[nicksbar]

Hey guys...I'm looking at upgrading my ignition system to a TFI.

http://www.jeepz.com/forum/engine/16904-tfi-ignition-upgrade.html

My question...would this coil work (http://store.summitracing.com/partdetail.asp?part=MSD-8202) instead of the ignition coil it states in the jeepz.com link above?

I have it lying around here and for the life of me i can't remember where i used it

[yellow2kgt]

Yes, it will work. Just make sure you use the factory coil wire(resistor) to power it.

[nicksbar]

looks like there is missing something though....the MSD coil has a female top...the other has a male.

What do you mean "use the factory coil wire(resistor) to power it."

[yellow2kgt]

The factory coil is powered by a resistor wire that cuts the voltage back to about 7-9volts instead of 12 volts. Supposedly without it there is too much current for the module to live. Some folks claim the original ignition modules(OEM) could handle the higher current but the cheap parts store ones seem to live a short life without it.

[nicksbar]

the msd sites mentions this warning....

WARNING: When using the Blaster Coil with a points or stock style distributor, a 0.8
Ohm ballast resistor must be installed in-line of the positive wire. Failure to
use a ballast resistor could result in personal injury or component failure.

Is this required on a YJ? Or will the YJ Factory coil wire connect direct ok?

[yellow2kgt]

I believe the factory resistor wire is 1.35 ohms. So it should actually cut the voltage more then .8 required. So you should be OK using the factory coil power wire. Just make sure you don't cut the wire. If you shorten it you are technically reducing it's resistance.

[timatoe]

Originally Posted by nicksbar

the msd sites mentions this warning....

WARNING: When using the Blaster Coil with a points or stock style distributor, a 0.8
Ohm ballast resistor must be installed in-line of the positive wire. Failure to
use a ballast resistor could result in personal injury or component failure.

Is this required on a YJ? Or will the YJ Factory coil wire connect direct ok?

I used to run the MSD Blaster coil with my stock setup before doing the HEI and had no problems and installed it as a direct replacement to the stocker with no wiring changes.

[nicksbar]

anybody else done this upgrade....

[lah2420]

I did it a few years ago. I used all the Ford parts and haven't had any problems with it.

[4.7stroker]

Hundreds of people have done the TFI upgrade, it even works with the stock Jeep coil.
Without the resistor the module will over heat (ask me how I know) but after it cooled down and I installed a balast resistor all was fine.

Dwayne

[nicksbar]

So what was mentioned above is false?
Regarding the resistor wire from stock coil to MSD +

Originally Posted by 4.7stroker

Hundreds of people have done the TFI upgrade, it even works with the stock Jeep coil.
Without the resistor the module will over heat (ask me how I know) but after it cooled down and I installed a balast resistor all was fine.

Dwayne

[yellow2kgt]

No, he was saying that without the resistor his ignition module overheated. He added it back and all was fine. However, instead of using resistor wire he purchased a ballast resistor(older cars used to have them mounted to the wheel wheels or firewall) instead. They both accomplish the same thing. It does not matter what coil you use you need the resistor inline with the 12volt terminal to cut the current running through the ignition module. As long as you don't cut the factory coil wire(putting on a different terminal is fine) you should be fine. If you cut much out of the resistance wire you are effectively reducing it's resistance.

[lah2420]

Originally Posted by yellow2kgt

No, he was saying that without the resistor his ignition module overheated. He added it back and all was fine. However, instead of using resistor wire he purchased a ballast resistor(older cars used to have them mounted to the wheel wheels or firewall) instead. They both accomplish the same thing. It does not matter what coil you use you need the resistor inline with the 12volt terminal to cut the current running through the ignition module. As long as you don't cut the factory coil wire(putting on a different terminal is fine) you should be fine. If you cut much out of the resistance wire you are effectively reducing it's resistance.

That's basically what I did too. I spliced into the existing wires right at the factory coil connection to run to the new coil.

[smitkev2]

I've been reading this and I am very interested. I just replaced the factory coil. Can I use this and just buy the distributor parts, wires and be done? Or do I need the Ford style coil and splice wires to fit? Thats the part i'm a bit confused on. If its answered above I missed it.

[yellow2kgt]

The factory coil will work fine. It just does not have the higher output that the TFI(square) coil does. At least you would be upgrading to the larger cap. That helps by spreading the plugs apart to keep cross firing down between the terminals inside the cap.