Changing Plugs/Wires

[aggieEB]

I am thinking about changing out the factory wires when I install new spark plugs soon. I am going to go with the bosch +4s and Dead Link Removed. How difficult is it to change out the plugs/wires and what kind of tools would I need? I am somewhat of a newbie at this so tell me flat out if I should go have it done instead.

 

[spiper]

Do a search of the site for this. All you need is a 5/8" deep well socket with various extensions and a decent boot puller for the wires. It is fairly easy to do, the passenger side plugs are easily reached up through the wheel well.

 

[addkev]

Me personally, I would research the +4's first. They are high performance plugs, and folks that have put them into a regular engine, have had quite a few problems. You should be able to find quite a bit of info here in the forum. The Jacob's wires are awesome. Good choice there, I would just go with either Motorcraft Platinum, or just Bosch Platinums and save the money.
Also, it is much easier to get your pass. side plugs, by removing the wheel and going through the fender well. Some folks have said it took them an hour. Me personally, it took closer to 4 hours. Check out this thread.

http://www.explorerforum.com/forums/showthread.php?threadid=41968&highlight=PLug+wires[/URL]

 

[Kontrol-Trak]

IMO those +4 plugs are nothing but waste of money. I have regular bosch platinums and they work just fine.

 

[aggieEB]

Thanks for the update on the plugs.

If I have the plugs changed on the next tune up, how hard is it to change the wires? Is it pretty simple pulling and plugging to get those bad boys in there or am I going to have to go through the wheel well with those as well?

 

[addkev]

The wires are easy.
I didn't mean to discourage you from doing the work yourself, there isn't much more satisfying than doing your own work to your truck. I just wanted you to set aside enough time and be prepared, it was never hard, I just had to be smarter than my truck.
Do it yourself, save the money, get some cheaper plugs that are just as good and make sure they are gapped. And you will be satisfied.

 

[jimmiecakes]

THE SKINNY ON SPARK PLUGS.....

The 4.0 has three negative firing plugs and three positive firing plugs (the spark jumps from centre to ground on one bank and ground to centre on the other).
Regular platinum spark plugs have platinum on the centre electrode only. Motorcraft markets a double platinum but, unfortunately, the coverage isn't great.

Since the platinum is really only helping on three of my spark plugs, I opted for and will continue to use normal, blah spark plugs..... until someone offers double plats to fit mine, anyway.

There's no magic in spark plugs and I find it hard to believe that folks will spend 10 or 15 bucks for any of them.

 

[JDraper]

Jim's right, from an engineering standpoint, the +4's really don't give you any performance advantage. The spark always takes the path of least resistance, therefore you only get one spark each time it fires no matter how many electrodes you have. It's a marketing gimmick. Use a set of conventional platinum plugs and save the $$ for something substantial.

 

[addkev]

The 4.0 has three negative firing plugs and three positive firing plugs (the spark jumps from centre to ground on one bank and ground to centre on the other).

Since the platinum is really only helping on three of my spark plugs, I opted for and will continue to use normal, blah spark plugs..... until someone offers double plats to fit mine, anyway.

This true from the factory, but once you replace the plugs they are firing the same.

There's no magic in spark plugs and I find it hard to believe that folks will spend 10 or 15 bucks for any of them.

I agree with this, too. I bought my Bosch Platinum's from Pep Boys for $2.55 each. Anybody spending more than $5 for spark plugs would have to explain that to me.

 

[jimmiecakes]

Looking at the ignition system, two plugs share one coil.... spark for one sharing plug jumps centre to ground - for the other sharing plug it will always be ground to centre. This will never vary. Having platinum on the centre electrode of the negative firing plugs will never, ever by any stretch of the imagination, provide any benefit.

I live in Canada.... you can't buy a brand name copper plug for $2.55 here, let alone a platinum.

 

[nosaj122081]

Originally posted by jimmiecakes

I live in Canada.... you can't buy a brand name copper plug for $2.55 here, let alone a platinum.

GEEZ!!! I buy Autolite coppers for my Mach for 99 cents each! Hehe, you send me a 2 bucks a plug and I'll mail you some cheap US plugs ..

 

[addkev]

I have never had it explained that way. My understanding, from other postings here on the board, was that it was a money saving issue. Ford used the cheaper plugs for 3 cylinders. $.20 x 3 plugs x 1,000,000 Explorers...adds up.

 

[wallygetsit]

In ignition systems you want the least amount of resistance as possible. This is why I only purchase copper spark plugs. Copper is a better conductor of electricity than platinum. The advantage of platinum is their longevity. Before I researched into this I had Platinum+4's in my Explorer. Saw and felt no better performance over the stock plugs. Sent them back to Bosch and got my money back. I purchased Autolite coppers and installed them. They have been everybit as good as stock. I do gap my at .065". I am not a big fan of changing the back two plugs on the passenger side. I always have to take off the inner fender well cover.

 

[Grateful11]

I've replaced the plugs twice on my 91, Bosch Platinums the first time and Bosch Super Plugs (std. core), the second. To be honest I can't tell a bit of difference between either as far as mileage or performance. I think I paid .89 each. I also went with the best Bosch wires they had but one of the clips cracked as soon as I snapped it in and I had to take it back for a replacement. I figure if I ever have to unclip them anything they'll probably all crack. Cheap plastic.

 

[Rhett]

wallygetsit... 0.65 is quite a large gap there. At least on the 4.0 OHV the recommended gap is .054 but I don't know what it is for the SOHC. What wires do you run?

 

[wallygetsit]

The gap is large, but I like to tax the ignition system a little to get a larger spark. I use Motorcraft wires from the parts department at the local dealership. Funny, but the aftermarket Motorcraft wires are 8MM and the stock Motorcraft wires are 7MM.

 

[jimmiecakes]

Any particular reason you want to be harder on your parts than necessary? Increasing required voltage increases the chance of misfire and may break insulation down sooner than normal. I don't recall seeing any studies on performance gains arising from increased gaps.

 

[pax]

I just replaced mine with regular Bosch platinums a month ago. The wires were still good, I didn?t change them. It took me about 2 hours. It?s not that hard to do. I had to buy a boot puller to get the stubborn boots out of the 3 spark plugs on the driver side. I can?t get enough grips from my fingers to get them off the plugs since the EGR rail is on the way. I had no problem with the 3 on the passenger side. Go for it.

 

[Rhett]

jimmiecakes I don't know about any studies or tests or anything. I do know that a lot of racers will open up the gap more, and some racers or draggers even "side gap" their plugs, which is shaving off part of the electrode.

Side gapping can foul the plugs very quickly and thus only racers do it--it's not practical for every day driving-- but there must be some performance benefit or they wouldn't do it I would guess. Anyway I suspect there is a "point of diminishing returns" when it comes to opening a gap...as in if you open it too much, you'll get bogging, short plug life, and a struggling ignition.

Way back when I bought my wires I talked with a Jacobs tech about gapping. In short the discussion boiled down to a couple of things, like the strength of the Explorer ignition, which seems to be above average from what I understand, and, the use of aftermarket wires, etc. allowing "safe" operation at about .05 over stock gap. I have been running a gap a little over for 1.5 years now and it hasn't affected driveability. I could probably re-gap to .054 and not notice anything, but I really don't want to bother with pulling the plugs, if you know what I mean. heheheh

 

[jimmiecakes]

I don't know any racers (personally) that side gap their plugs... man, that would take a lot of bending. However, most racers "index" their plugs... getting the ground electrode out of the way of the mixture. I've seen no studies that can verify the benefits, but if it can't hurt....

Increasing the gap, however, may present more of the "working fluid" to the spark, but it can increase ionization voltage to the pont where external insulation can break down (giving intermittent misfires,,,, dropping cylinders, if you will) or reducing spark duration which will result in LESS mixture being exposed to the spark, resulting in misfire. Increasing the voltage required to ionize the spark gap can also be detrimental to the coilpack.

Without a solid understanding of the effect of magnetic fields moving across conductors, it can be difficult to appreciate what really happens in an ignition system. This is a very, very complex interelation of events and side effects. Forward EMF, back EMF... collapsing magnetic fields inducing a voltage that creates a magnetic field that induces a voltage that creates a magnetic field that induces a...... You may not notice it in normal operation, but the engineers have spent many hours in producing a combination that will both please the customer, exhibit satisfactory emissions standards and and yield a production run that will appease the CAFE gods.

We wont mention the diagnostic nightmare that a "customized" spark plug gap can enhance. It's your car and your electronics... but even after 30+ years making this my living, I fail to see the sense in "taxing" my equipment as a standard operating parameter.