123Ignition Revisited - Page 3 - Alfa Romeo Bulletin Board & Forums

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post #31 of 56 (permalink) Old 09-29-2009, 07:44 AM
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Quote:
Originally Posted by alfaparticle View Post
Static advance, as it's name implies, is with the engine stationary - zero rpm.

Try the following:
Set the pointer to "P" with the motor at TDC on #1 cylinder.
Measure the outer diameter of the engine pully.
Calculate the distance on the circumference of the pulley for 1 degree of crankshaft rotation
=D*pi/360
Calculate the distance for the static advance that you require.
Measure that distance from "P" and mark the pulley.
Follow the 123ignition instructions to make the green light just come on with the pointer at your new mark.

You can also calculate the distance for your 'M" position and mark the pulley. Use your strobe to verify the max adavance is at your new 'M" mark.
Appreciate your explanation....

I just checked the pulley....It was a modified version for air conditioning belt.

there is a mark... but not sure if it is F or P?

At 1000 rpm idle, the timing strobe show the pointer pointing at the mark.
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post #32 of 56 (permalink) Old 09-29-2009, 10:02 AM
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another method

alfaparticles method is probably the best way to go.

The lazy man's technique is to use a timing light that allows "dial back". With this method, you dial back the advance until the P mark lines up with the arrow again. this will then show you how much advance you have by reading it off the dial on the timing light.
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post #33 of 56 (permalink) Old 09-29-2009, 05:07 PM
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Here are my numbers. I used them this weekend to set up the Shankle curve:
Pulley Diameter = 4.94"
1 degree = .043" = 1.095 mm

F is 4 degrees = 0.,172" = 4.38 mm
M is 36 degrees = 1.552 ' = 39.42"

Now it's up to you. If you want to know that advance for a curve at 1000 rpm, then figure it out from the curves and mark your pulley for that advance.

Or you could shell out $60 for a strobe with variable advance and just use the P mark.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #34 of 56 (permalink) Old 09-29-2009, 10:29 PM
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I saw this on the IAP's website....

Alfa 4-cylinder Timing Marks



What are those strange letters on the Alfa Romeo crankshaft pulley?
They stand for Italian words:

F – ("Fissa")=Fixed. The correct advance for static ignition timing.

P – ("Punto")=Top dead center.

M – ("Massimo") = Ignition timing at maximum advance (usually 5000 rpm; see above).

I – ("Iniezione") = Crankshaft position where SPICA injection pump's timing marks are aligned (where fitted).


Does that mean that F has less advance degree than P?
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post #35 of 56 (permalink) Old 09-30-2009, 04:14 AM
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Yes, but this pulley is for an emasculated, SPICA injection, US spec car that had barely enough power to pull the skin of a rice pudding. This one had static timing of several degrees after TDC. Most pulleys will have the F mark between the P and the M.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #36 of 56 (permalink) Old 09-30-2009, 04:18 AM
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Quote:
Originally Posted by alfaparticle View Post
Yes, but this pulley is for an emasculated, SPICA injection, US spec car that had barely enough power to pull the skin of a rice pudding. This one had static timing of several degrees after TDC. Most pulleys will have the F mark between the P and the M.
I see.... this is the part that confuses me. Thanks for the clarification!
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post #37 of 56 (permalink) Old 10-08-2009, 01:50 AM
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Quote:
Originally Posted by alfaparticle View Post
Here are my numbers. I used them this weekend to set up the Shankle curve:
Pulley Diameter = 4.94"
1 degree = .043" = 1.095 mm

F is 4 degrees = 0.,172" = 4.38 mm
M is 36 degrees = 1.552 ' = 39.42"

Now it's up to you. If you want to know that advance for a curve at 1000 rpm, then figure it out from the curves and mark your pulley for that advance.

Or you could shell out $60 for a strobe with variable advance and just use the P mark.
I did a measurement and found that my pulley is the same size as your measurement.... and at the specified 36 degree, I found a notch.

So I proceed the set the distributor for maximum advance....

With that setting, I don't notice any pinging when the engine was warm. But when the engine is cold, for about 5 minutes of initial driving, I notice minor pinging at about 3K rpm and above. No more pinging once the engine warms up to water temperature of 50 degrees C.

Should I back it out a bit?
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post #38 of 56 (permalink) Old 10-08-2009, 03:56 AM
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Pinging normally only occurs at large throttle openings and it is advisable to go easy on the gas until the engine is fully warmed up. So for me it would not be a concern. I have run curve #1 with 40 degrees full advance with no pinging on 91 octane gas.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #39 of 56 (permalink) Old 06-20-2016, 02:17 PM
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hello to all, i have a 2000 gtv with 123 ignition, e read alot in this forum and for all the internet, some grafics that i saw i really do not believe that are good so i call for Albetronic the manufacture of 123 igiton and there are some differences from waht they tell me for the curves that i saw, so for all that want to try they tell me:

Curve D: or JK curve

Deg./ Rpm
0 @ 1000
21 @ 4000

Curve E or Shankle 4255

Deg. / Rpm
0 @ 700
20 @ 1300
32 @ 4000
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post #40 of 56 (permalink) Old 06-20-2016, 06:03 PM
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Quote:
Curve D: or JK curve

Deg./ Rpm
0 @ 1000
21 @ 4000

Curve E or Shankle 4255

Deg. / Rpm
0 @ 700
20 @ 1300
32 @ 4000
This data matches the curves in post #19.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #41 of 56 (permalink) Old 06-21-2016, 03:38 PM
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Alfaparticle, if you spend some time comparing the data you will see that is not the same as show on post #19, and that is the reason that i post it.
With best regards.
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post #42 of 56 (permalink) Old 06-21-2016, 04:51 PM
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Quote:
Alfaparticle, if you spend some time comparing the data you will see that is not the same as show on post #19, and that is the reason that i post it.
With best regards.
I created the graphs in Post 19. I have raw data for all of the 123 curves. Do you understand that you must add the static timing to the raw numbers to get the real curve or do you think that you should always have 0 degrees static timing?

The full data (not just 3 points) is in post # 10. Post #9 refers to normalizing the data so that the curves can be compared. The result of that normalization is in post # 19.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke

Last edited by alfaparticle; 06-21-2016 at 05:51 PM.
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post #43 of 56 (permalink) Old 06-22-2016, 05:37 AM
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Alfaparticle thank you for your explanation, can you post a photo of how i must Set the advance on the vaccuum, thanks in advance and sorry for the double post, i dont want the credit on your work but i thougth that i post new curves.
Thank you
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post #44 of 56 (permalink) Old 06-22-2016, 05:57 AM
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I have not used a 123 vacuum distributor. For a non vacuum type: choose your advance curve, choose your static timing, make a static timing mark on the pulley, set engine to static timing mark, rotate distributor counter clock wise until green LED just turns on.

Calculating the timing mark is described in an earlier post in this thread.

This probably works for vacuum advance distributors too.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #45 of 56 (permalink) Old 06-22-2016, 06:48 AM
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Quote:
Originally Posted by alfaparticle View Post

This probably works for vacuum advance distributors too.
the only thing is little diferent is you need to pull the vacuum line from the distributor and then check your static timing.
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