Re: TFI voltage
My parts guys still slip up and say, "...You want fries with that?" [img]/wwwthreads_images/icons/shocked.gif[/img]
I always said, "Full 12 volts" for the guys that had the factory Motorcraft/ DuraSpark ignition.
The resistor wire was already built into the harness, and it just confused a lot of people if I referred to current reduction via a resistor they couldn't see.
If you Jeep is a '78 through '90, it has the resistor wire.
If it is a '72 or older, it has a resistor in the harness somewhere, but that was a breaker point type ignition.
I haven't done the research on the Prestolite years to tell if they had a resistor or not...
(That was such a piece of crap for an ignition that even points were more reliable, so why waste any more time on it?)
If you haven't had any problems with your upgrade yet, you probably won't.
If you want to add a resistor, use a Chrysler 'brick' type (porcelain type, about 3 inches long) and just plumb it in the coil supply line. You are looking for a total of about 1.35 Ohms, and your (assuming) TFI style coil is about 0.45 Ohm, so you need about 0.90 Ohm up to 1.50 Ohm resistor.
If something gives, it will be the power transistors in the DuraSpark module...
(So carry a spare if you don't already... Or put the resistor in and don't worry about it)
I can tell you right now, if you are feeding that coil a full 12 volts, using 18 Ga. wire or larger, you have one HOT ignition!
That's a good reason to switch to MSD!!!
Tell your wife I said so!
MSD modules are the PERFECT Christmas gift!
Want me to e-mail her with gift ideas??
MSD A or MSD 6T modules... Always the right size, always the right color, and never returned!
The perfect holiday gift for those hard to buy for guys that don't know a damn thing about designer clothes!
(Think she'll go for it? [img]/wwwthreads_images/icons/wink.gif[/img] )
So many cats, so few recipes...