Shadow83

I am doing a refurb to my 92 XJ. The coil was working fine but with 225k miles and almost 25 years on it I feel it is worth replacing as preventative and since it is apart. My ignition is stock but I was wondering if I would actually gain anything for the additional cost of using an Accel Super Coil over NGK OEM replacement?

jordan96xj

Super coils work by adding additional windings, which will produce higher secondary voltage (the voltage that actually jumps the spark plug gap and causes ignition). Your motor and ignition management was designed with the certain stock voltages in mind. The original designers had nothing to gain by having secondary voltage that was too low - and they could have adjusted the voltage to be whatever they determined was best. As poor ignition would have only left them with power and efficiency shortcomings. You have very little to gain by changing those things. The voltage of the spark is also only a small component of the burn quality at combustion. Temperature, pressure, and vaporization of the liquid fuel are the more important factors, and you won't be changing those.

Another practical downside is that the distributor cap, rotor, wires, and plugs were not designed around those higher voltages either. They will likely handle the higher voltage fine, but it increases the chances of problems on those components as well (spark jumping where it shouldn't, or finding weak spots in the wires/boots).

My opinion? Not worth it. There are other things I could spend my money on that would help my vehicle more.

tjwalker

Not only are they not worth it, I have found very poor reliability with Accel coils and the like. I will not install or recommend them.

The OEM style coil is all you need or want with the 4.0 engine.

papablista

jordan96xj <<< what he said, and if your is working fine w/225k it must be a good one, why mess with a good thing.

PatHenry

As part of my process of replacing all the engine management components with Mopar parts (while they're still relatively easy to find), I replaced my fully operational coil with a new Mopar. Interestingly when I got the old one off, I realized the old one had a few cracks around the mounting holes.
My Jeep ran smoother when I replaced the coil with a Mopar - so my old one was not quite as fully operational (more like 90%) than I had realized.

Like the others, I'd stick with OEM if you do decide to replace it.