Had my slug tuned up on Friday. Runs great after Autolite 764's, MSD 8.5mm plugs, fuel filter, PCV valve, and tranny fluid change! Now I just gotta clean the K&N. :-)
We found the right-hand cylinder head had four different spark plugs than the left one. There were PG's in the right and P's on the left. I bought the car at 24,000 miles and had never changed the plugs before Friday. What would be the reason to change just four plugs? Is this strange or could there have been a problem with the engine before I got it? I'm thinking maybe the intake blew but not sure if that would be a reason to change a few plugs.
For uses plugs with platium plating only the required electrode for each bank. One side has the center electrode plated, the other has the one that gets moved to set the gap (can't think of the name atm) plated. It's just ford squeezing out every last penny.
I'll second Brents reply..... Those cars using waste spark ignition systems came from the factory with platinum on only the electrode that mattered for that bank (one plug being positive electrode 'firing' and it's running mate being ground electrode 'firing').
Motorcraft replacement plugs are double platinums... i.e., both electrodes are platinum tipped. Because of the ignition system characteristics, replacement single platinum plugs (those with platinum on only the centre electrode) are a wast of money.
What you found is about as normal as you can get. Side note for those with COP ignitions..... you will find platinum on only the centre electrode....
So you're saying Ford puts two different kinds of plugs in at the factory?
Two mechanics told me Platinum are better than Copper. I said I heard different and that Platinum were not worth the money so I wanted Copper. Mech says "Well I disagree but we'll put whatever you want in there." LOL!
Because of the ignition system characteristics,
What is your opinion of Autolite 764's? They were cheap. I don't care if I have to replace them in another five thousand miles.
Actually I forgot to mention that the plugs on the right were NEWER. Still normal?
I have used Autolites in the past with good success..... You'll find that the copper electrodes will erode somewhat quicker than the platinum tipped.
As I've said before, single platinum plugs are a waste of time and money in a wasted spark system. Let's follow an electron as he/she completes one lap of the circuit. When the control circuit and the laws of physics say "GO", our intrepid electron races out of the ignition coil and speeds down the spark plug wire to the centre electrode of the "positive" plug. We'll assume that the plug gap is already ionized and our electron can leap from the centre electrode to the ground electrode. From here, he/she find's the way from the cylinder head, through the block, through the other head and finds itself at the ground electrode of the first cylinders running mate - you read right... at the ground electrode. Our electron now leaps across that gap, heads up the plug wire and finally get's home safely to the coil from whence it came. A little over-simplified, but basically that's how it goes.
Platinum plugs are a good investment and they do, generally last longer than coppers..... as a rule of thumb, I use whatever came from the factory. As for the plugs on the right being newer...... I'd be interested in how that was determined. We have to remember that the spark on the PG plugs jumps from the ground electrode to the centre electrode. This will leave different patterns of erosion than what we see on the PP side. If we had a couple of these plugs brand new, we'd notice that the PP plug looks just like an ordinary platinum spark plug. The PG plug is a different story..... the centre electrode looks like the electrode in a copper plug and we notice a platinum tit on the ground electrode pointing at the centre electrode. We need to avoid being lead astray by the different appearance of the two plugs.
Lastly, I have yet to find a source for the PG plugs - even your friendly Ford store can't get them and will supply double platinums instead.
Hopefully you also had the transmission pan pulled and put a new filter and gasket in there. The fluid-only changes are not a substitute for this, unfortunately. Within a few thousand miles, that new fluid will only mix with the crud in the pan and filter, and will be just as contaminated as the stuff that came out. And of course, I recommend the $7-buck/qt. Mobil One synthetic ATF, a product that few Skippy Lube places carry.
OEM specs call for 2 different kinds of plugs on 4.6's, because of the way the ignition is set up. One bank's plugs fire from positive to negative, the other from negative to positive. OEM replacement specs call for double-platinums.
Not surprised that the mechanic differed with your opinion. Platinum plugs are spec'ed because they are marketed as having a longer service life. My experience with inexpensive copper-cored spark plugs have demonstrated to me that these claims of platinum plug superiority are nothing more than marketing bullshit.
The fluid-only changes are not a substitute for this,
I didn't really want to spend that much, so we used a Valvoline oil...not sure which one. Maybe I trust my mechanic too much? ;-)
You use copper then?
One of the mechs told me platinum were better for longevity AND performance. This is contrary to what everybody else has been telling me.
My
The platinums we took out of my car were shit, but they had been in there for 77,000 miles. I guess that's amazing? I doubt the copper will be in there that long. But at $5-$10 per plug it isn't worth it to me unless I hear something grand I can believe about them.
From my experiences, plain old copper plugs work better and last nearly as long as their higher-priced platinum cousins. I'd rather spend the money on synthetic fluids.
Well, I work for a Ford store now......... that might colour my ideas a bit but I have never had a problem with a Motorcraft plug.... other than they don't offer a double plat for my '92 Exploder. For your application, the Motorcraft store would supply the double platinums...... after 60K miles or so, you would get a real good idea of the wear patterns between left and right plugs. Yes, the factory plugs bear the Motorcraft name and logo but the exact same plugs aren't available over the counter. It would be too easy for a DIYer to confuse what plug goes where (hell, be too easy for some techs to screw that up) and that would only offer the ambulance chasers a new venue.
Those that change thier plugs every other oil change are either changing plugs way too often or not changing oil often enough 8^)
If it makes you feel any better, I can recall the first time I came across the "wonky" plugs - the old guys eyebrows about shot straight up and I really figured I was on to something...... then common sense settled in and I figured the deal out without making that embarrassing phone call that would have made me look like "el Dorko Mundo"..... I can do that quite well on my own, without Fords help.
Enjoy your ride, Cindy..... there's nothing sinister about the two different plugs in the motor. All they do is save Ford a few cents a car on the assembly line....
I hope Cindy had only the filter changed in the trans...... the reusable gasket from Ford is far superior to the cork gaskets offered in transmission filter kits.
Ford does not offer a gasket with replacement filters for their modern transmissions - first off, you can't fold them up and expect them to work.......... second, cork, rubberized cork, and rbber just can't perform the way these puppies can - and you can take that to the bank....
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