Tach Sending Units W/ Pertronix Ignitor & Coil
70 yr old Newbie here with a 53 Commander on a 62 Hawk frame
& dash, & a 259 engine. Bought it that way. While under the
dash removing the clock and a couple of switches to rebuild, I evidently
knocked two partially bare wires from the tach sending unit together.
Needless to say, I now have a non working tach. Once the smoke cleared,
I crawled back under there & started looking at the wiring. On
Red: Brings the power from the Ig. switch
White: Goes to the Tach gauge
Black: To ground
Yellow: Returns from the tach gauge to the 8 plug
Green: Connects to the junction post & connects with the pink resistor wire going to the coil.
Since I felt I fried something in there, I started checking voltages. Had 11.6 at the junction post
which seamed reasonable. Checked the end of the resistance wire at the
coil and it had dropped to only 5.3 volts. I thought perhaps thats the
reason the car was a little hard starting. Went on the net & got
Pertronix instructions which say the resistor wire should be replace by a
reg wire & should have 12 volts at the coil. Did that & what a
difference. Car starts immediately & seems to run much better.
Getting close to my questions. There are two aftermarket senders out
there. Stude Int & Studebaker Parts .com. The old threads say both
had problems a few years back. Is anyone running one of these units
with the Pertronix Ignitor and coil successfully utilizing the full 12
volts & not the resistor wire to the coil? If so, how is it wired?
Both of the above are wired differently. Help me get that old tach
working again. Can both handle the 12 volts feeding back?
I did pick up one interesting bit of wiring info that would help ease
hard starting cars. Run a wire from your starter relay to the coil on
any unit that still has the resistance wire or a resistor in the wire to
the coil. This will give you a full 6 or 12 volts to the coil only
when the starter is engaged. Should give you a much better spark at the
Last edited by Steve L; 07-04-2011 at 03:57 PM.
Reason: word correction
This is not new news, all 1956 and later
Studebakers and all others with 12 Volt systems (including all Fords)
are already wired somewhat this way. The 12V Solenoids all have the "I"
(Ignition) small terminal as well as the small "S" (Start) terminal on
them accomplishing the same thing.
Originally Posted by Steve L
Well, lacking a response to my question, I called & talked to the people at Studebaker Int.
They were also unsure, so they called their supplier that makes the
unit. The answer came back as a yes it will work with the Pertronix
coil & ignitor. It was stated many customers use this combination.
The sender counts pulses and sends them to the tach. It doesn't care whose unit creates the pulses.
So, I ordered one. Will post the result when installed.
Better late than never. I ended up ordering the tach sender from
Stude Int because it was wired like the old one. (800009) Got one
like the one sold by Stude Parts.com, so there is only one replacement
type out there now that I could find for the 1962 rectangular Hawk type.
The nice part is it works, but you have to wire it differently. Wire
it the same & you will burn it up. **The blue wire goes to the
negative side of the coil.** Brown wire goes to the brass terminal on
the tach. Red wire goes to 12 volt ig. switch. the white wire goes to
ground. You will also need to run another ground off the tach steel
terminal to ground. This is in addition to the one already there for
the tach light. This unit had some jumps to it so it has a problem
handling a full 12 volts to the positive side of the coil. Felt all my
grounds were good. Called Pertronix technical dept to ask if I should
reducd the voltage going to the coil. They said they would rather add a
10k-Ohm 1/2 watt resistor to the blue feed wire going to the tach
sender. Did that & it did improve the stability. Still a slight
jump at idle, but seemed smooth above 800-1000rpms. It has a
potentiometer (sp) that allows for fine tuning, so seems to work pretty
Found info on Bob's site that was very informative.
https://]www.studebaker-info.org/tech/tach/tachpert.html[/URL] Shows the
insides of the old unit & even how to rebuilb it if you are so
inclined. I was thinking about that until I saw how small the wires
were. Even tells you how to test your tach with a 1 1/2 volt battery.
Hope this helps someone. Thanks 64VK7 for your info. Appreciate it.
Tags for this Thread