123 Ignition's 16 timing curves... which one should I use?

Started by Armycook, April 19, 2017, 12:44:52 PM

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So i was able to purchase the 123 Ignition. Found out my distributor driveshaft was 180 degrees out so i fixed it and cables aren't too snug anymore and the ignition timing settings are within reach and visible now. Did all the installation according to directions by rotating it just before the green light turns on. Verified it with timing light and it's at 10 degrees. So now what? I've read in other forums that a good starting number for classic minis is 6. i've heard different ways of doing this properly by taking it to a dyno shop but it's too expensive. I have a Kent 266 Cam on my 1275 and need some tips how to pick the right settings to tune it. I drive my car a lot on the freeways btw.


Does the 123 have curves posted anywhere?  If you can find curves we can get you a good idea which one to use.


Well there you go.  I'll be trying the equivalent to the F curve on the 34 degree scale with a 266 cam and a bunch of other goodies.  My backup curve depending how F works would be E.


Did you see this "standard low compression small bore and big bore engines, low volumetric efficiency, low grade fuel" on the 34 degree page? Doesn't sound like your engine, Dan.

The 30 degree curve looks more like this engine....  "highly tuned small bore and big bore street engines, high volumetric efficiency"
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad


Pretty sure the aldon yellow goes to 34 and that's what everyone is running.  But let me research a bit more.


This may be what I read ages ago.  But now I'm curious what is recommended with high comp pistons.


Spoke to previous owner and told me compression ratio is 10:1


John Gervais

This is the graph of the Aldon Yellow that I pulled off The Mini Forum.

With my 100AY Aldon Yellow (without vacuum advance - thanks Terry!), I set my ignition timing at 5000 rpm as close as I can to 31° BTDC. 

I check it at 1000 rpm and have 14°(ish) BTDC, but not exactly sure why.

31° (crankshaft°) minus 24° (12° distributor x 2) = 7°.

Can anyone offer an explanation?
- Pave the Bay -


I have bought a 123 ignition usb for a classic mini, but I'm trying to create the best curve for it and I not having any luck :(

Can you please try to help me?
I'm from Portugal, and my mini is a 1380cc engine,  with a Swiftune SW5, Flat Top Omega Forged Pistons, big valves, doble springs on the rocker assembly 1.5 ratio...

Please help me!!
Thank you very much for your time,
bruno cirilo