Because of the slight difficulty in changing spark plugs on the 2.8 V6 (front side), I've considered using irridium spark plugs, due to their long lasting durability. I had used them on my previous Fiero without any issues. What is everyone else's opinion/experience with irridium spark plugs? Thanks for all who offer input.
Many members 'swear' that the Original Equipment R42TS Copper plugs are the best on the V6, but like you - I 'hate' changing the right bank plugs so often......
I changed to ACDelco Platinum "Rapidfire" Spark Plugs many moons ago for the same reason and never looked back!
*EDIT* After reading comments below, I hope PFF members know that the factory 30k-volt ignition coil is the 'weak link'....... And of course, everybody has different priorities on a spark plug.........Performance, Maintenance and Cost. Mine: Normal Street Use and Low Maintenance / 50k-Volt Coil and Platinum Plugs @ .045 Gap
------------------ Original Owner of a Silver '88 GT Under 'Production Refurbishment' @ 136k Miles
[This message has been edited by Vintage-Nut (edited 02-20-2024).]
Copper are technically better, and using other types can lead to some weird behavior in some cases, behavior that is hard to troubleshoot, as many ignition issues are, can cause slightly less power and fuel efficiency, perhaps replace your dogbone bushings, that will pull the engine back up to another 1/2 inch, which can definitely help with access. Another thing to think about is that you might want to change them more regularly, as the front bank has the tenancy to rust in, which is much more of a pain to get out then 2 or 3 normal changes, with no rust, it is honestly equivalent to changing the oil filter, which has to be done very frequently. Just get in the trunk, lay on the intake, and find the right combination of extensions to get them out.
I installed the ACDelco RapidFire plugs in my 3.4 F-body converted V6....One thing that made the front three much easier to change; jacked car up, then removed the dog-bone and the two rear subframe bolts and using my jack lowered the engine/trany/subframe a few inches which tilted the engine back...
Just make sure you reinstall the bolts and dog-bone (had to chase my dog around the yard to get it back from her)
Also, I used compressed air to blow out debris from around the plugs, then sprayed some penetrating oil around the base of the plugs and let it sit for a day- then started the engine and let it run for a few minutes (Applying some heat)...then, after cool-down, sprayed some more...a couple of days later, the plugs came out easy.
[This message has been edited by cvxjet (edited 02-19-2024).]
Opinions about spark plugs, especially in Fieros, vary about as widely as opinions on where you can get the best cheeseburger. At any rate, here's my experience regarding spark plugs and my one essentially stock 1988 Fiero GT.
I use NGK Iridium IX in all my cars for the past decade or more - except my Fiero).
Several years ago I put IRIDIUM plugs in the Fiero and it seemed not to like them much. So I put stock Champions in it and did a lot of troubleshooting of the ignition system and finally got it to run really well. By the way, NONE of the problems were the plugs, but then, I already had the garden variety Champion Copper Plus plugs in it when I got it sorted out, so I left them.
BUT...
In my experience, most 'standard' spark plugs degrade fairly quickly compared to the more exotic ones. My rule-of-thumb over the last 50 years or so has been that they should be replaced every 15-20,000 miles, regardless of engine or make or ignition system. I did feel like the ones in my Fiero were showing some age and wear before 20k. I was a little hesitant about going back to iridium, because my ignition system is completely stock (unless you want to make an exception for my 'star-wheel' type distributor) - stock coil, stock ICM, spiral-wire core plug wires. I read a white paper (got it here somewhere).where I read that iridium and some other electrode materials were harder to fire than metals like nickel or platinum (most all plugs have copper cores). In the end, I went with NGK G-Power Platinum plugs. They don't have the expected life of iridium, but way longer than standard plugs. They're running great, after two years and about 7000 miles. They say platinum plugs will last " up to 100,000 miles"; I'll be looking to replace these at maybe half that.
None of this is to say that iridium plugs won't run well in a stock Fiero; just my experience, and I haven't tried iridium plugs in my Fiero since that troubleshooting stage. But I sure like these platinum ones right now.
I have no opinions on this... but I'm curious to learn more about why certain plugs are recommended for certain engines.
Anyone know a good website that explains the heat rating, depth, etc... of the spark plug? And finally... the difference between the metals and why it matters? I know that some metals are more conductive, but that some of them also corrode faster (like Copper or steel). Some require a hotter voltage to produce the same spark for a more conductive metal with a lower spark, but don't last as long.
I have no opinions on this... but I'm curious to learn more about why certain plugs are recommended for certain engines.
Anyone know a good website that explains the heat rating, depth, etc... of the spark plug? And finally... the difference between the metals and why it matters? I know that some metals are more conductive, but that some of them also corrode faster (like Copper or steel). Some require a hotter voltage to produce the same spark for a more conductive metal with a lower spark, but don't last as long.
I think it is mainly the conductivity, the factory v6 ignition system is underpowered to say the least, they use the same coil as the 4 cyl, to run 50% more cylinders, which means it is underpowered, especially at higher rpms. With stock .045 gap, copper plugs will have the best conductivity, and the hottest best spark, other plugs may not have a good disk with the stock coil, but with a better coil, that will make up for the lower conductivity, and give you normal spark with the long life. If you upgrade the coil, and keep the copper plugs, and increase the gap so you have a normal spark intensity, but it is bigger due to the better coil, you can get actual power gains.
Bottom line, more power=some combo of copper plugs, better coil, bigger gap. More life with original power=other plugs, better coil, original gap. What most people do=other plugs, weak coil, same gap=less power, less fuel economy, etc.
All of this is dependant on rpm to, if you never go above 4000, you might not notice any difference in plugs, or gaps, or whatnot, but apparently power drops off majorly around 5000rpm because of the load on the coil.
[This message has been edited by 1985 Fiero GT (edited 02-19-2024).]
I have no opinions on this... but I'm curious to learn more about why certain plugs are recommended for certain engines.
Anyone know a good website that explains the heat rating, depth, etc... of the spark plug? And finally... the difference between the metals and why it matters? I know that some metals are more conductive, but that some of them also corrode faster (like Copper or steel). Some require a hotter voltage to produce the same spark for a more conductive metal with a lower spark, but don't last as long.
Is there a good chart for this?
Plugs for Forced Induction are important because of the heat range. You typically go with a colder plug because of the compressed air being forced into the cylinder. Beyond that I just look at a spark plug as a spark plug, don't get lost on the snake oil of the "fancy" plugs.
In doing some more research on this, I found an interesting article. It compares the pros and cons of irridium to platinum. https://rxmechanic.com/iridium-vs-platinum/ The main thing I took from this article is that all plugs have a copper-core element. It is just the tips that are made of different materials. Irridium costs double that of platinum. The higher cost of the irridium plug was the only 'con'. The main benefit is that the irridium tip lasts twice as long as the platinum tip. Hope this info helps others.
Originally posted by 1985 Fiero GT: All of this is dependant on rpm to, if you never go above 4000, you might not notice any difference in plugs, or gaps, or whatnot, but apparently power drops off majorly around 5000rpm because of the load on the coil.
I can absolutely attest to this. Back over 15+ years ago when I used to drive my 87 SE/V6 regularly... it performed just as you said until I upgraded my ignition coil. I went with an Accel SuperCoil (or whatever it was called back then). Bright-yellow coil which I spray painted black to look stock. I noticed idle was slightly improved, but that could have just been plecebo. I didn't notice any power increase until around 4,500+ rpms. Essentially, the difference was that the engine continued to pull strong as it did in the mid-range, and it felt like I had more actually usable power in the upper RPMs than I did before. It clearly made a difference.
I've had a lot of people tell me this isn't so... maybe my stock coil was starting to go... but either way, your point about the 4cyl coil and the V6 coil is on point. The coil is basically a capacitor of sorts... and it simply cannot maintain / recharge quickly enough to provide that level of voltage to the spark plugs at the higher RPMs. There have actually been dyno tests that have shown this. I saved them somewhere, so maybe I'll make a page about it one day.
For both my daughter's car, and my car, we plan to use the MSD 6EFI system. In addition to the multiple spark discharge feature, it also provides a more complete burn to help eliminate carbon deposits from ever occurring... or at least not as frequently, and is supposed to smooth out idle. On her little 4 cyl, I doubt she'll ever see a power increase from it, but anything we can do to improve the efficiency of the motor will be useful. For me, it's about the learning opportunity with her. We'll rebuild and put everything back to stock, and then install that in an inconspicuous place along with the factory wiring to see if there's a change in idle and normal around-town driving.
While we're in the category of spark plugs, what are your thoughts/experience with using anti-seize on spark plug threads?
Me and my dad always do, I haven't been into cars long enough to have to take out old spark plugs with anti seize, but it's a good precautionary thing to do.
Originally posted by 82-T/A [At Work]: I can absolutely attest to this. Back over 15+ years ago when I used to drive my 87 SE/V6 regularly... it performed just as you said until I upgraded my ignition coil. I went with an Accel SuperCoil (or whatever it was called back then). Bright-yellow coil which I spray painted black to look stock. I noticed idle was slightly improved, but that could have just been plecebo. I didn't notice any power increase until around 4,500+ rpms. Essentially, the difference was that the engine continued to pull strong as it did in the mid-range, and it felt like I had more actually usable power in the upper RPMs than I did before. It clearly made a difference.
I've had a lot of people tell me this isn't so... maybe my stock coil was starting to go... but either way, your point about the 4cyl coil and the V6 coil is on point. The coil is basically a capacitor of sorts... and it simply cannot maintain / recharge quickly enough to provide that level of voltage to the spark plugs at the higher RPMs. There have actually been dyno tests that have shown this. I saved them somewhere, so maybe I'll make a page about it one day.
For both my daughter's car, and my car, we plan to use the MSD 6EFI system. In addition to the multiple spark discharge feature, it also provides a more complete burn to help eliminate carbon deposits from ever occurring... or at least not as frequently, and is supposed to smooth out idle. On her little 4 cyl, I doubt she'll ever see a power increase from it, but anything we can do to improve the efficiency of the motor will be useful. For me, it's about the learning opportunity with her. We'll rebuild and put everything back to stock, and then install that in an inconspicuous place along with the factory wiring to see if there's a change in idle and normal around-town driving.
My car's off the road for the winter, I'm working on it, and I replaced the ignition coil with the MSD stock size/location one, 50% higher volts, and red. I also got top of the line red spark plug wires, and regapped my plugs to .060 (4 cyl stock gap) to take advantage of the higher volts. As I haven't been able to drive it. I can't say anything about performance yet, but idle is smoother, and throttle response is better. That combined with ported exhaust manifolds, Rodney EGR tube, cleaned out PCV valve, and some other things have made my idle rock solid, much improved sound and throttle response. And should improve power and fuel economy.
I had a gm piece of .... that every 40k would fracture the ceramic insulator on #1 cylinder. The TSB was a waste of time and even installing the high end plugs didn't fix my problem. Ignition is all about providing a source to ignite the fuel/air mixture. If you're building a performance motor go for it. I remember the v6 being a pain on the plugs if you're looking for a long lasting plug I think you're wasting $ on iridium or even the newer ruthenium.
I'm surprised GM didn't design some kind of dew strip to prevent water from going down the backside of the glass and onto the spark plug holes.
Oooh... that's right.
If I remember right they did, but even then it wasn't enough. It didn't stay sealed when the trunk was opened, which pours a ton of water down there, that is mainly what cracks that manifold and puts enough water in the plug holes to rust them out. I saw a design awhile back that was a sort of tarp, that connected between the trunk and the firewall, and funneled the water out the sides, onto the air box and battery, that's better for the hot engine.
⚠️ No matter what plugs are installed, you need to check, clean or even replace them or have corrosion eats the "body" metal.
Example: i use AC or Autolite "Double Platinum" (because duke dis engine) that have coating to prevent rust but #1 plug still gets rust because close to right vent that allows "water" to getting to it. Results: see https://www.fiero.nl/forum/...HTML/146263.html#p10
V6 & many Swaps have similar or worse problems when have "fire recall" done that removes the lid strip controlling rain & crap getting thru the window gap w/ the deck lid.
Any buildup will cause problems like look at #3 & 4 in link when "dirt" have remove the coating just above the cone & those plugs are "protected" by the air cleaner. @ minimum check/clean the plug base even w/o removing them & remove rust/dirt around the plugs w/ small picks & compress/canned air.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
If Fieros were common as Camrys, I think I'd open a business changing V6 spark plugs. A lot of people seem to loathe that job. They are mildly difficult to get to, but not that big a deal once you find the right combination of extensions and a U-joint. Sometimes you also need to vacuum rocks and leaves first.
I've always used copper. Originally that's because I had to take a CA emissions test every 2 years. It made sense to schedule the plugs as part of my pre-test ritual. Copper is good for a short interval. I don't have to take tests anymore but I still use copper. I don't want to risk them seizing into the head, so I won't extend the replacement interval long enough for anything beyond copper to be useful.
If Fieros were common as Camrys, I think I'd open a business changing V6 spark plugs. A lot of people seem to loathe that job. They are mildly difficult to get to, but not that big a deal once you find the right combination of extensions and a U-joint. Sometimes you also need to vacuum rocks and leaves first.
I've always used copper. Originally that's because I had to take a CA emissions test every 2 years. It made sense to schedule the plugs as part of my pre-test ritual. Copper is good for a short interval. I don't have to take tests anymore but I still use copper. I don't want to risk them seizing into the head, so I won't extend the replacement interval long enough for anything beyond copper to be useful.
Agreed! Spark plus are much easier then some things
AC Delco stock copper plugs. Front bank is easy to change if you go from the end of the block, not over the top. 3/8" ratchet and a plug socket is all that's needed.
It is absolutely imperative to make sure the spark plug well on the head is free of debris before putting a socket on the plugs.
Since you're working by feel, it helps to close your eyes.....🙂
⚠️ Also a problem is most install the plugs way too tight making remove them next time very hard.
Cone plugs are very tight often < 1/8 Turn of a wrench after tighten by fingers until cone hits. Other engines w/ Gasket plugs need ~ 1/4 Turn the First Time to crush the gasket but if reused latter the gasket plugs "act like" cone plugs & doesn't need same 1/4 turn.
Is why many lawn mowers to car engines w/ Al Heads & plug holes stripped because previous work over torque the plugs. In Iron heads have same + rust damage but often = plug's base metal breaks or strips.
Side Note: Is why many Plug Wrenches w/ universal joints etc are "weak" even from known good tool brands... They don't expect a lot of torque.
[This message has been edited by theogre (edited 02-25-2024).]
I don't have to take tests anymore but I still use copper. I don't want to risk them seizing into the head, so I won't extend the replacement interval long enough for anything beyond copper to be useful.
I like to live life on the edge. I last changed the copper core plugs in my Formula, which is parked outside in the rain... nine years ago!
[This message has been edited by Patrick (edited 02-25-2024).]
I always apply anti-seize to sparkplug threads, and dielectric grease to the inside of the sparkplug cable boots (at both ends).
Yes, Patrick. I took your advice years ago. I have always used dielectric grease on electrical connections like spark plug wires. I just installed the iridium plugs using anti-seize and dielectric grease.
