DCOEs & Distributors

[Jay Laifman]

Found another reference that gives these two for the H120:
Lucas 23D4 (no VA) : 41239
Lucas 43D4 (no VA) : 41454 or 41556

Another source says https://mgaguru.com/mgtech/ignition/pdf/lucas_distributor_specs.pdf:
41239 Rapier Holbay H120 engine
41454 1974-76 Hunter GLS
41556 1969-75 Dodge (Commer, Karrier, Renault Truck) Imp Van (HC), 1969-75 Talbot Imp, Chamois

It does not have curve info for the second two. But for 41239, it has the info above (probably the same source):

RPM 1 - 3000 Advance1 ±1 - 13
RPM 2 - 900 Advance2 ±1 - 11
RPM 3 - 400 Advance3 ±1 - 2
no advance below - 250

 

[Jay Laifman]

For anyone who cares, I found the chart online for all the Lucas distributors (the other link was bad, it's now https://mgaguru.com/mgtech/ignition/pdf/lucas_distributor_specs.pdf). Here are all the Alpine related cars that are in that Lucas list (distributor degrees and distributor rpm):

Note that it's hard to compare because each distributor was noted at a different RPM. It could be that the 1 is the same as 2 and 3, and the SV and Holbay could be the same.

 

[Jay Laifman]

Also, for the Distributor 123 options above, it looks like 2 and 7 are the closest. Looks like 7 has a little more initial advance and more higher advance, with 2 just below. However both of them are a tad lower initial advance than a stock 5, and definitely slower than the H120.

 

[jdoclogan]

When I did the twin 38s DCOE installation on my Harrington Le Mans I sent the 25D4 distributor to Jeff at Advance Distributors. He did a mechanical setting for my DCOE setup (No Vacuum). Interesting that at the SUNI VII concourse judging I was dinged a point for not having a vacuum hose. The latter statement is intended as a chuckle moment.

 

[Jay Laifman]

I'm kind of in the same boat. When I switched to Holbay, I had a mechanic who did Lotus race cars help on the engine. He recurved the stock distributor with the springs and weights he used for some Lotuses. I have no idea what they are. And I have nowhere to put the vacuum hose either.

 

[Jay Laifman]

Adding this info from another website (not my words):

I dragged out the Hunter WM last night before I'd read your responses, which lists the dizzys for Hunter GLS / Holbay engine as ;

Dizzy : Application no
Lucas 23D4 (no VA) : 41239
Lucas 43D4 (no VA) : 41454 or 41556
Lucas 45D4 (VA) : 41604

The first 2 make sense as my understanding is that the 43D4 is bascially a more compact, reliable and better performing replacement for the 23D4 (as per 25D4 / 45D4 comparisons but without vacumn advance).

 

[Jay Laifman]

In case anyone else is interested, I found this a great read on understanding advance curves. https://mgaguru.com/mgtech/ignition/pdf/tuning_lucas_dist.pdf