1928 buick standard six, ignition?

[Rod L]

I'm a little bored so I checked the plugs and found all 6 to be set at .020 I reset them to .025 resulting in some improvement. Then I got to thinking about the coil. I have a "Pertronics" # 40011 1.5 ohm brand new in the box. can I use it , or am I better off using a 3.0 ohm?

 

Rod

[TerryB]

Petronix seems to indicate the 1.5 ohm coil is best with 6v systems while the 3 ohm is best with 12v systems.  With a 1.5 ohm coil the current draw of the coil is 4 amps (6v/1.5ohm).  With 12v the 3ohm coil will also draw 4 amps.  Be sure your plug wires, cap and rotor are in good shape to handle the higher voltage the coil is going to make, they claim up to 40,000 volts on the secondary side, that’s a lot of bang for an early system.

[Rod L]

 

Thanks Terry,

I'm just playing around trying to see what works and what doesn't. The wires and rotor appear to be fairly new. That pertronics site is a little confusing with their charts etc, which is why I asked the question. I'm going to play with this a bit, changing plug gap trying to find a sweet spot. I bought an "innovate LM-2"  exhaust gas analyzer  recently in an effort to dial this thing in, but with only an end of tailpipe sniffer it isn't steady enough to do much good, might have to weld in a bung further up the pipe for the O2 sensor?   

Rod                                                                                                   

[TerryB]

It can be confusing!  If you put the 3 ohm coil in a six volt system you would get only 2 amps though the coil which would decrease the output voltage accordingly.  It’s the primary side current and turns ratio between the primary and secondary that determines the secondary high voltage produced.  
 

I’ve never played with oxygen sensors so your gear that measures that should help to some degree to better tune the running of the car.  The early cars seem to run rich due to somewhat simple carburetor design.  It’s often air leaks in the carb butterfly shaft that makes them more lean or having the wrong carb on the car.  
Good luck,

Terry

[41 Su8]

Double check your voltage at the coil to be sure it is 6 volts. Pertronix needs a minimum of 4.5 volts to operate. If you don't have at least 4.5 volts you may need to run a dedicated wire from the battery through a switch and then to the coil.

[Rod L]

3 hours ago, 41 Su8 said:

Double check your voltage at the coil to be sure it is 6 volts. Pertronix needs a minimum of 4.5 volts to operate. If you don't have at least 4.5 volts you may need to run a dedicated wire from the battery through a switch and then to the coil.

41,

Perhaps I am misunderstanding your statement, but I am not running a Pertronix module, just their coil.

Rod

[41 Su8]

You are right,  I thought you were running a module. Sorry about that.