[MoparJeff]

I have a 1992 2.5 non-turbo automatic. Before parking it (6 years ago) I ran OE spec Champion RN12YC plugs. Standard, copper, cheap and still available. Pulled them today (about 5,000 miles on them before parked) and they look pretty good, nice even brown color, no corrosion, etc.

Now that I am working to put the car back on the road and have to replace a LOT of stuff, what are you running? Should I be looking at some of the newer platinum or iridium plugs that are availible? Any gains over the $1.99 standard OEM spec ones?

 

[ImperialCrown]

Not really. The Champion RN-12YC spark plug recommended in the owners manual and underhood emissions label is still the best plug chosen by the Chrysler engineers for your engine under extensive factory laboratory research conditions.
Copper still offers the best burn. Platinums may last 3 times longer, but some applications experience misfire and yours are easy to change anyways. Iridium is overkill, you won't experience any performance benefit.
Beware of spark plug marketing horsepower and fuel economy claims because 99% of that is all it is...marketing.
Good cap,rotor and wires are important.
If the car has sat for 6 years, a bottle of Techron in the fuel tank can't hurt and I would be more concerned about what the inside of the tank, pump, lines and injector look like after that amount of time.
Change the oil, filter, coolant, ATF, P/S and brake fluids as well after sitting that long just to be on the safe side. Fluids do age, even without use.

 

[MoparJeff]

Thanks, kinda what I figured but worth asking... there has been a lot of change, marketing or otherwise, since the shop manuals were written in 1992

Covered a lot of this in my "barn find" thread in the main forum, lots of good advice consistent with yours.

Tank, pump, lines a big concern because I didn't do much if any prep to park it. The plan wasn't to to have it sit this long but.... it did. Will drain tank and put fresh fuel in before the big start up. But that is awhile away, lots to check/clean/replace before that.

 

[Doug D]

Yep, I always ran Champion coppers or Autolite coppers in the 2.5's I had. I logged over 800K miles with three 2.5 engines.

At least the plugs on those were easy to change out compared to my Ram's 5.7L Hemi. On average it takes 3 hours to change out 16 plugs and no, platinum is not recommended. Coppers only.

 

[B10alia]

+3 (or 4) on the Champions. These motors actually run worse with other (more expensive) plug brands. On the topic of ignition systems, engines absolutely EAT ignition rotors, and char the wire ends pretty fast.

 

[raymondo112]

Champions use OE recomendation for any car always, autolites and other brands should only be used when you absolutely have no way to get the OE part and you have to get the car running, that's should be the only time, plugs have resistors in the porcelin insulation inside, each and every brand has a different style resistor, some bigger some smaller, Chrysler designs their engines to run off champion plugs and the engineers for their engines design them to be able to run on the rate at which the resistor wears so using a different plug can leave things out of sync, and it may not be recognizable at first but in time and as mileage increases you will see and feel the difference in performance, Chrysler designed the motors for optimal performance and economy already in mind, remember, motor trend and such magazines test their cars against their rivals from GM and other counterparts and they tell the good and the bad, and they also test the performance, so it doesn't make sense to leave anything on the table you bring it all from the get go and that's what the manufacturer does because they want the product to be able to perform at its best under and at load at all times.

So remember the guy the engineered your car and engine makes six figures a year for a reason because he knows things you don't so why try to reengineer your car when you never been to engineering school, if you are trying to extract power and performance you go hard or go home, meaning there is no performance gain in plugs and wires that are worth mentioning, the guys that run quarter mile strips can tell you it starts from the bottom up and costs money lots of money and it aint easy, so don't get ahead of yourself if you build a performance engine then it might call for something different but on an OE engine it runs best and performs best on OE parts even most parts at the parts store have to meet or exceed OE specs. Performance is different and therefore is something to leave to the people that know it best or else you are slapping in parts and hoping for miracles and probably not achieving anything worth talking about, when you build performance engines you are reengineering it for something different than what it was normally built for so that is why you need to know what you are doing or bad things start to happen or it just performs badly.

 

[MoparJeff]

Thanks for the input.

FYI, no one is trying to re-engineer anything, just checking to see if anyone had any recommendations of something other than OEM.

 

[Doug D]

Champions use OE recomendation for any car always, autolites and other brands should only be used when you absolutely have no way to get the OE part and you have to get the car running, that's should be the only time, plugs have resistors in the porcelin insulation inside, each and every brand has a different style resistor, some bigger some smaller, Chrysler designs their engines to run off champion plugs and the engineers for their engines design them to be able to run on the rate at which the resistor wears so using a different plug can leave things out of sync, and it may not be recognizable at first but in time and as mileage increases you will see and feel the difference in performance, Chrysler designed the motors for optimal performance and economy already in mind, remember, motor trend and such magazines test their cars against their rivals from GM and other counterparts and they tell the good and the bad, and they also test the performance, so it doesn't make sense to leave anything on the table you bring it all from the get go and that's what the manufacturer does because they want the product to be able to perform at its best under and at load at all times.

So remember the guy the engineered your car and engine makes six figures a year for a reason because he knows things you don't so why try to reengineer your car when you never been to engineering school, if you are trying to extract power and performance you go hard or go home, meaning there is no performance gain in plugs and wires that are worth mentioning, the guys that run quarter mile strips can tell you it starts from the bottom up and costs money lots of money and it aint easy, so don't get ahead of yourself if you build a performance engine then it might call for something different but on an OE engine it runs best and performs best on OE parts even most parts at the parts store have to meet or exceed OE specs. Performance is different and therefore is something to leave to the people that know it best or else you are slapping in parts and hoping for miracles and probably not achieving anything worth talking about, when you build performance engines you are reengineering it for something different than what it was normally built for so that is why you need to know what you are doing or bad things start to happen or it just performs badly.

Just an FYI - on some newer CJDR models Champion is not always the OEM plug. The newer Hemi's have NKG copper plugs as OEM. In general, yes, Chysler has used Champion plugs as the OEM spark plugs. but it is not always the case. Not to pick an arguement, but I have used Autolites (copper) in the 2.5's I've had and they ran just as good as Champions. For me the Autolites were a viable alternative. Your experience may vary.

 

[Bob Lincoln]

And I always get flashover whenever I've used Autolites in any vehicle. And Bosch platinums seem to give a rough idle in these engines. So for the 2.2L and 2.5L, I've found the best performance in the standard Champion RN12YC.

 

[B10alia]

Not to mention the Champs are the cheapest option, most of the time. I know that some of the minivans use platinum tipped plugs with extremely long plug change intervals (thank God, that rear bank is a bear).

"Revolutionary" plugs have been around for ages-- they marketed plugs with RADIOACTIVE TIPS in the late 40's/early 50's IIRC, the theory being the radiation would ionize the air gap and help the plug to fire. If you ask me, the biggest revolutions in plug design have been electrode metals (which really only improves plug life) and the change from screw to snap-on terminals. Look at an OEM spark plug from a Model T and then at one from a 2013 Challenger, and you'll see that they're basically the same. Yes, the newer plug will be a resistor plug, but that was a response to the increase in use of automotive electronics. Stick with what works.

 

[John Wood]

I had to give up on the Autolite platinums when they had a serious manufacturing defect. My car developed a serious misfire a couple of months after changing the plugs so I decided to inspect them. The tips were like new, but the internal center rod in the porcelain had become disconnected and was sparking and burning inside the plug. As soon as I pulled the wires off, it was obvious where my misfire was coming from. On 2 cars that had these plugs installed, a total of 5 were defective. No more Autolites ever. I only use Champions or the OEM recommended plug.

 

[valiant67]

I've had good luck with Autolite plugs years back in Mopars with carbs, haven't bought any in years though. I've had Bosch platinum plugs fail in less than 8k miles in a 1989 Gran Fury and a pair of Neons. Oddly, the parts guy recommended AC Delco Rapid Fire plugs for the Gran Fury to replace the Bosch plugs so I tried them. They were still going 40k miles later without an issue when I sold the car.