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Minor 1000 Distributor Dwell Angle/Dynamic Advance

Posted: Sat Oct 25, 2008 10:27 pm
by malcjohn
I am servicing a 1965 Minor 1000 for the son of a neighbour and wish to know the dwell angle for the Lucas DM2P4 distributor.
Also what should be the dynamic ignition advance for this distributor and assuming the vacuum pipe is disconnected at what engine speed should this be set?
With thanks in anticipation,

Malcolm Johnson

Posted: Sat Oct 25, 2008 10:46 pm
by bmcecosse
Welcome to the Forum - lots of new members these days !
Just set points to 15 thou gap. Don't worry about dwell angle - there is likely to be too much wear on the 40 year old dizzy!
Dynamic advance will be stamped inside dizzy on one of the little bob weights - whatever figure is there must be doubled for engine advance (because dizzy runs at half speed) . Typically it will read '13' - so 26 degrees advance. This added to the static advance of ~ 5 degrees gives 31 degrees total advance. Usually the total advance is reached by about 3000 rpm. Well worth checking the vacuum advance is working - many do not! Either leaking diaphragm or seized mechanism. Without vacuum advance the engine runs poorly and wastes fuel. Best final setting of ignition advance is done by ear - advance until slight pinking when flogging up a hill - then back off very slightly so NO pinking (perhaps just slightest trace under initial acceleration). It's then set to the best possible 'running' position for that engine.

Posted: Sat Oct 25, 2008 11:53 pm
by MoggyTech
Dwell angle is 58 to 64 degrees. Ignition advance starts at 800 RPM (engine revs). Dwell setting is more accurate as it compensates for any wear in the dizzy bearing.

Posted: Sat Oct 25, 2008 11:54 pm
by mike.perry
Correct me if I'm wrong but shouldn't a 1098 Minor have a 25D4 distributor? Wasn't the DM2P4 used on Series II or 948?

Posted: Sun Oct 26, 2008 12:03 pm
by bmcecosse
25D is certainly the better dizzy - with the assymetric cam lobes to cut down the 'bounce'. But many different versions - and after 40/50 years who knows what's original now !