Lotus Elan and Lotus Elan Plus 2 Forums

Hi folks

I am in the process of rebuilding my 2+2 engine and was thinking of fitting electronic ignition. My engine has a 23D4 dizzy, (before it was burnt) but, can someone tell me what is the difference between a 23D and a 25D because as I death its mostly the 25D that's advertised. I hope to fit the side entry cap, does the same cap fit both dizzys?
Any help or advice will be very helpful.

Hi

The Lucas 23D distributor is a non vacuum advance distributor where the ignition timing relies solely on weights within the distributor to advance the timing as engine speed increases. The 25D unit has a vacuum diaphragm unit attached to the distributor and this assists the change in ignition timing required with some engines at lower RPM. The diaphragm operates a rod attached to the contact breaker base plate and at low RPM when the vacuum within the inlet manifold is at its highest ( butterfly is shut @ tickover) the baseplate moves and changes the position of the contact breaker heal in relation to the lobe on the cam, thus altering the ignition advance.

The same side entry cap will fit both distributors but you will require the 23D type distributor with side entry cap.

Nick

I recently swapped out my tired 23D4 distributor for a new Pertronix D190509 Flamethrower distributor and coil. The difference in performance is quite noticible. The Pertronix D190509 has a side-entry cap too. I got mine new on eBay. It's probably comparable in price to having a tired 23D4 professionally rebuilt.

Gary
'71 Sprint FHC
Miami, Florida

Thank you Nick and Gary for all the advice you both have given. I had got so confused when I looked on various websites regarding distributors, but now all is clear. Thanks again.

Gary, How easy was it to install, and how was the change noticable? I've thought about doing this many times. Thanks, Dan

I bought a Tony Thompson electronic distributor/ lucas coil/ magnacor leads package for about ?250.
The Distributor Doctor quoted me about ?170 to refurbish my 23D4
I haven't tried it yet but it all looks good.
Kev.