Greetings! I am getting fed up with points. I am looking into converting to Pertronix and I need some help figuring things out. Reading the PDF instructions on the Web, I see that you can run sans BR, but it also gives info about running with it. It also mentioned having some resistance, I think it is in the order of 1.5 ohms or so. My questions are:

Can I remove my ballast resistor? I rewired my truck so it now has one, rather than the resistance wire that came stock.

If I can remove my ballast resistor, do I need a different coil?

Currently, the ballast resistor supplies 6 volts to the coil when running, as it should. I believe the Pertronix is a 12 volt system. Does this mean to remove it and go with straight 12v when running?

Other notes:

Stock style coil from Oreilly auto parts
Used an EZ wire harness to rewire the truck



Thanks for the advice!

 

Remember, good quality points and condenser, installed in a serviceable distributor, work fine up to 5000+ RPM or so, absolutely no problems. They will need adjustment about every 8,000 to 10,000 miles.

Now with that out of the way, if you want to install an Ignitor module, you still need to couple that with a good distributor. The advance slots and weights get trashed, the vacuum advance, excessive wobble etc. This is probably why points get such a bad reputation today.

Everything needs to be mechanically sound. Point gap setting is really just a ballpark to get it to start and run. It's the dwell that counts. A worn distributor shaft makes a steady dwell impossible.

So a stock but fresh curved distributor, a Flamethrower coil, and an ignitor with 12+ volts works fine. You can open up the gap slightly on the plugs. Be sure to have good wires with good insulation, and solid grounds in the distributor. If the coil is installed sideways make sure the terminals are horizontal, not vertical. Supposedly coils should be installed vertically but I have not noticed a problem.

The key is to determine the current flow. About 8 amps or so is the limit. 14.5 volts / 1.5 = 9.6 ; but consider a coil is not always "ON", and there is always some additional resistance in the primary circuit itself.

Have been running Pertronics and Flamethrower coil along with a stock generator charging system for about 20 years no problem, ballast bypassed.

 

He is not using a Pertronix coil. He has a stock type coil which should have a resistor wire or ballast resistor.

 

Right, what I'm saying is, the best combination seems to be their Flamethrower coil and the Ignitor together, with the ballast bypassed. Run a full 12 volts constant.

The only thing is to make sure the distributor cap and rotor and wires and such are in good shape, or the fire will try to find another way to ground than through the plugs

 

I run 12V on my pertronix stuff with over the counter coils. Coil impedance is important though. In the Pertronix instructions it will tell you that you need a coil of so many ohms resistance. I'm pretty sure it follows how many sparks you have to make, IE: an 8 cyl makes twice the amount of sparks that a 4 cyl makes. I've walked into my local parts store carrying a multimeter and bought a generic coil of the specified ohms resistance. No problems.

I'm pretty sure that the resister found on points style ignitions is for points longevity. If I remember correctly, when the key is in the start position, it sends full voltage to the coil. In the run position, voltage is routed through the resistor. Smoking hot spark for starting, a little less once started. I've ran full voltage to points many times. Works well, but points don't last for doo doo.

 

What it is/was, points were a 6 volt deal. When they switched over to 12 volt systems in the 1950s, they left the point/coil/condenser system the same and used a ballast resistor to drop the voltage.

What they are really doing is dropping the current through the points. The voltage doesn't matter. Ya hafta go to Pertronix troubleshooting page where they talk about total amperage through the circuit and what will work. 8 amps is max.

A 3 ohm Flamethrower coil is used in the 4 and 6 cylinder engines, 1.5 ohm is spec'd in the 8 cylinder engines. They will get toasty in operation. This is normal. Don't turn the ignition to RUN for any length of time without the engine actually running. If the points just happen to be closed at this moment, it will send battery voltage through the coil primary windings with no place to go - and get way hotter than normal in a short period of time, spill oil all over, may explode etc. That's why ACC position was invented. Early Pertronix Ignitors would get smoked this same way too.

 

I have a pertronics i installed in my 74. the engine is a 351m out of something else.
i dont know all the tech stuff as the other posts. But i used the stock coil with built in resister from nappa and everything works great.

 

Pertronix instructions for the original Pertronix tells you to retain the ballast resistor for original coils and T into the wire before the resistor to run 12V to the Pertronix unit in the dizzy. I ran it this way for years before upgrading to a Pertronix II and coil, now use a straight 12V to both.

 

don't mean to Hijack this thread. But what about the MSD blaster 2 coil with the stock Duraspark 2 on a 77? Is the built in ballast resistor good enough?

 

What do the instructions say?

It's probably fine. Always double check. Although, some people claim MSD stands for "My Spark Disappeared." The overseas stuff is sometimes a little sketchy on QC.

 

Thank you guys all for your suggestions. I really would not mind keeping the points, but my truck does not seem to run well with them no matter what I do. Setting the dwell anywhere near where it should be results in loading up and backfiring under light throttle and low rpm. If I nail it at speed, it feels okay, but after a couple seconds, it will backfire through the carb. The truck really lacks power too. If I open the point gap, I get a bit more power, but it will hammer against the starter a little when cranking and part throttle performance is only decent. Pinging at a high rpm load is hard to avoid too. I have tried everything I can think of to stop this, but I just can't get the truck to run well. It also smokes points in a few hundred miles. I feel like the Pertronix may get me away from all this, but then again, maybe not.

 

Sounds like a bum distributor. Points were replaced for some very good reasons but, they work absolutely fine when setup right. An erratic dwell is evidence of this. It is true that an electronic module is less affected by this but other problems go along with excessive runout on the shaft.

If I had to choose only one, I'd pick a new or rebuilt distributor and use points, versus a Pertronix module and a clapped out dizzy.

Somebody finds an old truck in a field w/ 200k miles and the brakes are shot, springs and steering box worn out, clutch, distributor, generator, carburetor wacked out, but then think all of this was representative of how it was "back in the day".

It took me a while, finally got my dizzy "curved" today in fact. Ended up limiting the mechanical advance 24 degrees and 14 degrees initial for a total of 38 all in before 3000 RPM using one of Mr. Gasket's springs in place of that heavy secondary spring. This gives it a LOT more zip.

 

You would think, but the distributor is a reman unit, replaced about a month and a half ago. Everything seems really nice and tight, no wobble in the shaft. It makes me think to rule out a bad distributor, or a faulty reman unit.

Even when I get the truck running okay, it feels like there is a ton of power that is being wasted. My fuel economy reflects that, light acceleration and very moderate driving results in low single digit economy. It feels like I am pulling a heavy trailer everywhere I go.

 

Hm. Check to make sure damper marks are correct, that it hasn't slipped.

Then setup your distributor i.e. the advance curve.

Trust Me.

It can be tedious, but it's worth it.

"It doesn't matter what kind of ignition you have, if the advance curve is not set properly it won't make any power. The ignition is advanced so you reach peak cylinder pressure right after TDC (top dead center). If the spark comes too soon the burning fuel will try to push the piston back down the cylinder before it reaches TDC, resulting in a loss of power and possible engine damage. If the spark is too late you will not reach full power and get poor gas mileage."

http://www.gofastforless.com/ignition/advance.htm

 

I've stated that I run pertronix stuff, and I do, but on my truck, even though it's in my sig as stock, I run a GM style HEI ignition. I recently bought a kit to adjust my timing curve, but haven't gotten to it yet. If you don't mind looking at a GM distributor under your Ford hood, you should get one. They are cheap, dependable, long lasting, and somebody makes one for ALMOST every application. I run pertronix on a 6 cyl Continental and a two cyl Wisconsin.