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Distributor springs

From: Cyril White
Fromemail: c.white@forges.freeserve.co.uk
Category: Technical
Remote Name: 192.168.1.1
Date: 09 Feb 2003
Time: 23:05:45

Comments

I pass on conversation with Barry. The Dm2 changes rule out cross use of springs. However there is some good info here and it might come in useful. The reference to Maestro's -stems from an article in practical classics where they converted-/ changed a mini Diz to use an electronic ignition version from a scrap car and I wondered if it was worth while Jowetteers going down that road.

Note that the hooks on DM2 springs are at right > angles to each other, not in the same plane, as 25D type are. Having > said that 1960 dated DM2 type Dizzies have the 25D internals and the > later Baseplate. You can tell from the outside by looking at the low > tension terminal. It slots into the body as the 25D type does. This > must have been near the change to 25D type. > > Now to your Moss springs. My set contained 5 springs. I used the > heaviest spring which was .039" wire size, .718" long between ID of > hooks, .272" OD of coils and 5.5 turns. There is another heavy spring > of.039" wire, it is .638" long. Dont use it. The other spring to use > looks the same but wire size is .035", it is .626" long, between ID of > hooks, .265" OD of coils and 6 turns. There are 2 lighter springs not > required. > > With a 10║ Cam (These vary a degree or two but are close enough) The > one I used gave me the following result. > > 1300 - 11║ Max > 650 - 4║ > 500 - 1.5║ > 250 - Nil > These are at the Dizzy readings, double RPM and Degrees for > Crankshaft. These results are well within Lucas specs for Jav dizzy. > > Now at about the same time a customer sent me a 1971 Morris 1300 Dizzy > for repair. It was 25D4 41257E and had a 10║ Cam. Here are its > specs.( I dont know if it was manual or auto and there could be a > difference) > > 2500 - 9-11║Max > 1400 - 5.5-7.5║ > 400 - 0-1.5║ > 150 - Nil > > I noted it was fitted with 2 identical springs so I ran it up with > just one fitted. > > Results were: > > 1450 - 11║ Max > 1300 - 9║ > 650 - 2║ > 500 - 1║ > 250 - Nil > > Again this would be close enough to suit a Javelin. 25D dizzies will > run OK with just the 1 spring. Some of the Hitachi Dizzies fitted to > small Nissans are fitted with 1 spring only, from the factory. > > Here are the Lucas specs again for the Javelin: > > 1300 - 9-11║ Max > 650 - 3-6║ > 500 - 0.5-3.5║ > 250 - Nil > > Regarding the Maestro Dizzy, it still has to be graphed correctly and > many Minis use more than 11║ Max > > Hope this helps Cyril, let me know in due course. > > Regards > > Barry Emms B&L-EMMS@xtra.co.nz


Last changed: November 19, 2008