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Advance curves


haggis
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Hi folks, can anyone supply me with advance curve data for a vitesse mk2, running Lucas distributor please. And if there is anyone running a 123 tune + dizzy on their late vitesse or Gt6 that might also supply their curve data, that would be greatly appreciated. 
 

thanks

Hag 

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Pitch dark this morning, and the clocks went back too, so all of the terrible TV programmes that should have started at 7am didn't really start to 8am.... :)

This any use, Haggis?

http://mgaguru.com/mgtech/ignition/pdf/tuning_lucas_dist.pdf

https://www.sbmsclub.com/wp-content/uploads/2018/03/lucas-dist-chart.pdf

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John D, you bet I looked at your curve, good to see some crank advance figures rather than centrifugal, as that’s what the 123 uses, very useful to compare to all other data I’ve gathered. And thanks Pete for the vacuum data, I’ve searched the internet for them, hopefully I can translate them into something I can get the 123 to understand.
It’s all new to me. 

thanks again 

hag 

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dont forget the advance centrifugal is always decelerating  thats how they and we tested dizzy against the specified data

as i said this goes against the expected norm but its the way they do it  ,,,,,,,so take it up to 3000 ish+  and back it off checking as you go 

if you then re plot the curve accelerating you get a very different result and it shows the hysteresis of the climbing and descending variance in the springs and weights 

i dont know why the data was done this way  

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without doing a test i dont know ,  but its specified as decel so thats what the   WSM  says 

we tested  dizzy's returned under warranty and only matched results with the approved test , 

long time ago now , seem to recall lucas  was definitely decel .........but an american unit as tother way round ( but that was  80's  electronic)

rules of confusious  Ha 

Pete

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My guess would be that the mechanical advance could suffer a bit from stiction. If so, it will tend to be over-advanced on the decel test, which is probably the condition you want to avoid, and are testing for. Ideally there should be not very much difference, and with programmed ignition you can be pretty sure there won't be. So the WSM spec being "test on decel" means it's the maximum safe advance, which is probably what you want for setting up a 123-tune. At a guess, of course. 😉

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