Electronic Ignition Question

[RainMoore]

Hi all,

    I'm interested in upgrading from a points system soon but I'm unsure on what would be best to replace.

 

I'm looking at the Pertronix Ignitor II for the auto dwell, and Figure while I'm at it I may as well add a flamethrower coil to the mix.

 

I've got a '74 automatic with a Bosch Blue coil, and no resister wire. I'll have to check the resistance of the coil itself again, but I believe I was getting somewhere around 1-1.5 ohms across the + and - on the coil.

So would I need the 1.5 or 3 Ohm Flamethrower? I'm confused by articles I've read online. Or would it be a better bet to stick with the Blue Coil I have, or look into the Bosch black or red? A lot of people on here are super loyal to the latter two.

 

Also, when installing the pertronix, where does the tach wire end up? Can it simply attach to the (-) terminal on the coil?

 

Thanks!

[esty]

i'd use the blue coil you have...the tach wire connect the same pace (-) terminal on coil

 

hot spark is a lot less money than Pertronix....i Hot Spark it on all my cars and have never had to replace one....yet

 

[Mike Self]

Once again donning my contrarian and vintage electronics hat...

 

I've used Delta Mark 10 CD (Capacitive Discharge) ignition boxes for nearly 50 years; don't think they're still being made but show up on E-bay fairly often, and were also sold as kits by Radio Shack, and under different names (I have a NOS "Tiger 500" box that's identical to the Delta and made by the same company).  I even have a 6 volt one on my Renault.

 

The plus factor is that you continue to use your points, but they only serve as a trigger relay, so carry only +12 volts rather than plug voltage so don't burn out.  And if the box goes bad, press a switch on it and you're back to conventional ignition with no other actions. My '69 has had a Delta unit on board since June 1969, and is on its third set of points after 226k miles (no that's not the car that had the condenser problem a few posts ago).

 

If you can find a Delta (or one of its clones) unit, give it a try.  Easy install and very reliable.

 

mike

[esty]

delta mark 10 - ebay

 

Mark-Ten-Capacitive-Discharge-Ignition

 

[Preyupy]

I have found over the last 10-15 years that the quality of ignition points           ( Bosch, Lucas, GM, Ford and especially the aftermarket brands) have taken a turn towards the worst. It was not uncommon for 4 cylinder points to stay stable well past 7000rpm so the only reason to change to some other kind of ignition triggering device (even WITH points ignition is still electronic) 

 

I frequently have to try 4-5 sets of points now to find one that does not start to “float” and scatter the spark at 5000rpm and even lower. 6 cylinder BMW’s used the same points as the 4 cylinders and start to float even sooner.  Using something like the Delta Mk10 does not change this, it does lower the amperage through the points and as such they do not “burn” as quickly but it makes no difference when they start to float. 
 

We run Pertronix igniters in over 80% of our race cars ( not just BMW’s) and have never had a failure. They are also dead stable to well over 11,000rpm on the Cosworth BD and M12 BMW engines. I have also adapted them to work in  vintage 12 cylinder engines amongst others. 

[Son of Marty]

Plenty of people running pertronix and the blue coil, on general principle changing one component at a time will make trouble shooting any bugs easier by a factor of about 10.

[jimk]

2 hours ago, RainMoore said:

So would I need the 1.5 or 3 Ohm Flamethrower? I'm confused by articles I've read online.

Download and read what Pertronix requires for coil primary winding resistance.  Too low a resistance and the high current thru the Pertronix burns out the Pertronix.

[Lorin]

1 hour ago, Preyupy said:

I have found over the last 10-15 years that the quality of ignition points           ( Bosch, Lucas, GM, Ford and especially the aftermarket brands) have taken a turn towards the worst. It was not uncommon for 4 cylinder points to stay stable well past 7000rpm so the only reason to change to some other kind of ignition triggering device (even WITH points ignition is still electronic) 

 

I frequently have to try 4-5 sets of points now to find one that does not start to “float” and scatter the spark at 5000rpm and even lower. 6 cylinder BMW’s used the same points as the 4 cylinders and start to float even sooner.  Using something like the Delta Mk10 does not change this, it does lower the amperage through the points and as such they do not “burn” as quickly but it makes no difference when they start to float. 
 

We run Pertronix igniters in over 80% of our race cars ( not just BMW’s) and have never had a failure. They are also dead stable to well over 11,000rpm on the Cosworth BD and M12 BMW engines. I have also adapted them to work in  vintage 12 cylinder engines amongst others. 

Thank you for this first hand information. Are you using the simple, original type of pertronix igniters or the newer ones with more bells and whistles?

 

 

[Preyupy]

We just use the standard units. Most of the older cars just use a standard Blue coil and some kind of rev limiter(Pertronix,MSD, Micro Dynamics etc). They also work really well as a trigger for other ignition systems. 

[SydneyTii]

I’ve been running Petronix and a blue coil for 10 years no issue, good spark, runs well.

[Lorin]

45 minutes ago, Preyupy said:

We just use the standard units. Most of the older cars just use a standard Blue coil and some kind of rev limiter(Pertronix,MSD, Micro Dynamics etc). They also work really well as a trigger for other ignition systems. 

Thanks. My experience is purely street cars but mirrors yours. In 30+ years ive probably installed 20 standard pertronix units without failure. Great product. 

[tech71]

6 hours ago, Son of Marty said:

Plenty of people running pertronix and the blue coil,

My burning question to those who have..

Using pertronix and a blue coil, would I keep my stock resistor wire? 

Edited April 12, 2021 by tech71

[Son of Marty]

Bosch blue coil no resistor is needed.

[RainMoore]

8 hours ago, esty said:

i'd use the blue coil you have...the tach wire connect the same pace (-) terminal on coil

 

hot spark is a lot less money than Pertronix....i Hot Spark it on all my cars and have never had to replace one....yet

 

looking at hot spark. Definitely a good price! Pretty limited budget at the moment.

2 questions, does hot spark have the same automatic dwell as pertronix? I don’t have a timing light so that would be super helpful short term.

Also, hot spark requires “3ohm primary resistance”. When measuring this, it’s the resistance between the + and - on the coil, right? Not the large spark wire socket?

And if my coil is lower that that (I think it’s 1.5 ohm) how would I adjust this? A resistor or some type between the coil and the electronic points?

 

Thanks!

[TobyB]

Botch Blue should be 3ish ohms on the primary.  

 

I have put a resistor in- line when running a particularly cheezy VW-

style 'cool spark, dude' knockoff in the trencher.  It doesn't mind.

 

Likewise, I blew up one Pertronix by putting the wrong coil in-

other than that, like Byron, I've had them in lots of things,

and never had a problem.  They are an ideal trigger

for a MSD box, as well.

 

t

the MSD makes a great rev limiter.