Thanks to Len for the info, and to Tom and Paul for the recommendation of Advance Distributor. All of us are in this car hobby for a reason, and I guess I would rather bench-test a distributor than drive the car. I will keep Jeff's number close at hand in case I really hose it up!

What a fantastic resource this forum is! Neil
N.W. Dwyer

Moss has the best distributor bushings!









Len Fanelli

This thread was discussed between 26/05/2014 and 27/05/2014

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