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?
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?
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.
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.
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.
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.
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.
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.
123 ignition manual specifies not to use a coil with lower than 1.0 ohm. Is that the reason why we should add 0.6 ohm ballast to 0.6 ohm Blaster2 coil?
Yes.
The 123 limits current to 6 amps as well as specifying at least 1 ohm resistance. At low to medium rpm it is resistance that limits current but at higher rpm inductance is the limiting factor. Without the 123 current limit function a 1 ohm coil would draw 12 amps at low rpm but would drop below 6 amps at a higher rpm. The reason that a 0.6 ohm coil will give superior current and therefore spark energy is because inductance and resistance pretty much go together in ignition coils.
It is interesting that the GM HEI module used in Marelliplex can handle a lower resistance than 1 ohm but it limits the current to 5 amps.
From Pertronix, the epoxy filled Flame Thrower models are 40611 for 3 Ohm and 40111 for 1.5 Ohm. They recommend the 3 Ohm and it'll work fine on a stock 4 cylinder, but either will function with the 123. If you search by model number you'll find plenty of places to buy them.
Make sure you get an epoxy-filled model as the oil-filled ones are not recommended for sideways mounting like you have.
My posts 14, 16 & 31 gave details in different forms. I believe that the resistor comes with the coil when you buy a new Blaster 2 from MSD. Google it, search for it on ebay.
To clarify, if you buy the 1.5 Ohm Flame Thrower 40111 that you pictured you do NOT need a ballast resistor. You'd be fine with the 3 Ohm, honestly: with a stock, non-racing engine the 1.5 is just going to pull more current and run hot. But knock yourself out.
For the record, most modern coils have an internal ballast. The reason they used to use an external ballast is so that the ballast could be bypassed during cranking to get a hotter spark, then put it in series so you wouldn't melt the points during running. With modern electronic ignition there's no longer a need to use an external ballast.
The 123 is designed to operate with no ballast and with a coil of 1 Ohm primary or greater.
Really? Can you give a reliable source for that?
The fact that for most coils the inductance is approximately proportional to the resistance indicates that they do not have internal ballasts. The Bosch Blue coil which is a relic from slow revving air cooled VW's is the only one that I know of but of course it may have been copied by some of the aftermarket folks. Alfa's never used 3 ohm coils, at least from 1966 on and they were less than 1 ohm from around 1982. Why settle for a weaker spark than Alfa provided when you can have a much stronger one.
the 1.5 is just going to pull more current and run hot.
Completely wrong. The 123 controls the current both by limiting the maximum value and by varying the dwell angle as rpm changes. A 1.5 ohm coil comes closer to letting the 123 make the best sparks compared with a 3 ohm coil. It is at low rpm that coils tend to overheat and the 123 prevents that by shortening the dwell angle.
The reason I asked about the coil is that I can not open BP7ES or 6 plugs more than .030".
I can feel car doesn't like even .002 more (.032") on spark plug gaps. Can't remember if I tried resetting idle screws after the plug gap change though. Is it necessary?
I'm using 123 with "tuning" JK's curve, silver Bosch coil from CA on a hot 1750 street engine with RJR590/195 cams (11/10.4mm lift).
Tremec613, hope I'm not highjacking your thread...
Brand MSD
Emission Code 1
Inductance 8 mH
Maximum Voltage 45,000 Volts
Peak Current 140 mA
Primary Resistance .7 OHMs
Product Type Coil
Secondary Resistance 4.5K OHMs
Spark duration 350 uS
Turns Ratio 100:1
Weight N/A
Part Number 8203
If you are using the 123 ignition, I believe it calls for a minimum of 1.0 ohms. Others please let me know if I’m mistaken. So this wouldn’t be the correct product.
BrandMSD
Emission Code 1
Inductance 8 mH
Maximum Voltage45,000 Volts
Peak Current 140 mA
Primary Resistance.7 OHMs
Product Type Coil
Secondary Resistance4.5K OHMs
Spark duration 350 uS
Turns Ratio 100:1
WeightN/A
Part Number 8203
Brand MSD
Emission Code 1
Inductance 8 mH
Maximum Voltage 45,000 Volts
Peak Current 140 mA
Primary Resistance .7 OHMs
Product Type Coil
Secondary Resistance 4.5K OHMs
Spark duration 350 uS
Turns Ratio 100:1
Weight N/A
Part Number 8203
That will work fine with a ballast resistor of 0.6 ohms or similar. Note that the claimed inductance is 8 mH which is good. I have found that the inductance is a bit lower than they claim which is even better.
One thing that everyone should remember is that spark energy is directly related to coil current, the magnitude, the duration and the shape of the current pulse. Simply looking at coil resistance does not show coil performance. Clean running engines with very well controlled AFR that don't rev too high do not need high spark energy but engines with Webers that may not be perfectly tuned or which foul plugs can use all the spark energy that you can give them. If your Weber equipped car never has a lean hesitation or slight misfire under any condition then it may not benefit from a stronger spark.
Clean running engines with very well controlled AFR that don't rev too high do not need high spark energy but engines with Webers that may not be perfectly tuned or which foul plugs can use all the spark energy that you can give them. If your Weber equipped car never has a lean hesitation or slight misfire under any condition then it may not benefit from a stronger spark.
I'm setting up "new" DCOE32s on my car and still got slightly rough, hunting idle and a bit of hesitation on tip-in. Waiting on jets from Pierce manifolds and then I'll post a new thread. Meanwhile will be doing my homework, trying to wrap my head around all the info.
Thanks, I think I'll give this a try. My Verde seems to like your choice of MSD 8202 Blaster 2 Coil and NGK Iridium IXs
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