Lotus Elan

Ignition Advance (Part 2)

PostPost by: 2cams70 » Mon Jan 22, 2018 2:30 am

richardcox_lotus wrote:I have read a story of Lotus building their own looms after they?d moved to Hethel. However they didn?t check whether the workers were colour blind or not.

Urban Myth ???

You decide.........

Regards,
Richard


It was only the totally blind ones apparently that Lotus sent to British Leyland. They all got jobs working on Series 2 Jaguar XJ12's. It didn't matter whether you were sighted or not working on those because regardless you could not find anything under bonnet. In fact with a heightened sense of touch it was indeed better to be blind.
1970 Ford Escort Twin Cam
1972 Ford Escort GT1600 Twin Cam
1980 Ford Escort 2.0 Ghia
Peugeot 505 GTI Wagons (5spdx1) (Autox1)
2015 Honda City 5spd.
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PostPost by: vincereynard » Tue Jan 23, 2018 6:34 pm

I modified the curve by strengthening the primary and shortening the secondary.

And, far more by luck than judgement, it gave a curve that virtually mirrors the original BV advance.

screenshot-from-2018-01-23-18-27-05.png and


Thats a result!
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PostPost by: MarkDa » Tue Jan 23, 2018 6:43 pm

Vince
A result is a result however you get it!
Well done - now we know where to send our dodgy dizzies for doctoring!
It should give you a better pick up mud range I'd say.
Mark
Last edited by MarkDa on Tue Jan 23, 2018 7:38 pm, edited 1 time in total.
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PostPost by: Mazzini » Tue Jan 23, 2018 7:15 pm

Finally got round to finishing off the 123ignition distributor, it's easy to fit and simple to use, not cheap, but I hope, fit and forget.
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PostPost by: vincereynard » Tue Jan 23, 2018 7:56 pm

MarkDa wrote:Vince
A result is a result however you get it!
Well done - now we know where to send our dodgy dizzies for doctoring!
It should give you a better pick up mud range I'd say.
Mark


At best my bodging is a temporary fix.

I phoned Bestek and spoke to the most enthusiastic chap. He is offering a custom made system based around a Bosch electronic distributor. Which he maintains is super reliable. Plus a matching coil . Whole system, with delivery and VAT - ?220. Problem is, of course, The curve is fixed. After a rolling road session I would probably have to change it again!

Mazzini wrote:Finally got round to finishing off the 123ignition distributor, it's easy to fit and simple to use, not cheap, but I hope, fit and forget.

What settings did you decide on Mazzini?
123 system ?320 / ?330 plus the usual. Dependant on if Bluetooth or USB. Twice the price near as makes no odds. Plus fully adjustable.

So I have a decision to make!
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PostPost by: MarkDa » Tue Jan 23, 2018 9:04 pm

Glad to hear Bestek is keen and competitive.
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PostPost by: Hawksfield » Tue Jan 23, 2018 9:27 pm

Vince

I have used the 103TC from ALDON with good results its a 43D4 with max advance marked on the advance stop, I am sure its a Lucas looks different to your interior
I run it with a Lumenition optronic system been good for 20 years
Regards

John

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PostPost by: Mazzini » Wed Jan 24, 2018 10:17 am

I went for the Bluetooth version, I bought it direct from the manufacturer in the NL's, I think the UK supplier said that they only had the USB version in stock and couldn't quote a delivery date. The Dutch delivery came in a couple of days.

As I previously mentioned I fitted a different clamp tightening screw so that I could use the old square nut, this means the clamp can be tightened with one hand only. The spring clips that hold the cap in place are not sprung steel so they bend easily, but those are the only minor gripes, the distributor itself is superb, I am currently using the standard Lotus BV advance curve because it's a standard BV engine that I've fitted it to. I have a Q420 engine in my S3 which I will fit one of these units to and then the fun will start.

I couldn't really road test the Sprint yesterday as there was still a lot of snow, ice and salt on the roads, but a short trip on private roads showed that the car behaved very well indeed.

Once the distributor is in place it doesn't need to be moved again, everything is done from the iPhone app. I have a dear old friend whom is an auto electrician, he stopped by yesterday and fell about laughing when he saw the mobile app dashboard, he couldn't believe it.
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PostPost by: Chancer » Wed Jan 24, 2018 10:21 am

Tell the guy at Bestek what goes around comes around, it must be at least 20 years since he sorted me out, he was very young then, he was very lucky to have acquired a dizzy rig, they will be even rarer now.

Word of mouth still works in this age of social media, I had to laugh that he doesn't want his web site to be active, I feel the same about mine give him my regards and an apology for him being disturbed on a Saturday evening :oops:
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PostPost by: vincereynard » Mon Jan 29, 2018 12:40 pm

Chancer wrote:Tell the guy at Bestek what goes around comes around, it must be at least 20 years since he sorted me out, he was very young then, he was very lucky to have acquired a dizzy rig, they will be even rarer now.
Word of mouth still works in this age of social media, I had to laugh that he doesn't want his web site to be active, I feel the same about mine give him my regards and an apology for him being disturbed on a Saturday evening :oops:


I've phoned him twice and asked him to Email is product details but, so far, not a peep.

Mazzini wrote: I am currently using the standard Lotus BV advance curve because it's a standard BV engine that I've fitted it to.


As on Page 14 - 0 up to 2000, then a straight line upto 14 degrees at 5000 crank revs?

That's what I cannot duplicate. There is no primary to secondary transition. Perhaps there wasn't one on the original B.V. Both springs the same perhaps? Yet way different to the after market units generally supplied.
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PostPost by: nmauduit » Mon Jan 29, 2018 1:11 pm

vincereynard wrote:That's what I cannot duplicate. There is no primary to secondary transition. Perhaps there wasn't one on the original B.V. Both springs the same perhaps? Yet way different to the after market units generally supplied.

Chances are that the modifications you mention before may have concurred to your voiding one of the transitions : they are based on the difference between the springs, one being weaker than the other to provide low rev advance, then the other comes into play at higher revs thanks to its higher stiffness. Both parts of the mechanism need some play to operate (hence I would be cautious on the effect of "shortening a spring"), you may want to check approximately how it works by pulling on the centrifugal weights.

Springs, weights and platforms are available - though a bench setup to check them accurately within a distributor is a bit of work to make up...
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PostPost by: vincereynard » Mon Jan 29, 2018 1:37 pm

"There is no primary to secondary transition" was in regards to the original Lotus BV curve.

0 up to 2000, then a straight line upto 14 degrees at 5000 crank revs?
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PostPost by: nmauduit » Mon Jan 29, 2018 3:01 pm

vincereynard wrote:"There is no primary to secondary transition" was in regards to the original Lotus BV curve.

0 up to 2000, then a straight line upto 14 degrees at 5000 crank revs?

I'm not sure what you mean by "original Lotus BV curve"...

If I check Wilkins book p169 on my version I see 2 versions of curves for the 40953 which have 2 (non horizontal) slopes, i.e. 2 springs of different strength
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PostPost by: vincereynard » Mon Jan 29, 2018 4:46 pm

I was referring to the official lotus Workshop manual Page 15.

The Wilkins Book! I had not thought of looking there.
P168 , Half way down, right of page, under All Big Valve ,

12 static up to 2000 then straight line up to 26 maximum.
(S/E Weber is exactly the same line except for 2 degrees less static)
Same as the manual.

Most curves I can source are like the 40953 (Top of the graph).
A steep advance (primary spring) until about 2000 then the secondary adding to flatten the curve.
Giving a sharp kink in the line - hence "primary to secondary transition"

There isn't any with the 41189.
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PostPost by: Craven » Mon Jan 29, 2018 5:06 pm

I have in the back of my mind, limiting the Max advance to 26 deg on later engines was more to do with meeting emission regs than optimising engine performance.
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