electrical and ignition 123 Ignition Distributor....any Info Or Personal Experience?

[antares242]

7 hours ago, '76mintgrün'02 said:

That sounds like good progress.  I miss peterschop.  He went away a few years ago.

 

It seems like you might have more advance than needed up top, but idling with ten seems appropriate.  Some people advocate even more at idle for dual carbs.  

 

I've recently read that the vacuum feed for the 123 should come from a ported vacuum source (before the throttle plates).  I've never seen a situation where someone's done that with DCOEs. 

 

I think Peter had a downdraft Weber (same as mine = 32/36) and they have a ported vacuum nipple.  Manifold vacuum behaves quite differently.  Especially at idle.  So, you are probably pulling in more advance at idle using manifold vacuum.  I don't really understand how the MAP curves work though.

 

I did install a vacuum gauge in my console, so I can see when the vacuum pod is pulling in more advance.  You could tee off of one of your lines and do the same thing, if you are curious about when/how much it is adding advance.

Tom

Thanks Tom, you’ve been tremendously helpful. I honestly don’t know what “after” or “before” the throttle plates mean. Based on my setup (see below) can you tell me if these ports are in fact after the throttle plates? Does that mean the path i should follow in order to determine if they’re after is going from the cylinders out to the air intakes or is it the other way around? Another thing i was reading is that based on my compression 9.5:1 i should need less advance? So far with the above curve and some tweaks on my carbs this morning the car seems to run pretty good. But I’m new to this world and I’d like to squeeze the best out or it! Thanks again for all the help from you guys.

 

['76mintgrün'02]

I know very little about side draft carburetors, but it looks like your vacuum line is installed after the throttle plates.  Or, behind them, as the air enters the carburetor.   Yours look like they are practically on top of the throttle shafts, so it might depend on how they are drilled, as to which side of the plates they are on.

 

On my down draft Weber, there is a nipple above the plates (before) and then one below that on the manifold, so it is obvious/common knowledge which is which.

 

Too much advance is bad.  Too little and it generates extra heat in the head.  There is a tendency to assume "more is better", but more is potentially dangerous.  Without a dynamometer, I don't think you can really "squeeze the last bit of power out of it".  I'd suggest keeping it in the "safe zone" and having max advance more like 36 degrees.  I have 38, but I also have a lower compression (tired) '76 engine. 

 

I'll bet this stuff has been discussed in the previous 25 pages of this thread.

 

I like helping when I can, but my knowledge is limited.  

 

Tom

 

 

Edited August 15, 2021 by '76mintgrün'02

[antares242]

WOW guys, today I was finally able to test my car at highway speeds and it’s a NIGHT and DAY difference. Even with what looks to be a very basic curve the car has the low end torque it had lost way before, acceleration is way smoother and drama free and idle is extremely smooth and stable once operating temperature is reached.

Tom, thanks for your advice, tomorrow I’ll play it safe and go down a couple degrees, leaving it at 36 and see how it takes it. For now I’m really happy and thankful for all of you guy’s guidance! Stay safe y’all. 

[man_mark_7]

16 hours ago, antares242 said:

Thanks Tom, you’ve been tremendously helpful. I honestly don’t know what “after” or “before” the throttle plates mean. Based on my setup (see below) can you tell me if these ports are in fact after the throttle plates? Does that mean the path i should follow in order to determine if they’re after is going from the cylinders out to the air intakes or is it the other way around? Another thing i was reading is that based on my compression 9.5:1 i should need less advance? So far with the above curve and some tweaks on my carbs this morning the car seems to run pretty good. But I’m new to this world and I’d like to squeeze the best out or it! Thanks again for all the help from you guys.

 

 

 

I am no expert, but I ended up running my dual Webers / 123 without any vacuum advance at all. I think that unless you have some kind of one way check valves in those lines running from your carbs to the dizzy all you are doing is kind of diminishing the vacuum in any one carb throat. I'm not sure what each adjacent cylinder is doing at any given time, but certainly while one is on an intake stroke the adjacent one could be on compression, ignition or exhaust meaning the adjacent carb throat is at nearly(?) atmospheric pressure. In this case all the crossover tube is doing is damping the vacuum for the throat that is on an intake stroke.

 

How does the vacuum signal on the 123 look? I think they use a pretty heavily damped signal so it might appear relatively stable - this might be OK? It would be interesting if you stuck a fast reading vacuum gauge at the end of your vacuum line and see how much it fluctuates. 

 

It would also be interesting if you capped off each vacuum tap at each of the 4 carb throats and went for a few runs. 

 

Good luck!

[Carlos_M]

12 minutes ago, man_mark_7 said:

I am no expert, but I ended up running my dual Webers / 123 without any vacuum advance at all. I think that unless you have some kind of one way check valves in those lines running from your carbs to the dizzy all you are doing is kind of diminishing the vacuum in any one carb throat. I'm not sure what each adjacent cylinder is doing at any given time, but certainly while one is on an intake stroke the adjacent one could be on compression, ignition or exhaust meaning the adjacent carb throat is at nearly(?) atmospheric pressure. In this case all the crossover tube is doing is damping the vacuum for the throat that is on an intake stroke.

 

How does the vacuum signal on the 123 look? I think they use a pretty heavily damped signal so it might appear relatively stable - this might be OK? It would be interesting if you stuck a fast reading vacuum gauge at the end of your vacuum line and see how much it fluctuates. 

 

It would also be interesting if you capped off each vacuum tap at each of the 4 carb throats and went for a few runs. 

 

Good luck!

Can you share what curve you’re using?  I’m running mine without vacuum as well and would love to compare. 
 

thanks!

[Steve76063]

On 8/14/2021 at 5:25 PM, antares242 said:

Thanks Tom, you’ve been tremendously helpful. I honestly don’t know what “after” or “before” the throttle plates mean. Based on my setup (see below) can you tell me if these ports are in fact after the throttle plates? Does that mean the path i should follow in order to determine if they’re after is going from the cylinders out to the air intakes or is it the other way around? Another thing i was reading is that based on my compression 9.5:1 i should need less advance? So far with the above curve and some tweaks on my carbs this morning the car seems to run pretty good. But I’m new to this world and I’d like to squeeze the best out or it! Thanks again for all the help from you guys.

 

It looks like your vacuum hoses are tie-wrapped to the throttle linkage shaft?  Wouldn't that make them 'move' when the throttle is actuated (unless the tie-wraps are 'loose')?

[fastricky]

Hi all, I could use some help - I currently have a 123 Dizzy in my tii, however it is the early version that isn't programmable, it just has the presets you select based on your car. 

 

The car runs wonderfully as is to a point: It revs turbine smooth up to 4000rpm, but from 4k to 5k it gets rougher and above 6k is trashy. I bought the programmable version and will be installing it soon and am hoping I can program various advance to have the same smoothness throughout the rev range. 

 

Any thoughts? As well, is there a cheat sheet I can refer to to plug in the right curves etc (I don't live at any elevation). Thanks all - Rich 

Edited June 8, 2023 by fastricky

[Mark92131]

On 6/7/2023 at 6:14 PM, fastricky said:

Any thoughts? As well, is there a cheat sheet I can refer to to plug in the right curves etc (I don't live at any elevation).

 

You could try some of Tii advance curves from the Blue Book to start and then modify based on how your motor performs.

 

Mark92131

 

[fastricky]

1 hour ago, Mark92131 said:

 

You could try some of Tii advance curves from the Blue Book to start and then modify based on how your motor performs.

 

Mark92131

 

 

Thanks! However my car is running great at rpm's under 4k, I'm keen to know what to set it at above that to the redline... 

[rstclark]

Your mechanical curve should be all in at max 36 degrees at 4000 rpm and stay a flat line from there to your redline 

[fastricky]

34 minutes ago, rstclark said:

Your mechanical curve should be all in at max 36 degrees at 4000 rpm and stay a flat line from there to your redline 

 

Got it thanks! 

[fastricky]

One question, according to the Blue Book, it should be at 25 degrees at 2700rpm. I've got it set at 29-30 now at high revs and it's an improvement over where it's been before, is there any worry about going as far as 36 degrees? I'd hate to see a piston shoot thru the hood! 😉 

[Cabbage Fumes]

The advantage of the Bluetooth version is you can play with the curve while it's running. A stock Tii likes the RPM and advance curve to be pretty closely matched. Start there. As a baseline for testing, try 3º at 500, 10º at 1000, 15º at 1500, 20º at 2000, 25º at 2500, 30º at 3000 RPM, then flat to 8000. If it runs fairly well at 30º in the upper RPMs, find an open bit of highway with the app open, and run it up to 4000 RPM. Get a passenger (please) to insert a new point at 4000 and go a few degrees higher in the curve screen, maybe 33º, and see if you feel an improvement or not. If yes, move the 3000 point up to this setting and flat line it to 8K. Whatever the case, what works best at 3000 is your "all in" number. If it's still early and you have time, do this at all the points in your curve. Running too much advance can be detrimental to your engine, and it will tell you when you've gone too far. More is not better, unless your car can handle it. If you have patience, you can butt dyno the curve pretty well. Every car is different, and the only way to answer what works best, is this. Remember that you need to log what works or not on paper, then create a new curve. You can't write anything to the 123 while it's running.

Edited August 17, 2023 by Furry Camel
I wasn't done talking yet.

[fastricky]

14 hours ago, Furry Camel said:

The advantage of the Bluetooth version is you can play with the curve while it's running. A stock Tii likes the RPM and advance curve to be pretty closely matched. Start there. As a baseline for testing, try 3º at 500, 10º at 1000, 15º at 1500, 20º at 2000, 25º at 2500, 30º at 3000 RPM, then flat to 8000. If it runs fairly well at 30º in the upper RPMs, find an open bit of highway with the app open, and run it up to 4000 RPM. Get a passenger (please) to insert a new point at 4000 and go a few degrees higher in the curve screen, maybe 33º, and see if you feel an improvement or not. If yes, move the 3000 point up to this setting and flat line it to 8K. Whatever the case, what works best at 3000 is your "all in" number. If it's still early and you have time, do this at all the points in your curve. Running too much advance can be detrimental to your engine, and it will tell you when you've gone too far. More is not better, unless your car can handle it. If you have patience, you can butt dyno the curve pretty well. Every car is different, and the only way to answer what works best, is this. Remember that you need to log what works or not on paper, then create a new curve. You can't write anything to the 123 while it's running.

 

Thanks for the response! Yes I will do this, but is there any worry about going as high as 36 degrees even if the car feels great like that? 

 

[TobyB]

I wouldn't think you could get into trouble at 36- I run an 11.x:1 race engine at that... (on 100 octane, but still)

 

t