MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Distributors: 123 vs. CSI - which is better?

Hi guys,

I'm looking at this year's upgrade and I've decided on getting a new distributor. I've got an old 45D fitted and it's time to replace it.

I'm after a programable one as my engine isn't stock, and I see that that gives me the option of the 123Tune and the CSI Pro (not interested in Bluetooth, happy with a USB cable connection).

Both seem similar in spec and similar price (although it's an extra £50 for the USB cable for the CSI from Moss).

Just wondering if there's any evidence (or opinion) on what is better / more reliable / easier to program?

Many thanks in advance,

Grant :-)
G Hudson

Grant,
I'm not sure the CSI has been about long enough for many owners (and garages?) to have done comparisons. Someone who's got a 123 probably wouldn't have reached a point were they needed or wanted to change it.

Then there's personal likes or dislikes. 123 wasn't alway the most commutative going back to when I got mine about 12 years ago so some wouldn't like that and remember that so may prefer to recommend or try CSI instead.

Also previously you had to take the standard 123 out to adjust the curve setting, I believe that's no longer the case.

On my Midget I've had a standard 123 fitted for 12 years and it really is fit and forget, only downside to me is that it uses Bosch (Beru) cap and rotor and on mine the fat spark can chew the cap terminals so they need checking/servicing annually.

My car's engine and other bits are, modestly, off stock so when a mate and I fitted the (standard) 123 I asked if we should try the higher settings and he laughed. I've had my Midget on Peter Burgess's rollers a number of times (and Peter used to be a 123 agent) and he's never suggested changing the setting (but at least he didn't laugh at my suggestion).

So are you sure you need the additional hassle of messing around with additional programs and programing with independant off board computers with their additional running programs that never go wrong or play up, (do they). Could you perhaps go with the fit and forget standard dissy with one of the in-built settings, set it up on with a knowledgeable tuner to MGB (Peter literally wrote the book) on the rollers (Peter's charge is extremely reasonable and he does a great job) - then forget about it, drive the car to get the benefit.

My Midget has an unknown higher lift cam, modest head work, no engine cooling fan, tubular exhaust manifold and single box exhaust, K&Ns, 4-Life, Millers Classic Sport High Performance oil, sports coil, high quality HT leads, slightly wider gapped NGK plugs - and standard 123.

I've only put above to give an idea of the modest upgrades engine wise.

I've seen CSI for the Sprigets at least had settings by a Mini expert but no idea about for MGB.

Moss are not the only suppliers of parts for our cars.

HTH.
Nigel Atkins

I have a standard 16 curve CSI fitted to my 1275 Midget and have had no problems, in fact I am very impressed. As a result I recently fitted one to my BGT but have not had a chance to really try it yet, apart from the odd local run.

The CSI was recommended to me by an ex Downton trained tuner, mainly I think because on a midget it was easier to change the curves given where the distributor is and he was going to tune it! It may be similar on a B, but as you will be using USB probably not an issue?

As I have not used a 123 I cannot compare them. One of the attractions of the CSI to me, in addition to the ease changing curves, was the more standard look including use of a Lucas style black cap.

Customer support has been excellent. Wim replied to my queries very quickly, normally the same working day so no problems there.
Mike Dixon

I get the feeling CSI may have learnt from the early customer service of 123ignition's one bloke(?) (Albertronic BV) set up, customer support, information and contact used to be via a Forum. I see there still is a forum but it looks different and probably my posts on rotor and cap cross-reference numbers are archived (or dumped/lost/deleted/redundant-technology-website).

I noticed when CSI first started that they are from The Netherlands same as 123ignition I don't know what the significance is, if any, but seems too much of a coincidence to be totally unrelated, but it might be.

If I was buying a standard CSI or standard 123 now I think I'd go with the CSI for Lucas type cap and rotor, but I've been very pleased with my 123.

Obviously I don't know if the CSI would be better, on my Midget without being able to drop one in and tune on the rollers to compare results, but much more importantly than paper numbers the difference in real life driving (only on the roads for me).

Nigel Atkins

I've no experience of the CSI, but I have a 123-Tune on my BGT V8. The ignition curve is infinitely adjustable through your laptop, both the advance settings and the vacuum settings. It was easy to construct a nice looking "mechanical" advance curve, but I hadn't a squiz what to do with the vacuum settings so I just bunged in something that I thought might be right and it runs like a dream. I think the lazy 3.9 V8 is very tolerant of being a bit mistimed. Just as well really.
Mike Howlett

Hi all,

thanks for your feedback. As it's a reasonable layout cash-wise, I'll probably go for the 123 as it's more proven.

cheers,

Grant :-)
G Hudson

My friend has a moderately tuned GT (big valve head, HS6 carbs, sports exhaust but standard cam)pretty much the rally 1800S land crab specification. His engine was a bitser and had 45D distributor. Having read Peter Burgess's book and his adverse comments about the 45D advance curves (vacuum and mechanical) my friend opted for a fully electronic disi. Peter says that the 25D advance curve 40897 was suitable for all but the highest states of tune. We selected the 123 but not the programmable type and set to curve 2. This proved to give a very good result in terms of drivability, performance and economy.
I don't know why anyone would go for a programmable distributor. It would take many weeks of test bed time to do an ignition map across all speed and load conditions. The best you can hope for is to get it done at full load. I'm a firm believer in the vacuum advance because that takes care of the load sensitivity whilst the centrifugal advance does the speed sensitivity.(OK at wide open throttle there is no vacuum). Once you build a none standard engine then the factory advance curves are unlikely to be perfect for your engine but Peter seems to think they are good enough.
Paul Hollingworth

Grant,
Paul has confirmed what I was going to suggest, to save more time and hassle by going with a standard 123. And unless for any reason Peter changed that the advance curve 40897 was suitable for all but the highest states of tune in his update of his book there you have it.

John Twist said the earlier settings were better running, presumably before they had to change them for greater emissions scrutiny.

As Mike and Paul has put getting your custom settings can be awkward and very time consuming and to get them nearer to best takes knowledge and usually more equipment. With or without tuneable dissy the racing boys can spend hours on the rollers to get initial settings and then return with road/race running experience for tweaks or adjustments for different events/environments.

In the old days of chipping the car would be driven for hours with the chip tuner making all kinds of readings and adjustments but if he narrowed the parameters too much the settings could eat into the the car components' tolerance margins too much or simply be wrong for others driving conditions (or even driver depending on how far it's taken).

The 45D you had probably wasn't totally consistent as even with full servicing and set up attention, which most didn't get over decades of use, abuse and wear, the bottom ends tended to out of spec a few years after the car left the factory. So just fitting the new fully electronic consistent dissy will give improvement but also very likely means possible adjustments to timing, plugs and carbs set up for greater improvements.

Unless your car is highly tuned and/or you have the time and knowledge or money to pay someone else setting up a tuneable one to get bigger improvements ain't as easy as some make out. A rolling road session for tune or non-tuneable will help but the difference between the two might not be as great as you think, depending on your car of course.
Nigel Atkins

Grant,
I meant to put, whatever you decide it'd be good to get your feedback, what you decided, whether you found improvement (or not) and whether the improvement was worth it. Obviously it might take a bit of using the car to find consistent improvement in starting, idle and response through the rev range and driving.

I think often any mpg gain is lost because the improved performance encourages more spirited driving, which is what these cars were designed for.
Nigel Atkins

I had my MGA on Peter Burgess's dyno last year after he had re-ported the cylinder head and fitted stronger valve springs on my 5-brg 1950cc engine.

His latest software on the dyno detected what he called "detonation events" in my engine in the higher rev ranges. He retarded the ignition and this solved the detonation but dropped the bhp figure at the top end by about 7 bhp.
Fortunately, there was a corresponding similar increase in bhp in the lower rev band which is very obvious when you drive the car and overall, the car felt quicker.

Peter suggested that this suggests that the advance curve in my "Race distributor" doesn't suit the the engine and that a programmable 123 distributor could be set up on the dyno to give better results.

So maybe I should put the programmable 123 dizzy onto my Christmas list. :^)

Here's a link to a write up of my first visit to Peters dyno to get the engine set up.
(On since checking the dyno report, the bhp figure was actually just under 140 bhp)

http://mgaguru.com/mgtech/power/pp201e.htm

Cheers
Colyn

Colyn Firth

Just to clarify, I went for the fully programmable 123-Tune for my V8 for the simple reason that they didn't make any other type for that engine. It wasn't because I'm an ignition wizard - far from it. It would be hard to get the optimum settings without recourse to a dyno, but as I said, the Rover V8 seems very tolerant of ignition timing.
Mike Howlett

This thread was discussed between 20/04/2021 and 22/04/2021

MG MGB Technical index

This thread is from the archives. Join the live MG MGB Technical BBS now