I have a 2003 Durango 4wd 4.7 V8...Does it have spark plugs??? I was informed by a local auto parts store that it did not and that it had individual coils instead. I think it was BS but went with it. Second if it does and I'm guessing it does...what would be a good type of plug to use? i.e. platinum, iridium, etc.

 

yes it has spark plugs(its NOT a diesel engine), you need to find a new auto parts store

it does NOT have spark plug WIRES, they plugs are installed underneath the coils, and replace with copper core champion plugs of OEM type ONLY make sure they are gapped to .040 and your truck will love you long time

 

Meaning;

Each cylinder has a single spark plug for a total of 8. There is a single coil over each spark plug for a total of 8. The coils are called "coil overs". There are no spark plug wires as the coil is directly over the spark plug.

You simply pop the coil off and replace the spark plug. You should get the cheap $2 Champion Copper spark plugs (OEM) and gap them at .040 before installation.

 

What is the benefit of the the coil overs vs traditional setup? And why on 4.7's but not on 5.9's?

 

I've never heard of COP (Coil On Plug) refer'd to as "coil overs". I usually install coil overs as part of a suspension.

The benefit to COP is that it gets rid of the spark plug wires. Wires break down over time, hence the need to replace them at tune intervals. With no wires to break down, you have more consistent and usually stronger spark with ever plug firing event.

For hotrodders it can also help clean up the engine bay. I plan on using COP at some point in the not too distant future in my Datsun, as both an experiment and to clean up the engine bay.

If you compare COP to an ignition system that uses a dizzy (distributer), the COP set-up has one gap to jump instead of 2 or 3. In a dizzy set-up the ignition energy has to be passed down the coil wire to the dizzy, where it then connects to a "button" in the cap of the dizzy, which then sits on the middle of the rotor, where there is a very small gap, the rotor then transfers the energy to the end of the rotor, where it has to jump the gap to the post that is connected to a spark plug wire leading to each cylinder, where the spark has to jump yet another gap to ignite the air and fuel mixture.

COP eliminates the coil wire, dizzy, dizzy cap, dizzy rotor, and spark plug wires, so that the coil has only one gap to jump to ignite the air and fuel mixture.

Another benefit of COP is that the charge dwell time can be longer, since each coil will fire less often than a dizzy system, creating a hotter spark. Timing can also be controlled much more precisely with longer or multiple spark events, much more easily than a dizzy set-up can.

 

Makes since. So why didn't they use COP on the 5.9L? Do the newer generations of Durangos use COP in the larger engines now?

 

Isn't the 5.9 an older engine?

If it is, it's most likely due to not having the technology early on, and like most companies that plan on releasing a newer engine, they would just carry over the old design until the new one is released. ChyCo seemed to do this a lot in the early 2000s. I worked on so many of what seemed like the same year Caravan installing remote starters and some would have DIS, others would have a dizzy.

I haven't looked at a 4.7, since I only recently bought my (first) Dodge and only because it was a great deal, not because I was looking, but my 3.7 uses COP. I would imagine that the 4.7 does as well, but Google/BING/Dogpile/etc, would likely be able to inform you better.

 

the 4.7 is COP that is correct, the 5.9 is an old (very old) engine, the block is bascially unchanged since it was used as a carb'd engine. they dont use the 5.9, or the 5.2 (or the 3.9 for that matter) in new vehicles anymore, and yes the 3.7,4.7,5.7,6.1, and the soon to be released 6.4 will all use COP, idk about the 3.7, but the rest of them currently have two spark plugs per cylinder.

 

3.7 has 1 plug per cylinder, if it had 2, I'd sell my truck. There's no need for dual plugs on a production vehicle as far as I'm concerned. The cylinder pressures aren't high enough to need that kind of amperage to light off the air/fuel charge.

 

the way the two plug sets up are done (they didnt go 2 plug/cylinder on the 4.7 till 08 iirc) is for emissions, the second plug fires on the exhaust stroke to burn any remaining unburned fuel that is left in the cylinder, its not two plugs firing at once to ignite the mixture