pertronix ignition upgrade - where to tap for 12V?

[SANdMAN_the]

i'm in the middle of completing the pertronix ignition upgrade and surprise surprise - my car doesn't start anymore. i don't have any spare wire tonight to verify that i have the low voltage problem, but assuming that i do, where can i tap for 12V controlled by the ignition?

thanks,
john

 

[dklawson]

I think that depends on what vintage your car is. There are a couple of places to start looking even if you don't have a wiring diagram. If your ignition is ballasted (as it sounds like you suspect it is) look for a "white" wire leaving the ignition switch (don't use other colors leaving the switch). If you don't find that, look for solid green wires. Use a volt meter to confirm that your choice is both +12v AND switched on and off by the ignition key.

 

[Tullamore]

Re: pertronix ignition upgrade - where to tap for

On my Sprite it had many open connectors in the fuse block. These are ignition switch controlled and where I got my power for the radio and electric fan relay.

 

[sparkydave]

Re: pertronix ignition upgrade - where to tap for

Hi John, it would help to know what year your car is. I put one of those on mine since the factory electronic ignition died, but I made use of the 12 volt lead that went to the old ignition module. The fuse block would probably be the next place, unless you have a discrete ballast resistor instead of a resistor wire. Mine had the latter.

 

[SANdMAN_the]

Re: pertronix ignition upgrade - where to tap for

thanks for the suggestions! my baby is a 1969 midget. i'll try using the old 12V lead since that sounds like it requires the least amount of surgery.

john

 

[dklawson]

Re: pertronix ignition upgrade - where to tap for

I don't think a '69 would have had ballasted ignition. If that's true you can make the Pertronix red wire connection to coil (+) (assuming negative ground). A quick way to tell is to hook your volt meter between coil (+) and chassis ground. Hook up a temporary jumper wire between coil (-) and ground. Switch on the ignition and read the volt meter. If you get less than 12v (like 9v or 6v), find another supply for the Pertronix.

Don't omit the jumper wire to ground when doing this test. You must have current flowing through the coil (and any ballast resistor) to accurately measure the voltage at the coil (+) terminal. If the jumper isn't there you may not have current flowing through the coil unless you know for a fact that your points are closed.

 

[SANdMAN_the]

Re: pertronix ignition upgrade - where to tap for

you're right doug, there isn't a ballast resistor on my coil and i currently have the pertronix leads hooked up directly to the coil. thanks for the tips with the jumper wire!

john

 

[SANdMAN_the]

Re: pertronix ignition upgrade - where to tap for

ok, so i've hooked the pertronix directly to a 12V supply (the fusebox) and verified it's seeing 12V, but the car still doesn't start. i did notice that i am not plugging the low tension lead that originally went to the distributor anywhere. is this loose end causing my problem?

thanks again,
john

 

[dklawson]

Re: pertronix ignition upgrade - where to tap for

There shouldn't be any problem with the old black/white wire being loose. Just to double check...
Pertronix Red to switched +12v
Pertronix Black to coil (-) (negative ground?)
Distributor WELL GROUNDED. The 23/25D dizzys should be OK but you may want to add temporarily a braided wire between the breaker plate and the dizzy shell just to be sure.

Back to basics. The nice thing about the original Pertronix is that you can set the car's static timing (Pertronix II won't let you do this). HOWEVER, it is important that you limit the time the ignition is on without the engine running to no more than two or three minutes. The module will overheat if you leave it on without the engine running.

I assume you know how to set static timing using a test lamp. (If not, post back and we'll put up a short version of the procedure). Hook up your test lamp and set the static timing like you would for a points setup. If the Pertronix is working correctly you'll see your test lamp turn on and off at the appropriate times indicating that it's working and that your car is ready to start. This test will let you know that the timing is right and that the Pertronix is working.

 

[SANdMAN_the]

Re: pertronix ignition upgrade - where to tap for

my setup is how you describe (my car has a negative earth):
pertronix red - fusebox (+12V)
pertronix black - neg on the coil

i don't know if my dizzy is well grounded, i was having trouble with the battery charging earlier this year and had to run a ground from the battery to the block. i'll run an additional ground wire from the dizzy to my grounding point.

i have been careful with how long i've left the ignition on while i've been checking voltages and such.

i've never set the timing on the car myself yet. i'll read up on how to do it in the haynes, but i would appreciate it if you could post up a quickie write up on how to do it.

thank you again,
john

 

[dklawson]

Re: pertronix ignition upgrade - where to tap for

John, this is my "short" explanation of static timing. I'm assuming you have certain tools and/or know certain things. If anything below is unclear, please ask me about it. My biggest thing is, I only turn the components in directions to take out the backlash in the timing gear. I'm very careful about this. Others will tell you it's not that important. In my notes below I talk about "points". Substitue "Pertronix" in those places and procede as normal. Just remember to switch off the ignition as soon as you've set the static timing... or pull the Pertronix red wire off wherever it's connected to so it's not energized for too long.

***************************
Static Timing

In static timing the engine is set to a pre-determined number of degrees of rotation before top dead center and the distributor is rotated to open the points. The position at which the ignition points open is the point at which the coil fires. To perform static timing you will need the necessary wrenches to loosen your distributor’s mount and you will need a test lamp or volt meter.
Begin by marking and removing the spark plugs (this will make the engine easier to turn over). Put the car in neutral and use the fan belt or other means to turn the engine over until the desired timing marks line up. (Alternatively, leave the car in 4th gear and push/pull the car to turn the engine over). You’ll need to know what the static timing for your engine needs to be, consult your Haynes or other manual. If you have no idea and you have no manual, you can try about 5 degrees before TDC. Turn the engine over ONLY in the normal direction of rotation. If you back up… back up at least 1/4 revolution, then go forward again. This is to eliminate backlash in the timing gear from affecting your settings.
Connect the first lead of the test lamp (or volt meter) to the coil terminal that is connected to the distributor. On LBCs this is typically the terminal with the white/black wire. Connect the other lead of the test lamp to chassis ground. You will need to know the NORMAL direction of rotor rotation for your distributor. (Lucas 23/25/45 series distributors have counter clockwise rotation of the distributor rotor).
Loosen the bolts that secure the distributor to the block and switch on the ignition. With the timing marks lined up as mentioned above, turn the distributor body in the direction of ROTOR rotation until the test lamp is OFF and then a few more degrees.
With the lamp off, SLOWLY rotate the distributor body in the OPPOSITE direction of rotor rotation (clockwise for Lucas 23/25/45 distributors) until the test lamp JUST lights up.
Switch off the ignition, tighten the distributor clamp bolts, remove the test lamp and replace the spark plugs. You’re done.
Be careful to check that you’re setting the timing with #1 cylinder and not #4 (in the case of 4 cylinder engines). If you’ve removed the dizzy you probably need to verify this by removing the valve cover and looking at the valves for #1 and #4 cylinders. You should be setting the static timing when both valves on #1 are “up”/closed and valves on #4 are “down”/open. If you look at the dizzy cap at this point and put the rotor on the dizzy cam, the rotor should be pointing at/near the lug to which the #1 spark plug wire is attached.

 

[SANdMAN_the]

Re: pertronix ignition upgrade - where to tap for

thank you very much for the writeup! unfortuantely, i didn't get around to setting the timing this weekend...but a 3day weekend is just around the corner ;-)

john

 

[Dave Russell]

Re: pertronix ignition upgrade - where to tap for

[ QUOTE ]
Substitue "Pertronix" in those places and procede as normal. Just remember to switch off the ignition as soon as you've set the static timing... or pull the Pertronix red wire off wherever it's connected to so it's not energized for too long.

Turn the engine over ONLY in the normal direction of rotation. If you back up… back up at least 1/4 revolution, then go forward again. This is to eliminate backlash in the timing gear from affecting your settings.

With the lamp off, SLOWLY rotate the distributor body in the OPPOSITE direction of rotor rotation (clockwise for Lucas 23/25/45 distributors) until the test lamp JUST lights up.


[/ QUOTE ]
Hi doug,
A very good, comprehensive description. To add just a bit of "illumination", Not only should the rotor be backed off & then turned forward, to eliminate gear backlash, but the Pertronix requires backing off to reset the electronics before it is able to switch again as it reaches the firing point. This means that "slowly backing up the distributor until the lamp just lights" may not work since the electronics may not be reset. Maybe multiple forward passes would be better.
D

 

[dklawson]

Re: pertronix ignition upgrade - where to tap for

Good points Dave. I hadn't really given it much thought, but I did have to go CCW with the dizzy body more with the Pertronix to get the light to go "off" before turning it back forward to get the test lamp "on".

 

[SANdMAN_the]

Re: pertronix ignition upgrade - where to tap for

it looks like i must have accidently burned the pertronix module :-( after several attemts on checking and rechecking everything, i got fed up and put back points, set them to .015 and she fired up like a champ.

i was a little surprised how easy setting the points was though...i was expecting something more difficult.

thanks for all your help!
john