Replace spark plugs every 4 years

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Originally Posted by Kira
Closely related situation:
As many of you have read here.......

I bought a 15 year old Ford Ranger with I was thinking of changing the plugs and wires. All the parts guys I ask say, "leave 'em be".
NOTE: The wires are Ford, grey originals with smooth silicone based jackets, not dry at all.

One guy on a Ranger forum suggested having a Ford dealer do it. I imagine he believes any chance of complication would be lowered and, perhaps, any which could arise would be remedied for no additional cost.

1) What would you do? please, just rattle off opinions
2) Does anyone know if copper based or nickel based anti-seize would perform better?

So far I've been periodically dripping Kroil (a penetrant) on the plugs' bases.

I hope this post doesn't constitute a thread highjack.


Ford tends to be picky about the plugs, I'd just get the motorcraft ones and change them. Not sure if it was used on your car, but they also used a waste fire system so they fired twice per cycle, once also on the exhaust cycle. I remember changing the plugs on my Taurus at 80k and the plugs were worn even though they were supposed to be 100k plugs. They weren't completely worn out but it wasn't like they looked like they were brand new and mileage did increase a little bit afterwards as the gap had opened up. Misfires are usually from plugs, wires and coil packs. And it doesn't take long for a misfire to burn out your cats.
 
The TGDI Hyundai/Kia engines (Theta II and Gamma) seem to all call for changing iridium plugs every 45k mi.
Seems these little turbo engines are hard on plugs.
Cost of making over 100hp per liter.
 
Originally Posted by Snagglefoot
I haven't seen the word Iridium in this thread. ( or did I miss it?)

For Iridiums: 100,000 miles.
smile.gif



Iridium is old tech. Its all about ruthenium these days
 
I have NGK 97506 Iridium in N63TU Bmw V8 twinturbo, they do not last 100.000miles, not even close. More like 30.000 miles with the right gap. Direct injection engines require a lot of spark plug.
My old Volvo 740 turbo with B230 engine had the same spark plugs for 120,000 miles without a misfire.
 
Correct gap?

I haven't gapped a spark plug since the 80's. The new iridium and ruthenium plugs are preset at the factory. You might mess things up by gapping them yourself.
 
Quote
...Iridium is old tech......
Perhaps, idk. However, I'm very satisfied with 100k mile performance I got out of OE Iridium in a Honda posted here. In fact, liked them so much I went right back to Iridium plugs. I guess I like me some old tech.

As for topic, personally I'd stick with the OE recommended plug following the recommended service interval.
 
Originally Posted by LotI
Originally Posted by vw7674
probably four years due to aluminum cylinder head & steel threaded plug.
Dissimilar metals means it's safer to extract the plug earlier rather than drama / damage to threads in the head later.

This.

At least crack them loose to make sure they can come out. Do NOT use anti-seize as it affects conductivity.

I'm a bit dubious about this, since plug wires are usually measured in many k's of ohms per foot. A few ohms at the plug isn't a problem.

Or are you talking about thermal resistance? Hmm, that could be something else.
 
I almost never buy sparkplugs. The few times I bought sparkplugs, wow, no difference at all. I just regap them when I take them out, which is almost never, and most of the time they are ok. People will argue that the metal electrodes if they are not crisp and flat dont work, I see no difference in idle or mpg with old plugs. I have some plugs have gone over 100,000 miles.

As long as a plug is not fouled, it is going to fire with the very high voltage of today.

This is only for American cars, maybe Europeans ones need new plugs frequently. My dad had a Mercedes and a trunk full of old plugs, which looked good to me. IMO, he wasted a lot of money and time buying new plugs.
 
Originally Posted by sdowney717
I almost never buy sparkplugs. The few times I bought sparkplugs, wow, no difference at all. I just regap them when I take them out, which is almost never, and most of the time they are ok. People will argue that the metal electrodes if they are not crisp and flat dont work, I see no difference in idle or mpg with old plugs. I have some plugs have gone over 100,000 miles.

As long as a plug is not fouled, it is going to fire with the very high voltage of today.

This is only for American cars, maybe Europeans ones need new plugs frequently. My dad had a Mercedes and a trunk full of old plugs, which looked good to me.

That's the point of changing plugs, change before problems occur. If you wait, you can run into misfire, which can be hard on the catalytic convertor, and which may lead to low mpg also.

I've heard that high voltage can be hard on the ignition components also. Yes they are meant to used at high voltages, but in service, the ignition only develops high voltage as required--once the voltage rises up to what is needed to arc, the voltage collapses as the current flows. But as the plug gets older, voltage rises, and this can stress the insulation elsewhere.
 
Originally Posted by supton
Originally Posted by sdowney717
I almost never buy sparkplugs. The few times I bought sparkplugs, wow, no difference at all. I just regap them when I take them out, which is almost never, and most of the time they are ok. People will argue that the metal electrodes if they are not crisp and flat dont work, I see no difference in idle or mpg with old plugs. I have some plugs have gone over 100,000 miles.

As long as a plug is not fouled, it is going to fire with the very high voltage of today.

This is only for American cars, maybe Europeans ones need new plugs frequently. My dad had a Mercedes and a trunk full of old plugs, which looked good to me.

That's the point of changing plugs, change before problems occur. If you wait, you can run into misfire, which can be hard on the catalytic convertor, and which may lead to low mpg also.

I've heard that high voltage can be hard on the ignition components also. Yes they are meant to used at high voltages, but in service, the ignition only develops high voltage as required--once the voltage rises up to what is needed to arc, the voltage collapses as the current flows. But as the plug gets older, voltage rises, and this can stress the insulation elsewhere.

If you believe your plugs are too old, then you should change them, keeps businesses income flowing.
 
Originally Posted by sdowney717
Originally Posted by supton
Originally Posted by sdowney717
I almost never buy sparkplugs. The few times I bought sparkplugs, wow, no difference at all. I just regap them when I take them out, which is almost never, and most of the time they are ok. People will argue that the metal electrodes if they are not crisp and flat dont work, I see no difference in idle or mpg with old plugs. I have some plugs have gone over 100,000 miles.

As long as a plug is not fouled, it is going to fire with the very high voltage of today.

This is only for American cars, maybe Europeans ones need new plugs frequently. My dad had a Mercedes and a trunk full of old plugs, which looked good to me.

That's the point of changing plugs, change before problems occur. If you wait, you can run into misfire, which can be hard on the catalytic convertor, and which may lead to low mpg also.

I've heard that high voltage can be hard on the ignition components also. Yes they are meant to used at high voltages, but in service, the ignition only develops high voltage as required--once the voltage rises up to what is needed to arc, the voltage collapses as the current flows. But as the plug gets older, voltage rises, and this can stress the insulation elsewhere.

If you believe your plugs are too old, then you should change them, keeps businesses income flowing.

I don't understand--I replaced a set at 80k and they did look a bit worn; turns out they were supposed to be replaced at 30k. The other two were changed as per schedule at 120k. I'll probably replace one of those vehicles before it needs another set; the other will likely have them replaced at 240k as per schedule.

Not sure how this keeps business income flowing...?
21.gif
Would rather change plugs than a cat.
 
I got a 1996 Trooper with 207,000 miles and the plugs have over 100,000 miles on them. MPG had started drooping years ago and it got too low at 13.5mpg.
I thought well maybe the plugs are bad, but no, did not change them as it runs very smoothly.
What went bad was the O2 sensors in front of the cats due to they were old and original.
NO CODES, but old O2 sensors get lazy, and they enrich the mixture too much.
I replaced them with new ones, and gained 4 to 5 mpg.
Exhaust smells cleaner too.

I dont care if some people dont believe this.
 
Originally Posted by sdowney717
I got a 1996 Trooper with 207,000 miles and the plugs have over 100,000 miles on them. MPG had started drooping years ago and it got too low at 13.5mpg.
I thought well maybe the plugs are bad, but no, did not change them as it runs very smoothly.
What went bad was the O2 sensors in front of the cats due to they were old and original.
NO CODES, but old O2 sensors get lazy, and they enrich the mixture too much.
I replaced them with new ones, and gained 4 to 5 mpg.
Exhaust smells cleaner too.

I don't care if some people don't believe this.


I absolutely believe it. I like your car - almost bought one with a stick a 2 decades ago.

Nice V6 engine.

-Ken
 
Originally Posted by supton
...

I've heard that high voltage can be hard on the ignition components also. Yes they are meant to used at high voltages, but in service, the ignition only develops high voltage as required--once the voltage rises up to what is needed to arc, the voltage collapses as the current flows. But as the plug gets older, voltage rises, and this can stress the insulation elsewhere.


You are 100% correct. On today's engines, the coil pack will increase its duty cycles to offset the worn plugs. For the most part, we will never experience a miss due to worn plugs. The coils just work harder. Result is the coils die a premature death that could have been prevented by changing our plugs based on mileage run.

I sent you a PM.
 
Eh... no. I change mine every 2 years regardless if they've hit their miles or not. The one time I let a set of OEM plugs run to the "recommended" 100,000 miles, it was a major pain in the arse to get them out. Ended up having 2 break in the hole. Never again. Anti-seize and change every 2 years, no matter what. The track car being the exception as it gets new plugs at the beginning of each season. Plugs are cheap.
 
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