Is a vacuum pipe needed on a 123 distributor?

[PaulB]

Hi
I've just replaced my distributor with a 123 tune distributor. Before I had my vacuum pipe removed as I was told it was not needed on my set up of K&N air filters with stub stacks.

However, now I've got a programmable 123 distributor fitted should I refit my vacuum pipe before going to a rolling road to get it set up?

Thanks

[Bainzy]

Yes, the previous information you received about it being not needed was incorrect. It gives you extra advance on cruise conditions, which enhances fuel economy and is very much worth having.

[Gt6s]

1381 wrote:

Yes, the previous information you received about it being not needed was incorrect. It gives you extra advance on cruise conditions, which enhances fuel economy and is very much worth having.

Agreed you deffo need it conected on the programable version.

[PaulB]

Thanks guys, will reconnect it tonight. Cars booked in on Friday for rolling road tune.
Can't wait to see what the difference will be once she has been properly set up.

[Saltddirk]

Hi,
Please keep us posted on the results,
I have bought one months ago but still waiting to install it.....

dirk

[PaulB]

2053 wrote:

Hi,
Please keep us posted on the results,
I have bought one months ago but still waiting to install it.....

dirk

Will do. Shes booked in for tomorrow.
It doesn't take long to fit. It took me about 90 mins but I was also cooking chicken on a BBQ as well.
Probably less than 1 hour to fit. Even without the tune she is running better now.

[PaulB]

Took her in for a rolling road tune.
At the begining she was only producing just over 50 BHP at the end she was producing 70BHP!
Although this wasn't down to the distributor programming. It was spot on at the beginning so didn't need any adjustment. The adjustments were all made to the SU carbs and especially the needles.
As you can imagine the difference is brilliant. Car revs alot smoother and has a lot more pull mid range and at motorway speeds.
Very Happy :-)

[FloydP]

Hi Paul,
I wouldn't mind an extra 20bhp myself, whereabouts did you take it in the end?
Cheers,
Floyd.

[shedmonkey]

PaulB wrote:

Took her in for a rolling road tune.
At the begining she was only producing just over 50 BHP at the end she was producing 70BHP!
Although this wasn't down to the distributor programming. It was spot on at the beginning so didn't need any adjustment. The adjustments were all made to the SU carbs and especially the needles.
As you can imagine the difference is brilliant. Car revs alot smoother and has a lot more pull mid range and at motorway speeds.
Very Happy :-)

Which needles did you use in the end?
Its great when you see results at the rolling road ! I was well chuffed with the torque improvements I made using my home comedy air box!

[CharliesStag]

As said, on a daily car it is required for MPG.  Race car drivers tend not to use the vacuum advance since MPG is not of major concern (well, they will not be on part throttle where vacuum advance comes into play) but also it is to do with more of a failsafe matter on some distributors (I.e if the baseplates slip off the vacuum part etc. it could end up costing an engine).

I too am interested in what needles you have, in addition to the spec of your engine.

FWIW to any owner if your car is a keeper I can definitely recommend a 123 Ignition distributor.  A friend of mine put one into his Dolomite 1850 (by having his existing distributor redone being an AC Delco type).  I must say that it drives like a different car.  It pulls better than an 1850 has the right to from the bottom end right to the top (dare I say it, not much worse than his Sprint did).  But then again I have always throught a good new distributor can transform a car over a tired unit with an iffy advance mechanism (sticking, or simply tired).

I have always considered getting one but I never seem to keep a car long enough.

[shedmonkey]

Agree with all the above a 123 completely sorted the TAXI - 2.5 pi engine running on carbs but again a new dizzy on the spit with decent elecy ignition (couldn't afford another 123!) sorted it -ran like a different car

[PaulB]

FloydP wrote:

Hi Paul,
I wouldn't mind an extra 20bhp myself, whereabouts did you take it in the end?
Cheers,
Floyd.

I took her to ATSpeed Racing in Rayleigh. A father & son business. The father did the tuning on my car as he know SU carbs well. He once worked at an old Triumph, Jaguar, Rover dealership. They were recommended by another club triumph member on this forum.

Their website address is: http://www.atspeedracing.co.uk/

[PaulB]

ajp wrote:

Which needles did you use in the end?
Its great when you see results at the rolling road ! I was well chuffed with the torque improvements I made using my home comedy air box!

After sorting out a sticking choke on my carbs, he proceeded to adjust the needles.
He used my existing needles but filed them to give the right mixture at mid range and high range. Apparently it was too lean at high speeds.

[Dannyb]

How long was it on the rolling road for. Do you know what needles you have fitted.

[shedmonkey]

PaulB wrote:

After sorting out a sticking choke on my carbs, he proceeded to adjust the needles.
He used my existing needles but filed them to give the right mixture at mid range and high range. Apparently it was too lean at high speeds.

Ah sounds about right ,take it you are running K+N style filters and a bigger exhaust? any head mods? think you might now have a profile similar to the AAT Needle? http://www.mintylamb.co.uk/suneedle/

[thebrookster]

Ahh, now that is interesting!!

I had wondered from reading his website (through your link), and from what you have just said confirms it, they actually do custom needles for your car!!

I am impressed, to say the least. Far easier by half than trying to select a profile, just dump it on a rolling road, presumably with O2 sensor in the exhaust, and grind an exact needle to what you need. And not only that, he doesn't need to carry a large stock of needles, simply some basic ones that can be modified. I like it.

From that, I have to say that this guy is worth keeping in mind, there are not many people capable of simply making a correct needle profile these days!! (Look at the issues big Chris had with carbs, trying to pick the correct profile!!). The information for this is out there, but you rarely hear of people who can actually put the theory into practice now, and those who can are the old-timers, most of whom have retired.

Cheers Paul!!

Phil

[Bainzy]

If I had a rolling road, calibrating SU needles to give perfect fuelling for any engine setup would be p*** easy in combination with the wideband o2. The problem is if you can't put a load on the engine, when you're in your garage you're hitting 4000rpm and you've not even got past needle position 5 on the calibrated rods in the dashpots.

[piman]

Hello Bainzy,

David Vizard's poor man's dynamometer was to  jack up the back of the car and put it securely on stands. Use the car's brakes to load the engine. Takes some time as you need to let them cool down from time to time. I  must say I haven't tried it but it's a thought?

Phil,
Kas Kastner has a picture of his needle lathe in one of his books. Simply a Dremel style drill clamped to a base board, a fine file, a micrometer and ruler to measure the profile.

Alec

[PaulB]

I don't know what needles I had fitted originally. I've got K&N filters, stub stacks, sports exhaust and manifold and a standard unleaded head. Rest of the engine is standard.
Also apparently it was mainly running on the back carb up to 30mph. So he had to balance the carbs as well.
I was there for  nearly 3 hours. It took longer than normal because the guy would adjust the needle, refit it, check the power range and then repeat the process until it was perfect.
Very happy with the results. Although kind of wished I saved some money and went for a regular 123 Distributor as I haven't taken advantage of its programmable features.

[CharliesStag]

I guess you never know when you may end up tuning your engine though ;).

[Gt6s]

PaulB wrote:

Although kind of wished I saved some money and went for a regular 123 Distributor as I haven't taken advantage of its programmable features.

Then get your laptop out and have a play.

[thebrookster]

piman wrote:

Phil,
Kas Kastner has a picture of his needle lathe in one of his books. Simply a Dremel style drill clamped to a base board, a fine file, a micrometer and ruler to measure the profile.

Alec

Hi Alec,
my comment was not so much aimed at saying this was not possible (I have another book by Des Hammil that goes into quite some detail about modifying needles), what I was trying to say is that there is a big difference between theory and practice.

Sure, I can modify needles with a bit of care and attention, as no doubt can several others on here, but to be able to complete two needles identically, along with doing the initial settings, in one day is in my book definitely skill!!

Cheers,

Phil

[piman]

Hello Phil,

I was trying to show that it doesn't need a highly technical bit of equipment to do this job. Certainly some basic engineering skills and tools are necessary, and a lot of patience. I would also expect one or two failures early on but I don't think that it is too difficult to make two or three needles to match each other with a little practice.

Alec  

[Nick Jones]

As regards getting the best out of your 123, I reckon that although the full throttle settings will have been well checked on the RR (and this is the very best way to check them), you may have some scope for adding more advance at cruise and low load settings which will help economy and sharpen up throttle response - what you are effectively doing here is tweaking the vacuum advance.  This is actually best done on the road, driving around with a suitably savvy passenger working the laptop.  I've not had any dealings with fully the mappable 123, but if the Megajolt/'squirt experience is anything to go by, 30 minutes driving about can make a huge difference.

Nick

[shedmonkey]

Talking about father and son rolling road gurus remember Downton Enginering  well Richard Miles and his son have a rolling road at Tipton Garage http://www.tiptongarage.co.uk  great characters never- laugh at my sheds!-and always help me get the most of what little I have ! -they will make their own needles they also make there own ram pipes and tune them to suit applications in fact they will make you pretty much anything including inlet manifolds etc

On another note its always a good idea to balance the carbs the best you can before taking to the rolling road as it cuts down the time you get billed for I get laughed at balancing them with a length of pipe but have got pretty good at it doing it that way and even got complimented a few weeks ago when I took the spit in on how well I had done it just with a bit of pipe! it shows that with a bit of patience you can achieve what you may feel to be "black art stuff"