Lotus Elan

Ignition Timing Advance Help

PostPost by: William2 » Sun Sep 19, 2021 1:04 pm

I am trying to adjust the timing on my SE/Dellorto carb Elan using a strobe. As far as I know the distributor is a 41189 23D4 type which has always been on the car so I can't tell how worn it is. My estimated readings from the markers on the front cover are as follows:

10 degrees @ 800 rpm
18 degrees @ 1500 rpm
23 degrees @ 2000 rpm
26 degrees @ 2500 rpm

I find the figures quoted in the manual rather confusing so I wondered if the figures above are ok or are they too advanced?
As an aside, with the dizzy in situ is it possible to see the type number on the casing?
Also, generally speaking is it better to have more advance than retard as regards the engine running hotter in temperature?
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PostPost by: oldelanman » Sun Sep 19, 2021 3:09 pm

As an aside, with the dizzy in situ is it possible to see the type number on the casing?


Should be possible with the aid of a mirror or camera phone.

Distributor (a).JPG and
Type number and date
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PostPost by: William2 » Sun Sep 19, 2021 5:07 pm

Just tried using a mirror and have verified it's a 41189 type.
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PostPost by: Andy8421 » Mon Sep 20, 2021 10:13 am

William,

I notice you are in West Sussex. Did you get to Goodwood over the weekend?

Back on topic, read through the following thread, it may help. It explains the errors in published material, confusion over crank vs distributor rpm, and then comes up with suggested curves for a 41189 distributor.

https://lotuselan.net/forums/viewtopic.php?f=31&t=47025

I hope it helps.
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PostPost by: steve lyle » Mon Sep 20, 2021 6:58 pm

Maybe you’re an expert in distributors, and have a set of springs and the equipment needed to set a curve. If so, ignore this.

If not, really the most important thing is to get the max advance at about 3500 rpm or so. By max, I mean the most possible without preignition. This is likely about 32-35 degrees of crank advance.

So what I do is set it at 32 at 3500, go climb a hill at WOT. If it pings, back it off a bit and try again. If not, and you want optimum power, advance it a bit and retry. Stop when you’re happy and not pinging.

Then, if you don’t like the curve (i.e., acceleration is not smooth), pull the dizzy and take it to a shop that knows what it’s doing. In the states, Advanced Distributors would be a good one.
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PostPost by: William2 » Tue Sep 21, 2021 9:26 am

Andy, thanks for your reply. Yes I went to the Revival on the friday and took my Elan. Have posted pictures under Lotus Discussions.
Set the ignition timing to 10 degrees below 1000rpm and checked advance settings up to 3000rpm and they seemed about right.
Car pulls well with no sign of pinking or running on,
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