84-99: Champion copper

00-01: NGK. They hold up a bit better to the waste-spark distributorless ignition on the 2000 and 2001. Champions are okay, but I recommend the NGK.

Stay away from Bosh spark plugs for the 4.0 I love Bosch products, but there are more than a few reports of mysterious misfires with some (not all) using Bosch plugs, which clear up immediately upon the installation of Champion or NGK.

ALWAYS verify gap with every plug installed! Needs to be .035. Gapping plugs takes very little time.

 

When changing plugs, always start them by hand. You should be able to thread quite a bit in by hand before using a ratchet. The PO of mine stripped out the first couple threads on one of the current plugs (I don't know about the head, hopefully not). Definitely get a Chilton/Haynes manual, they are extremely helpful. I use mine all the time. Good luck!

 

I use these in my 89

 

What brand of muffler bearings are best? Looking to improve my MPG and gain around 100HP??

 

This thread is two years old, *******.

 

Muffler bearings are special order now no longer carried in any store...

 

JY Idem for sure. "Back in the day", I used to joke about "the muffler wiring". Low and behold, now we actually have it! (02 sensors).

 

I've always changed the plugs in all my vehicles myself, as it's easy to do {in most vehicles] but also a satisfying thing to do. I always have bought the newest plug out there, especially the ones that pronounced performance gains. I've been through Split-fires, E 3 's, copper, iridium and so on. Unless my vehicle was badly in need of new plugs I never really noticed any difference. Champion, Autolite, Mopar, NGK, Iridium, copper, double or single precious metal and so on. As long as your ignition system is working as it should, a spark plug is pretty much going to have same spark intensity as any other one. You shouldn't expect miracles, or even a noticeable performance increase with any modern spark plug.

 

Whoah!

I know it's an ancient thread, but since there's bad info here, I'll take a moment to address it, lest future newbies be mislead.

The coil has NO moving parts. There is no "spinning" copper wire.

The only thing that moves is a magnetic field. When the distributor contacts break the flow of current through the primary coil, the magnetic field surrounding it collapses. This collapsing (moving) magnetic field cuts across the secondary windings, which induces a current in the secondary. Because the secondary has many more turns of wire than the primary, the voltage is increased (and the current is decreased).

The principles are exactly the same as an alternating current transformer like the one that provides AC power to your house. The only difference (besides size and the voltages used) is that the AC transformer uses alternating current to move the magnetic field, while your car's ignition system uses the making and breaking of the points to move the magnetic field.

Look up any Youtube video on how transformers work if you want to know more.

 

Yep what he said. "academic" difference is that the primary flow is cut by the puter' controlled ICU. Potato Patato.

 

Whoa it sounds to me he meant to say wrapping instead of spinning.

 

I bet you are indeed correct there Crawdad. I hadn't caught that.

In any case, a good excuse to talk, (more), about a collapsing primary field!

 

Oh, yeah. My bad. I'm thinking old school!

 

2 posts.....

 

Hell of a post dig for a 2 poster...