Numpty question regarding Lucas Distributors

[pete east]

As posted recently, my Lumenition ignition came adrift lunching both the beam splitter (Chopper) and Sensor unit. Despite having its markings ground/polished off I managed to determine that I have a lucas distributor and have got replacement Lumenition parts from Burtons (Exellent company). Whilst cleaning/preparing the distributor for the new parts I could not see how advance was catered for (there is no vacuum advance set up on the unit) is the advance mechanism purely mechanical and if so how does it work, I ask this because the base plate to which the sensor is to be secured appears to be rigidly fixed e.g the base plate does not rotate around distributor spindle to provide ignition advance. It is perhaps testimony to how good the Lumenition system is that I have never had to touch it in 15 years. Also my tin tops have electronic ignition so I have literally forgotten the little I knew about distributors in the first place. any advice would be welcome.

Regards Pete.

[Nigel Riches]

Hi Pete, when you say "the base plate appears to be rigidly fixed" can you see some means of locking it, a small spot of weld or a screw of some sort?

 

I have heard of the advance plates being fixed in place but then another means of advance is used, a crank angle / throttle position software setup.

 

Sounds to me the plate is seized, might need some penetrating oil from the top, where the rotor arm is installed.

 

If you like I'll get out to the garage and have a look see, for what I can under the Webers, and report back, got to get the carbs off anyway, so a good excuse.

 

Regards Nigel.

 

1982. 5 speed, clamshells. B.R.G / Ali. The True Colours.

[pete east]

Nigel - Many thanks for your reply. I know that where a vacuum advance was used the dizzy has a vacuum chamber which actuated a rod which in turn pulled/pushed the base plate as required. Also some distributors are fitted with a mechanical advance using counterweights ?? I suspect/Hope my distributor is this type but would like to know if the advance is provided by the mechanism actually moving the base plate or does it achieve advance in some way whilst using a fixed baseplate. I guess I am hoping that if I re assemble the distributor with the new parts it is just going to work as normal. I have cleaned all the broken bits of the original Lumention system out of the unit including all the blades of the original chopper. Thanks in advance for any info you might provide.

regards - Pete.

[Crudders]

Hi Pete - from your description it sounds like my distributor, which is an Aldon modified Lucas.

 

You're right - it's mechanical advance only, achieved with weights and springs, which hide under the mounting plate. Two small screws and the plate is off IIRC. While you have it apart it's worth giving the mech advance components a good clean up and a drink of oil.

 

Crudders

[pete east]

Richard - Thanks also for your reply. I suspect my distributor is as you describe (at least I hope so) I will clean up and lubricate the mechanism as you describe and put the new Lumenition bits in keep my fingers crossed and hope that it fires ok. Hope to see you at the North Kent meet (and possibly the Fox & Goose ????)

Besr Regards - Pete.

[pete east]

To Richard and Nigel - Thanks for the advice. Got the new system installed, and it goes like stink! On reflection the the Lumenition sensor must have gradually come adrift, because the performance dropped off only very slowly. But its amazing that the system continued to let the car run even when it was adrift. Also got the MOT done today so I am a happy bunny - Thanks again

Regards - Pete.