View Full Version : Petronics ignition install questions

05-01-2017, 11:50 AM
I am installing a petronics ignition On my 63 TBird. It is of course a 390 with stock original Distributor. Seems pretty straight forward but after reading some stuff on line I thought I would ask you guys for any advice you could give me.
1) Do I need to open the spark plug gap?
2) Will advancing the timing be beneficial at all.
3) Is there something else I should know about from anyone own experience.
I did get a new cap and rotor and the Petronics fluid filled coil.
Thanks guys for any help you can give me.

05-01-2017, 12:36 PM
Make sure you get a full 12 volts to the distributor at run.

The gap is a function of the coil. You can probably open up from 0.034 to 0.038 or so.

Timing advance is more a function of the fuel you are using and your carburetion. Modern fuels burn slower so what I've been told is a higher initial, delayed advance, and a total advance of about 34 degrees.

My setup is a Pertronix distributor, Ignitor II kit and matching coil. I'm using 93 E10 pump gas with throttle body EFI. Initial advance is 16 degrees BTDC, centrifugal starts at 1500 rpm and all in adding 18 at 3500. My vacuum advance is metered above the throttle plates so adds in a little more at higher RPM. I also went with one heat range colder plug with a gap of 0.035.

05-01-2017, 12:54 PM
Thanks for the info. I use the same gas, i will have to see what the fuel will take as I advance. The car has been stored for quite a while prior to me getting it. I am getting spark knock now at higher RPM. Just getting to the motor now, I redid the suspension and trans. Thanks for the input it will be a help.

05-01-2017, 03:37 PM
Here's my Original Equipment (OE) distributor curve vs. my new one. The Motorcraft is more tedious to adjust and not as adjustable. There are threads here with links to how to do it. On the downside of the new distributor, it's taller so I had to bang on my air cleaner a bit.

The OE has one spring that is "loose" in the fitting. The first spring starts to advance right at off-idle, rises quickly, then the second spring kicks in and it slows down on the rate, then hitting the 24 degree limit at 2800 rpm. (Again, the limit can be reduced).

The Pertronix advance depends on the springs used in the kit, S or B. Both springs are tight off the mark, so the curve is more linear. I chooses a mix of the two and limit to 18.

05-01-2017, 08:15 PM
...I am getting spark knock now at higher RPM...Distributor curves on every engine depend on the LOAD. So, 'advance machines' are simply ballpark settings. Since the same engine can be used in a heavy or very light car/truck applications, the advance curve will be very different depending on the load. An EFI setup will be different as well because fuel delivery is atomized under high pressure.

Distributor machines can simulate engine speed but they cannot simulate your engine under a load. If you are getting knock, your distributor is too far advanced. Here's my setup procedure: Click Here (http://www.squarebirds.org/simplyconnected/390Build/Distributor.htm) - Dave