Reality check on platinum plugs


#1

Hopefully a simple question. My mechanic recommends against using platinum plugs in my 1997 Civic LX since it originally came with regular copper ones. I can’t see how it would make any difference as long as they’re the right heat range and length. In addition, I’ve always had good luck with NGK platinums. Who’s right here?


#2

Your going to get a lot of people that will tell you they are a waste and go with (fill in the blank). Somebody will probably suggest something rediculous. I say go with what you prefer. If you prefer NGK platinums then so be it. I have an old Nissan 4x4 I use those in and it runs better and gets better mileage than the regular copper ones. Now maybe thats a placebo and I’m just imagining it runs better, but I’m willing to spend the few extra bucks for the illusion and better mileage. Personally I’ve found my Nissan and Toyota run best on NGK platinums, my VW runs best on Bosch platinums and my Pontiac runs best on AC Delco platinums. So go with what floats your boat.


#3

In theory, you should not be able to tell any difference for the first 10,000 miles or so. The reason platinum plugs exist is so the engine will hold its emission levels for the 50,000 mile requirement that manufacturers must meet with new engines.

In practice, I pulled NGK platinums out of two of my BMWs and put in Bosch standard plugs. I immediately noticed that I have to crank the engine a split second longer before the car starts. It is no longer just “touch the key and it is running”. As for the performance and mileage, I don’t track that as closely as I should, so I can’t tell you if there is any difference.

The NGKs looked perfect after 50,000 miles. I should have put them back in instead of throwing them away.


#4

Believe it or not, copper is a better conductor than platinum. Most cars will perform better with copper plugs. However the downside of the copper plug is that they wear out much faster than a platinum plug will. This can be a real pain if you have a car with a transversely mounted V6 or V8 where the rear plugs are tough to get to. Anyone who has changed plugs on a Windstar can attest to this. Copper plugs usually last about 50%-60% as long as platinums do. Because of this it’s usually worth it to use platinums for their longevity alone.


#5

Since platinum plugs last longer than regular plugs, they’re usually installed on engines where access to some of the plugs is difficult. But if the plugs are easily accessed, I go with the regular plugs.

Tester


#6

NGK platinums will work just fine and they will last much longer than coppers. Your mechanic is in the habit (a good one) of always telling customers to stick with OEM stuff. I presume many customers will ask him to install wacky non-standard substitutes and he has to constantly discourage them. In this simple instance, you can readily upgrade to those platinums.


#7

You will NOT GET BETTER PERFORMANCE OR BETTER GAS MILEAGE by using Platinum plugs…IT’S IMPOSSIBLE.

What platinum plugs offer you is they last a LOT LONGER then standard plugs…PERIOD.

NGK are the OEM plug for Honda and Nissan. I LOVE NGK plugs. They make a excellent quality plug. Stick with NGK plugs and you’ll be happy. Copper or Platinum are fine, but the Platinum is NOT needed.


#8

As the other posters have mentioned, the only advantage of a platinum plug is that they last a lot longer. In my mind, though, I’m not really comfortable leaving a plug in my engine for much longer than the change interval on a copper plug, since they can get fused to the engine and can become very difficult to remove. If they’re installed with proper torque and anti-sieze, it shouldn’t be a problem, but it’s probably a good idea to pull the plugs out anyways at the OE-recommended interval to check 'em, and since copper plugs are so cheap, I figure might as well replace them.


#9

Believe it or not, copper is a better conductor than platinum. Most cars will perform better with copper plugs. However the downside of the copper plug is that they wear out much faster than a platinum plug will. This can be a real pain if you have a car with a transversely mounted V6 or V8 where the rear plugs are tough to get to. Anyone who has changed plugs on a Windstar can attest to this. Copper plugs usually last about 50%-60% as long as platinums do. Because of this it’s usually worth it to use platinums for their longevity alone

Platinum and their sisters Iridium Plugs are all Copper cores. Only the tips are Precious Metal.

Like Mikein NH said, the only reason to use Precious Metal plugs are for an extended change interval.

Use Double Platinum or Iridium when changing plugs in a “Waste Spark” ignition system. (One coil fires two plugs at the same time.) If you use single Platinum Plugs on this system, one plug will wear out faster than the other. (The spark arks from center to side on one plug and from side to center on the other.) If you use Single Platinum, you have to change them as often as the Copper cores.


#10

What about the Denso Iridium plugs on the box it is advertise a increase on accelartion + Longevity + Fuel consumpution is that so or is another Scam so we can waste $8 buck more on each plug comparing them to regular plugs ?


#11

Gee and there’s this advertisement about water for gas too.

Iridium is a very very durable substance. It will make the plugs last a LOT longer.

The ONLY way it can increase acceleration is if the plugs you’re replacing are very worn/old. They will NOT increase acceleration or decrease fuel consumption more then just regular plugs will.


#12

Some “waste spark” ignition cars have double plats in some positions and single plats in others for that reason and the fact that it saves the manufacturer a few cents to use the singles in some positions.

I doubt that the increased resistance of the platinum or iridium electrodes has much effect with today’s high power ignition systems.

Cripes, a platinum plug is going to cost a dollar more than copper. Even with an 8 cyl engine that is only 8 bucks. For what you pay to have them installed, you might just as well have a long-lasting plug.


#13

" Some “waste spark” ignition cars have double plats in some positions and single plats in others for that reason and the fact that it saves the manufacturer a few cents to use the singles in some positions. "

WHAT???!!!


#14

Believe it or not, copper is a better conductor than platinum.

Compared to the resistance of carbon core spark plug wires, the small extra resistance of platinum is lost in the background. Some spark plugs have resistance put in them on purpose to suppress radio frequency interference. The amps that go through the spark plug is so low that the resistance is inconsequential.


#15

" Some “waste spark” ignition cars have double plats in some positions and single plats in others for that reason and the fact that it saves the manufacturer a few cents to use the singles in some positions. "

WHAT???!!!

True True True. Ford did that. Sneaky Bean counters.

I just changed the plugs on my Hemi Charger. That’s sixteen Autolite Iridiums to replace the Copper Core Champions installed at the factory. Two plugs per cylinder with one coil pack firing both plugs mounted on the valve cover. No more 30000 change intervals for me!!!


#16

Oh, the irids cost you quite a bit more. I might have stuck with double plats with 16 plugs. The fact is, that the double/single thing worked pretty well in the early 90s Fords. The plugs wear at the same rate. The interesting thing is that I think that they specified doubles for replacement. They must have figured out that the people replacing them would fudge and use cheaper plugs in all positions not understanding the issues, or could not keep them straight.


#17

“Waste spark ignition” means that EVERY plug fires twice per combustion stroke. Once to fire the fuel / air mix and one “wasted” spark 360 crankshaft degrees later, at the end of the exhaust stroke.

So, based on this information, which “position” gets single platinum and which gets double platinum?


#18

I agree with greasyjack about not leaving spark plugs in for extended periods. Other than the minor, and quite possibly unnoticed misfires, repairing threads can be a real pain in the neck depending on the vehicle and engine application.

A few weeks ago I replaced the original plugs in my son’s Lincoln Aviator (aluminum heads, 45k miles on it) and I was sweating bullets on all eight of those plugs. It was a wrestling match and took penetrant and a lot of back and forth motion to get them out without destroying the threads.

Other than that I agree with the others that there’s no difference except longevity; at least most of the time.


#19

You have to agree though that by the time most people change their spark plugs, it would be kinda true. I’m actually surprised there hasn’t been any “My 2nd car, 10 years old, only has 15k miles on it, but my mechanic says I should replace them. I thought that plugs were good for 60 to 100k miles” type of posts.


#20

“Oh, the irids cost you quite a bit more. I might have stuck with double plats with 16 plugs.”

The place I got them did not have enough Double Platinums stocked for the car. The price was reasonable for the Iridiums and they had 16 on the shelf at the time.

“So, based on this information, which “position” gets single platinum and which gets double platinum?”

The plugs that has the Spark arc from the Center Electrode to the side get the single Platinums. The plugs that arc from side to center get the Double. Single Platinum plugs have no Platinum on the side electrodes.