Lotus Elan

Anyone seen this type of distributor?

PostPost by: dgym » Fri Feb 02, 2018 10:22 pm

In trying to sort some issues after an engine rebuild, it has come to my attention that my dizzy is of a type not noted anywhere for an Elan or even at all on the internet!
Any ideas?
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PostPost by: Elan45 » Sat Feb 03, 2018 2:12 pm

The number is not the one speced ( IIRC-40853 ) for an early Elan, but it is the same type, a 23-D-4 non-vacuum advance dizzy. Almost all race cars and hot street cars of the had these non-vac distributors. Most people would look at this and assume it was standard, but for the actual number. Probably has a slightly different advance curve or total advance, but unless you have specific running issues, I'd leave it alone.

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PostPost by: vincereynard » Sat Feb 03, 2018 2:56 pm

+1 to that.

It would be interesting to get a strobe and check its advance curve.
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PostPost by: types26/36 » Sat Feb 03, 2018 5:32 pm

The Lucas Distributor Catalogue does not list a 40757B (assuming the number is B) but it does list a 40757A.
It also does not list the application for the "A" but does give its specs.
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PostPost by: vincereynard » Sun Feb 04, 2018 9:22 am

"The Lucas Distributor Catalogue" That's a useful doc.

What does it say for 41189A?
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PostPost by: nmauduit » Sun Feb 04, 2018 10:31 am

vincereynard wrote:"The Lucas Distributor Catalogue" That's a useful doc.

What does it say for 41189A?


I believe the data are from :

http://www.starchak.ca/tech/pdfs/lucas.pdf
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PostPost by: john.p.clegg » Sun Feb 04, 2018 10:33 am

Good man...
Just what I was looking for...

John :wink:
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PostPost by: vincereynard » Sun Feb 04, 2018 11:32 am

nmauduit wrote:I believe the data are from :

http://www.starchak.ca/tech/pdfs/lucas.pdf


Excellent. Many thanks. I note there is no distinction for the BV engine.

19-feb.-04-11.24.jpg and


Distributor Revs - Initial 12
> 600 +1 = 13 (Crank revs 1200)
> 1000 + 5 = 18 (--------------- 2000)
> 3250 + 7 = 25 (--------------- 6500)

Something like that?
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PostPost by: oldelanman » Sun Feb 04, 2018 3:07 pm

vincereynard wrote:Distributor Revs - Initial 12
> 600 +1 = 13 (Crank revs 1200)
> 1000 + 5 = 18 (--------------- 2000)
> 3250 + 7 = 25 (--------------- 6500)

Something like that?


Not quite.
Distributor runs at half engine speed, so double distributor advance and add to static advance to get total crankshaft advance at each speed.....
1200 rpm 2+12 = 14 deg
2000 rpm 10+12 = 22 deg
6500 rpm 14+12 = 26 deg
Not sure how accurate those figure are however as they show some advance at 1200 rpm whereas both the Workshop Manual and Miles Wilkins say no advance below 2000 rpm for that distributor !
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PostPost by: vincereynard » Sun Feb 04, 2018 4:29 pm

Understood. Each dissie degree is 2 crank degrees.

Whether Lucas or the Official Workshop Manual is the more inaccurate is a moot point! Lotus does have form on the advance front!

The Lucas figures closely match, (in shape and progression), the graph drawn for a Distributor Doctor restored for a QED cam.

So when the internal advance limiter is marked as 10 degrees that means 20 crank degrees?
Add initial gives the maximum.
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PostPost by: oldelanman » Sun Feb 04, 2018 6:09 pm

vincereynard wrote:So when the internal advance limiter is marked as 10 degrees that means 20 crank degrees?
Add initial gives the maximum.

Exactly.
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PostPost by: 10kph » Sun Feb 04, 2018 8:54 pm

Further bedtime reading about Ecm curves and deciphering Lucas codes at.
http://mgaguru.com/mgtech/ignition/pdf/ ... s_dist.pdf
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PostPost by: vincereynard » Mon Feb 05, 2018 10:42 am

10kph wrote:Further bedtime reading about Ecm curves and deciphering Lucas codes at.
http://mgaguru.com/mgtech/ignition/pdf/ ... s_dist.pdf


Thanks for that. Another lengthy list of .pdfs.

What would be useful would be a list of the spring strengths they used. Each must have a Lucas part number presumably. So a 41189 would be fitted with a XXXX primary and a YYYY secondary.

I've tried the good Doctor but answer came there none.
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