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Discussion Starter #1 (Edited)
Do I have it right?


My 1973 spider is a negative earth car, correct?




Therefore

Red wire from 123 ignition to positive on coil

Black wire from 123 ignition to negative on coil


Green wire from firewall to negative coil


Is that all?




Will a flame thrower coil work with a 123 ignition?

Does the coil itself need a ground wire going from the negative to the body?

Thank you all very much in advance!
I seriously appreciate all the help!
 

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Green wire from firewall to negative coil
No! Your drawing clearly shows power supply to coil to positive connector!
Green/black wire (from ignition switch) needs to be connected to +/15 @ your coil.

Does the coil itself need a ground wire going from the negative to the body?
No.
 

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Discussion Starter #3
No! Your drawing clearly shows power supply to coil to positive connector!

Green/black wire (from ignition switch) needs to be connected to +/15 @ your coil.







No.


Thank you! Previous owner had it wired incorrectly, I was wondering why he stated I would need to “figure out ignition”.

As for spark plug wires, am I right in assuming the longest wire goes closest to the firewall and the shortest closer to the radiator?
Very obvious I know! Just making sure..


In addition how do I determine which spark plug wire goes into which port on the distributor?

Thanks for the help!
 

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That looks like a Flame Thrower 2 coil. If that's the case then it's 0.6 Ohms and won't work properly: the 123 requires minimum 1 Ohm primary coil resistance. It's also sideways mounted, and that's not recommended for liquid-filled coils.

A proper coil in the Pertronix line would be the Flame Thrower 40611. It is 3 Ohms and epoxy-filled.
 

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In addition how do I determine which spark plug wire goes into which port on the distributor?
- take out plugs # 4 and # 1
- do turn your motor clockwise by pushing forward in 5th gear (WITHOUT having ignition ON !! It must be OFF !) until your arrow indicator on your front cover points to TDC on your pulley
- then take a flashlight and lighten into plug hole. You´ll either see on
cyl. #1 OR on cyl. # 4 both valves slightly off seat. That´s the cylinder which you WON´T connect to the plug lead in that moment your rotor is pointing to on your dizzy to a specific port at your cap. You do connect that lead to the other one (means # 1 OR 4 !). Then start fitting the other plug leads clockwise from that one you´ve already fitted after indicating either in order 3-4-2 (when you´ve indicated the first lead going to cyl. # 1 - which is next to water cooler) OR 2-1-3 (when #4 was at TDC before)

OR: Take off valve cover, turn engine to TDC # 1 (cam lobes pointing both to the outer sides !), and start then with cyl. #1 / dizzy rotor pointing in that moment to a specific port in your cap.
 

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- then take a torch and lighten into plug hole...
a few years back, I once advised someone to look inside the gas tank with a torch...........luckily they didn't!;)

In the USA a 'torch' is a butane torch or a blowtorch.
They use the word flashlight.
 

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Discussion Starter #9 (Edited)
- take out plugs # 4 and # 1
- do turn your motor clockwise by pushing forward in 5th gear (WITHOUT having ignition ON !! It must be OFF !) until your arrow indicator on your front cover points to TDC on your pulley
- then take a flashlight and lighten into plug hole. You´ll either see on
cyl. #1 OR on cyl. # 4 both valves slightly off seat. That´s the cylinder which you WON´T connect to the plug lead in that moment your rotor is pointing to on your dizzy to a specific port at your cap. You do connect that lead to the other one (means # 1 OR 4 !). Than start fitting the other plug leads clockwise from that one you´ve already fitted after indicating either in order 3-4-2 (when you´ve indicated the first lead going to cyl. # 1 - which is next to water cooler) OR 2-1-3 (when #4 was at TDC before)

OR: Take off valve cover, turn engine to TDC # 1 (cam lobes pointing both to the outer sides !), and start then with cyl. #1 / dizzy rotor pointing in that moment to a specific port in your cap.


Thank you for the write up!

Is this correct?





More reference material for when I tackle the ignition:

 

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Forget the last picture; should a PO have already changed the oil pump, then the pointing direction of rotor COULD be different; just follow the instruction to find No. 1 and then start fitting clockwise the other 3 leads.

Your 1-2-3-4 picture is correct. But firing order is 1-3-4-2.
 

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Discussion Starter #11
Forget the last picture; should a PO havd changed already your oil pump, then the direction of rotor COULD be different; just follow the instruction to find No. 1 and then start fitting clockwise the other 3 leads.



Your 1-2-3-4 picture is correct. But firing order is 1-3-4-2.


Thank you!!
 

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Discussion Starter #12
That looks like a Flame Thrower 2 coil. If that's the case then it's 0.6 Ohms and won't work properly: the 123 requires minimum 1 Ohm primary coil resistance. It's also sideways mounted, and that's not recommended for liquid-filled coils.

A proper coil in the Pertronix line would be the Flame Thrower 40611. It is 3 Ohms and epoxy-filled.


Thank you so much! You probably saved me hours of troubleshooting!
Will any of these work by chance?

 

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For best performance use a 0.6 ohm coil with a 0.6 ohm ballast resistor. I posted simulations for the relative performance of that setup compared with a 1.5ohm and a 3 ohm coil. The 0.6 makes much more spark energy above 3000 rpm due to the lower inductance of the 0.6 ohm coil. MSD supply a suitable ballast resistor with a new Blaster 2 coil.
 

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Discussion Starter #15
For best performance use a 0.6 ohm coil with a 0.6 ohm ballast resistor. I posted simulations for the relative performance of that setup compared with a 1.5ohm and a 3 ohm coil. The 0.6 makes much more spark energy above 3000 rpm due to the lower inductance of the 0.6 ohm coil. MSD supply a suitable ballast resistor with a new Blaster 2 coil.


Would the ballast resistor depicted on my second picture work with my current flamethrower?



+

 

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Performance curves

I posted this comparison in another thread.
 

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12V supply goes to the wire of the 123 that should be connected to 12 volts. It also goes to one side of the ballast resistor.
The other side of the ballast resistor goes to the +ve terminal of the coil.
The rest of the wiring is the same.
I have only used the original, 2 wire 123 distributors. In my case 12v goes to the red wire of the 123 and one side of the ballast resistor and the other side of the ballast resistor goes to Coil +ve. The black wire from the 123 goes to coil -ve.

The original data is around post 275 of this thread https://www.alfabb.com/bb/forums/engine-management/157401-123ignition-distributor-15000-miles-road-test-19.html#post7770050
 

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Tremere - I would need to know the specification of both the ballast resistor and the coil (ohms and inductance) to calculate the performance but provided they are in good condition they should exceed the performance of a 3 ohm coil.
 

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Discussion Starter #20 (Edited)
Tremere - I would need to know the specification of both the ballast resistor and the coil (ohms and inductance) to calculate the performance but provided they are in good condition they should exceed the performance of a 3 ohm coil.


Understood

How about a specific coil recommendation from classic Alfa? Please include product number if possible

classicalfa:



Or maybe from centerline?

 
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