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Help with 123 ignition advance curve.


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Hello all,

 I wonder if you could help me out?

I have a 1971 TVR Vixen fitted with the Triumph TR6 Engine, in what I think would have been US spec. It has had the original carbs replaced with two SU HS6 and was fitted with an uprated cam a number of years ago. In the engine rebuild invoices it states Triumph 6 Cyl sports "R" cam kit.  Having an uneducated guess I think it is could be a  Kent TH5-6 (fast road).

 I was having intermittent ignition problems so I decided to fit a 123 ignition kit and wondered if anyone has any experience or could help with a suitable curve for me to apply. 

 Many thanks in advance

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Stan,

I am just getting to grips with the app that controls the timing. I will try to have a better look tomorrow. It seems you can programme a curve with the ignition on but the engine not running. You can then fine tune while on a test drive with a tune up/tune down button. 

I am going to set the curve as Jochems recommended and try that. After fitting the new 123 distributor I set it close to what was in the Haynes manual but it felt a little less perky than before in certain parts of the rev range. I used the tune up and down buttons but thought I would try a different curve then fine tune it from there. This is all subject to a bit of guesswork as I am not 100% sure of the cam profile etc. Also, I am sure the old distributor was far from perfect, so adjustments will have been made over the years, not to mention the difference in fuel compared to when the original curve was published. I will be tweaking for a while to come. 

 

 

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I have the 123tune+ bluetooth version on my 6, very happy with it.

to set the initial curve i measured the curve of the old distributor and set the new one up the same.

i measured by callibrating tdc, was 8 degrees out so needed a new crank pulley!, then measuring advance every 500 revs.

the 123 app works well on iphone but is unreliable on android

i could dig out the curve if it would help?

steve

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I didn't know it did that - sense the temperature of the engine. Presumably through the physical connection to the block. Is this just a Tune feature? I'm guessing the base model 123 (which I have) doesn't do this? I've no idea why you might want the ignition to respond to temperature, I'm just impressed that it does.

Merry Xmas everyone, Richard

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Steve, 

 If you could dig out your curve it might be a help. I will be trying the figures Jochems posted above but if I have another one to test it would be good.

Richard,

 Yes the info you can see on the app is good and I also like the fact you can use the app to immobilise the car which is a useful feature.

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c rap. Now I want a new 123 dizzy with bluetooth. Interesting feature to "lock" it so that the car wont start. Easier than removing the rotor arm. Better change that default password though.

Stan

Edited by foster461
defeat the stupid cencorship.
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Ok i’ll look out the numbers tomorrow

just checked the app and it doesnt remember the numbers when its not connected to the car!

steve

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1 hour ago, Steves_TR6 said:

Ok i’ll look out the numbers tomorrow

just checked the app and it doesnt remember the numbers when its not connected to the car!

steve

Yes, I noticed that. It took a while to get the hang of the app but I am finding my way around now. If you wouldn't mind, could you have a look at the vacuum or MAP curve while you are connected, it would be appreciated.

I put in a new advance curve with Jochems figures today and it seems to be pulling well now but if I have another set of figures I would like to compare and see which suits best.

Thanks again.

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Unless you have a dyno bench, you will not find much difference within few degrees. TR6 engine is very forgiving. 

Do the following:

put in 3rd. Start at 1.500 rpm, pull upto to 4.000 or 4.500. use stopwatch. Repeat. 

MAP feature not needed. 

Program 2nd curve and use switch in the console. Play between the two curves. But trust me, after few weeks, you are done playing....

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Hi out there, I would like to tell you a funny story.

A friend of mine, TR4A owner as me, drove his car as it was for years (for example to Scotland) and has always been pleased.

Indeed his car run very well, what I had to realise when we went out with him ( and our wifes) in our TRs, short and also long distances.

 On my recommendation he bought a ignition gun, the same type I own, but the gun failed on his TR when he used it.

But mine also failed on his car, both showed 22 degree on every rev, but both guns worked well on my car.

Problem was found and repaired: his distributor was clued by oil, rust and dust in one position and did not work for years!

I guess not only the 6 cylinder is very forgivable...

Funny story, isn't it?

Ciao/ Cheers Marco 

 

Edited by Z320
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Ok so the advance values on my ‘mongrel’ pi car were/are

tickover 8

1000 9

1500 10

2000 14

2500 18

3000 20

3500 22

4000 28

i plan to have the mu and ignition set up on a rolling road, i think it would take a little more advance, but runs well on those numbers

steve

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  • 1 month later...

I tried a few different curves but found that the figures Jochems quotes above really suit my car. It feels responsive and perky. I think it might be giving slightly less MPG, but that isn't based on anything scientific and is negligible. I am happy with the set up and if any slight improvements could be made it would have to be on a rolling road, but I don't feel the need to tweak it any further.

 

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  • 1 year later...
On 12/25/2018 at 4:13 PM, JochemsTR said:

if you are close to a CR 9.5 or even 10 try a curve close to this

 500 - 12°

1000 - 16°

1600 - 21°

2000 - 23°

2600 - 28°

3000 - 30°

4000 - 30°

 

Hi Jochem, what have you set on the retard tune settings, so basically the MAP curve? I've just installed the 123 tune+ and have to try out now the best curve. The car is running, however I've to try some curves to find the best setting, as it's running on idle a bit unsteady. As I'm new to this topic i wonder how to handle the MAP curve...

Many thanks!

Albert

Edited by Maverick
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Hi all,

Do these numbers include the static advance?

Tim

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Hi Jochem,

just for my understanding: 

Setup for a standard CR with contact breakers means 10 degrees static and 26 degrees centrifugal (13 degrees in distributor), so 36 degrees max.

The 123 Ignition manual (PDF by Limora) says to turn the crankshaft to the required static timing (that would be 10 degrees) an turn the distributor till the led lights. This would mean that static timing plus the curve in the distributor are added? Or am I misunderstanding something?

Regards Peter.

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3 hours ago, JochemsTR said:

Hello Albert, on my previous setup which was with 123Tune and carburators, I did not use MAP. Just the curve as I mentioned...

Jochem

thanks Jochem, very much appreciated. I was testing today with the exact numbers you mentioned without the use of the MAP and it's really running very nice!

The starting is much faster and softer. I still have to work on my idle RPM, currently it's running on 1.100 RPM on idle, a bit high maybe... but RPMs below that my TR250 do not like yet. Have to fix the carbs as well at some point and idle them probably. Unfortunately I don't know which camshaft i have inside, i guess it's a Kenwell 280°.

Could this be the reason for the high idle RPM?

Edited by Maverick
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In my current EFI config, I am running 10-11° advance (@ idle, 900). There is lots of debate whether this may be too less for a 143 HP PI Engine. For my 170 HP and CR 9,5 it has suited me.

The curve I presented with my previous 123 config, is indeed higher. about 15° @ Idle 900. This seems to be the value for best torque in lower RPM....and yes, it includes static advance. These are the numbers you see using a strobe light. with a max. 30-32° depending on CR and engine config.

If you do not have a rolling road, I mentioned following test:

put in 3rd. Start at 1.500 rpm, pull upto to 4.000 or 4.500. use stopwatch. Repeat. Increase curve with 2 degrees increments. When indeed pinging occurs, back off 2 degrees in higher RPM range. 

Jochem

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