123 Ignition advance curves - whats your setting?

[Encom]

Looking to gather together peoples settings for the 123 Ignition distributors to help narrow down what is a good initial setting - so the more the merrier

I have one fitted to my standard Mk1 Vitesse 2 Litre set to curve 0, running 98 Octane.

Anyone else?

[piman]

Hello Encom,

a good start is to try and match the original distributor curve as the manual gives.

Alec

[Encom]

Yeh I plotted all the 123 curves and the factory curves for various 6 cylinder engines in MS exel, and there was no clear winner. So reverted to 'seat of the pants' tuning.

I found in my green Vitesse that the Delco dizzy with points had way better performance than the 123 on all the curves I tired (without getting too carried away with advance at higher revs).

I'm wondering if the 123 with the USB programmable port might be a better bet to match the factory curve.

[Tim Bancroft]

James Shackford is using the programmable 123 in his 2.5Pi and is very pleased.

I have a 123 in the saloon and am running 0 as like you I cannot find a match.

Have a 123 for the spittie, about to plug that in next week.

[Nick Jones]

My opinion is that the fully programmable 123 is the ONLY one to consider.

I also agree with Alec that for a standardish engine at least, matching the original mechanical distributor advance curve will get you 90% there for the full throttle curve.  The vacuum side is trickier as you've got so much more control with a programmable system you can do things the Triumph engineers could only dream about.

Nick

[James]

I made this ages ago

[Encom]

Cheers, just to be clear the advance curves shown in the 123 instructions are total advance ie: static + advance from the selected curve?

[Encom]

Okay, I think I've cracked. From the work shop manual and using Minty's page (cheers, very handy 🙂 ) I came up with the table below. From this curve 6 or 7 should be sweet - but (there always a but), having tried these settings out this afternoon, I have been getting 'pinking' in the mid range.

After a bit of digging around, found the front carb wouldn't increase engine speed and drop back when the lift rod was used to lift the piston - it did a few days ago = air leak!! just got to find it now.

[piman]

Hello Encom,

the Delco and Lucas have quite different curves, which is correct for your engine?

Looking at the 123 curves it seems that none come close to to either of the mechanical distributors at one setting, or am I misreading the graph?
What do you do for the vacuum advance as your engine fuelling is tuned to use it?

Alec

[Encom]

Yes, I know what you mean, none of them are particularly great. The dark orange cells on the right indicate the best match at the RPM for the Lucas 22D6, so it was a case of picking the curve that had the most orange cells and came closest on the other cells.

The car came with a Lucas 22D6 fitted, but my earlier had a Delco 204 (which went really well), and whose 1968 production date was only weeks earlier. Bearing in mind both cars are NZ assembled.

I have excluded vac advance from it as this varies with throttle position ie: wide open throttle very little vacuum, but mostly likely mid range to max RPM, and hence cent advance.

Fueling wise need to find that pesky carb leak that has developed, and then try again. I'll most likely end up fitting a bung to the exhaust and using a digital AF meter fine tune it, then punt for a 123 Tune. The standard 123 just isn't close enough, better off with a set of points.


  

[piman]

Hello Encom,

due to the large discrepancy between the Delco and the Lucas, are you sure it is correct for your engine. If you have a workshop manual you should be able to check what version of the 22D6 you should have fitted, there is a 5 or 6 digit rference stamped on the side of the distributor to identify it.

Alec

[Encom]

Alec, the model number matches with correct item for the high compression engine I have; but I don't have a specific build sheet for this car. So it could have been changed over at some stage.

I can't understand why two cars that were built only weeks apart would have two completely different advance curves, for what is suppose to be the same engine.

Even the brake master cylinders are different, one was the large aluminum res, and the other small one with plastic extension to the res.

[RogerD]

Hello Encom! I have a 1966 Vitesse MkI 2-Litre with Lucas 22D distributor, and I have finally decided to invest in a 123 distributor. How has the 123 worked for you, are you pleased with the performance? Which setting did you finally choose? Anyone else out there that has some experience of a 123 distributor in a Vitesse MkI? (or same 2-lite engine?)
Regards,
Roger.

[Nick Moore]

Hi Roger,
I just fitted a 123-tune distributor to my Herald. The 'tune version allows you to program your own advance curves. I looked at the normal 123 as well, but decided that it was unlikely that any of the 16 curves provided would be perfect for my engine. I started with a Spitfire's advance curves, and adjusted them during road testing. In the long run I may set it up with two curves, one for 91 octane fuel and the other for 98. Switching between them is as simple as flicking a switch.

Installation took about an hour.

[Deleted User]

Gents

John Harris - Newbie. 1980 1500 spitfire, standard, K&N's extractor manifold.

123 ignition tune, starting point Rick B and the attached file. See Spitfire 41449 work sheet. In the following post I have put my curve and what I did.

John

[Deleted User]

Gents

Following on from the previous post.

A couple of things I would add. I went to a lot of trouble to ensure TDC was detected properly and marked up on the timing marks. I fitted the 123 Tune, set the green light and then started the car. I then re timed the ignition at 2000 RPM with a professional strobe so that I could be absolutely sure that timing was accurate and only needed to line up with the TDC mark ( The strobe could have advance dialled into it ). I then checked the rest of the curve, which was too. I did not attempt to set the 123 dynamicly at 800 RPM - too erratic to be confident.

The cars pulls great from low down and goes like a rocket above 2500 rpm. I might yet add one degree to each of 2600, 3200 and 4100.

Carbs fully balance with a professional flow meter .. etc. Lucas sports coil, plug gaps still at 25 Thou.

I hope it helps others.

One other note - I have just had some thrust buttons manufactured in UHMW to Paul Geithner's specification to fit to a new rear spring - I will report in the relevant section as to how I get on.

Picture of the curve attached.

John