Hmm, take the cap back off and check the center charcol contact. It may be cracked or tweaked somehow so the full energy of the spark isn't making it through the rotor.

Or the metal tab on the rotor isn't springy enough and not pushing against the charcol on the cap. Could be a wrong rotor thats slightly shorter as well.

It sounds like you narrowed it down to the distributor, but it may or may not be worth a try to take a wire directly from battery + to coil + . This will eliminate any bulkhead wiring or ignition switch issues because it provides the coil full power, and also temporarily bypasses the ballast resistor. You should have the stock ballast bypassed with the flame thrower as it has one built in (like a lot of the hotter aftermarket coils).

I know you said you get spark across the plugs but double check the gap just to be sure they aren't too wide open.

when you moved to pertronix, did you change your spark plugs? I'm asking cuz like all increased power ignition sys, the pertronix may kill your sparkplugs if they are too hot (a stock type spark plug is too hot for this high power systems)

I'll try to use new spark plugs. I didn't asked about the dist gear cuz you said that you replaced your dist, but it's fine? not chewed or marred?

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Juan, that doesn't make a lot of sense to me. The heat range of the spark plug has nothing to do with the strength of the spark or the type of system used to produce the spark. The phrases "too hot" or "too cold", as applied to spark plugs, refers not to the power of the spark, but to the operating temperature range of the electrodes. This operating temperature range is a function of spark plug physical design (length of the insulator nose relative to the shell). Also, the spark from an electronic ignition system is not "hotter" or more powerful than the spark from a standard ignition system, all other conditions being equal. There is a certain amount of voltage needed to jump a gap of a certain width under certain compression characteristics, and there's no such thing as forcing more voltage across the gap. (If the spark plug gap is increased, however, voltage goes up).

All name-brand spark plugs currently available are completely capable of handling the output of whatever ignition system is used with them in a street-driven application.

That said, often these days it is possible to install plugs of a somewhat colder heat range than originally specified, because today's gasoline burns cleaner than the fuel that was available when the car was new, so the plug tip doesn't need to run as hot to keep clean. By going to a colder plug, pinging can be avoided more easily. Too cold, though, and the plugs will still foul.

But no, I don't think the original poster's problem is "eaten" spark plugs.

dan, so basically you're saying that i.e. capacitive discharge produces the same amount of energy than, say, stock chrysler modules? that ain't make sense to me... I'll take that you never carefully inspected a "hot" spark plug turned into junk by a MSD unit.

triggered the same (take points for example) a stock type assy with condenser and coil doesn't produce the same spark neither the same voltage that produces a MSD ignition with a blaster 2 coil.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

The power (volts x amps) required to jump any given plug gap under any given conditions is constant. You cannot "force" more volts or more amps through the gap, for as soon as the power reaches that required to jump that particular gap, it will jump.
Basic principles of electricity.
I've inspected lots of spark plugs ruined in lots of ways. But, installing an MSD ignition and changing nothing else will not ruin a spark plug.

A "high performance" ignition system can supply greater voltage and/or current, but that doesn't mean that it will. The difference isn't what goes across the gap of the spark plug under ordinary circumstances, it's what happens under extraordinary circumstances.

Increasing the spark plug gap, increasing the compression, running a dirty spark plug (either through neglect or because some other thing you've changed allows the plugs to get dirty, e.g. a "big" camshaft left to idle)—all these things increase the amount of power required to jump the gap. A stock ignition system may not be able to provide that much power, with the result being a misfire. A high-performance ignition system has greater power potential and so will go ahead and fire the plug.

This is very, very commonly misunderstood, thanks in large part to the marketing tactics used in selling "high performance" (actually high performance POTENTIAL) ignition components.

one more thing: try to run a stock ignition system with 1.2 mm spark plug gap and then explain to me how come stock ignition has plenty of driveability issues with 1.2 spark plug gap if it produces "the same amount and quality" than a MSD system that runs perfectly smooth on the same conditions.

I'm no electronics expert, but what I posted comes from my experience: I ruined a set of spark plugs when I upgraded to MSD, then moved to a nice set of plugs 2 grades cooler than stock and had no problems whatsoever (fouling or misfiring or anything like that)

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

See above.

Dan is correct.

Aftermarket ignitions have the potential to send more voltage to the plugs, but unless something is done to the plug for it to require more voltage for spark to jump the gap (IE increasing the plug gap, increasing compression, etc) the voltage supplied to the plugs from any ignition system will be the same.

The real benefit of MSD systems are multiple sparks per combustion cycle, and the ability to provide the additional power required to jump a larger plug gap. In fact, MSD instructions recommend opening up your plug gaps over stock specs, for the very same reasons Dan explained above.

Question to the original post: What color is the spark you see when you check for spark? Is it a bright blue, or a dull whitish/yellow?

-S/6

You might've reversed the polarity in the coil. Are you sure you didn't connect the ground to the positive by accident?
Johnny Brougham

Dan

dunno why you're quoting my phrases chopped. I'm not saying that over a particular gap you can force more voltage or energy. That basic principle of electricity makes sense to me. Then you go on what I asked you in the first place: aftermarket, so-called hi energy ignition modules CAN produce more energy than stock components. Not that they will if they don't have to compensate any change like the ones you list for a spark plug to require extra juice to fire. This can't be achieved by ordinary stock components.
that's what I referref to when I wrote this:
Over stock specs any ignition is capable of doing the same, as you say, But when you change some things (as simple as gap, increased compression and "big cam" idling) stock ignition can't equal performance of any let's do not turn this into a game.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

So that I can respond to one point at a time. It's less confusing that way.
Terrific! Then we agree.
No game. The context here is helping the original poster figure out why his car was running fine and then suddenly refuses to start.

They're more of a dull whiteish/yellow, I would say. Could my coil be bad? In my experience they allways just stop working in a very dramatic way, but one never knows.

also, the cap and rotor look perfect, so no dice there.


thanks,
josh

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64 Dart 170 /6

That could indicate a weak spark. You've got points in it right now, right? Do you have a spare condenser lying around?
Not necessarily. They can look perfect and still have fatal faults.

I do indeed have a spare condensor, I will try that tomorrow after work.

Have you ever seen "scanners"? I mention that only because I believe that my head would explode if I found out that the new replacement cap that I bought (one of the first things I tried) turned out to be crap and therefor the problem.

thanks,
josh

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64 Dart 170 /6

I bought a new bluestreak cap that had a hairline cracked charcol piece in the center, and thats supposed to be one of the better brands.