Do our ignition systems require a ballast resistor?

[jonnymopar]

I'm having some odd in-boost spark issues lately and I'm still trying to chase it down. I happened to glance at the instructions for my MSD Blaster SS coil that I've been using for 42k miles now. It says to use a ballast resistor on non-current-limiting systems. Does that apply to us? I'm running a 2.4 on a SMEC.

[tryingbe]

What is the odd-in-boost issue? At boost level? Try a smaller gap?

[Ondonti]

Does not apply. That install is probably with an older mustang ignition in mind.

[tinyturbo]

If it is an oil filled canister type coil than it does need a ballast resister, the canister must be mounted very close to vertical also according to msd tech

[contraption22]

Agreed. All the Chryslers I've had with canister coils had a ballast resistor.
Also, I've had bad luck with MSD coils. Try a stock one.

[jonnymopar]

What is the odd-in-boost issue? At boost level? Try a smaller gap?

When I take it up past 12psi or so, it starts misfiring. Idling, putt-putting around town, and lower boost, it's completely smooth. I can't really say that it's a plug gap because it's an all-of-a-sudden problem. Saturday night I was out terrorizing people and 20psi was fine. I experimented with plug gap years ago when I first got it together, and .025 seems to work well with my setup:

-1st gen 2.4
-distributor on the intake cam
-Blaster SS coil
-NGK V-power copper plugs (just put new ones in yesterday gapped at the same .025" as the old ones - identical results)

I've ran this for years without any major issues. I've still got some investigating to do before I get mad though. I've got the coil on my desk with me and both primary and secondary resistances look reasonable. I don't see any physical damage either.

Agreed. All the Chryslers I've had with canister coils had a ballast resistor.
Also, I've had bad luck with MSD coils. Try a stock one.

I do have plenty of stockers around! If that's it, I'll have to come up with some other mounting. I'm not so keen on mounting an oil canister type coil on the engine.

[supercrackerbox]

If it is an oil filled canister type coil than it does need a ballast resister, the canister must be mounted very close to vertical also according to msd tech

Agreed. All the Chryslers I've had with canister coils had a ballast resistor.
Also, I've had bad luck with MSD coils. Try a stock one.

Are you guys sure you're not thinking of the condenser that was mounted on the older canister coils? A ballast resistor is used on pre-HEI ignition systems that still use breaker points. They limit the power to the points to ~7 volts in order to keep from burning the points up. With the advent of HEI ignition modules (and whatever Ford and Mopar called their equivalents) around 1973, breaker points and ballast resistors became obsolete because factory ignition systems were now able to handle the full 12 volt power load.

[contraption22]

Eh maybe you're right. Lol

[shackwrrr]

Get a stock coil. That blaster coil has much less output than the stocker. Also, no ballast resistor required, the driver in the smec limits current automatically.

[jonnymopar]

I've never seen anything next the stock coils other than the little condenser, so I was kinda confused by that. I'm pretty sure the condenser is nothing more than a heavy-duty capacitor. The ballast resistors I've seen were either aluminum extrusion housed for heat, or a wirewound ceramic resistor mounted to a heat sink.

Get a stock coil. That blaster coil has much less output than the stocker. Also, no ballast resistor required, the driver in the smec limits current automatically.

Where can I find specs on a stock coil? Also, did TBI and turbo cars get the same coils?

[jonnymopar]

Huh, well I'll be:



I whipped up a crappy coil wire and half-assed a mount onto an unused stud on the intake. Whaddya know... tire-frying boost! I wonder what gave out in that MSD coil. It's been in there for a pretty good while now.

Questions:

- How well do the later-model coils mounted to the engine work when compared to the old-school oil canister coils?
- Is anybody using the stock canister-type coil in the original location while using the distributor on the head? That setup makes for one LONG coil wire.
- Anybody know of any better coils that I could mount similar to where my MSD coil is now?

Thanks!

[shackwrrr]

Probably the best factory coil is the e-core coil on the later models. I think they are near 55-60kv. Those blasters real world are somewhere like 26-30kv.

[turismolover22]

Chrysler and ACCEL coils have an internal resistance of 1.4 something, IIRC. The MSD coils have an internal resistance of .07 ohms. So a ballast resister is needed to increaceresistance to the correct values. Stock coil or Accel super stock is preferred, many people Ive seen use the MSD have issues, when ran without the ballast resistor.

[supercrackerbox]

I run a later-style epoxy cored coil on my Charger and I think it works great.

[jonnymopar]

I absolutely hammered on this car on the highway going to work today. I swear it's smoother in the 5000+ RPM range with the half-assed stock coil setup on it. I guess it's time to grab a later-model coil.

Would one of these work?: http://shop.accel-ignition.com/ignit...by-jacobs.html

[turismolover22]

I would start with this one - http://www.jegs.com/i/Accel/110/1400...kaAq2i8P8HAQOr this one - http://www.jegs.com/i/Accel/110/8140..._m0aAgn78P8HAQ

[Dr. Johny Dodge]

the accel super stack works - I used one for a long time on one of my old TD's

I've also used the flat grey efi ford / gm accel coil - Idono the part number for that but it has fins running across it on an angle - it too may be better with a resistor - again Idono , never tryed it with one

[jonnymopar]

Sweet! I didn't know there was a Screamin' Demon coil for our cars: http://www.summitracing.com/parts/dui-31728/overview/

I've been running one of these (well, the DIS version) on my Neon with a set of Crane wires for years and it's been great. I might give this one a shot.