ACDelco Iridium Spark Plugs
05-18-2010, 12:26 AM
#22
TECH Apprentice
I'm guessing what I have is a "round gapping tool." It's a disk that's thin on one part and gradually gets thicker as you go around the disk. How sensitive is this iridium plug? I got NGK TR55IX (stock 7164) that I'm gonna put in with my headers. Is it like, "Oops you touched it, game over!" or what? Can someone show me a pic of the tool you're supposed to use?
05-04-2011, 11:28 AM
#24
11 Second Club
These plugs are PRE-GAPPED and SHOULD NOT BE ADJUSTED. Use a PLASTIC FEELER GAUGE to check gap on these, and be extremely gentle, working UPWARD in sizes until you get close. If you force ANYTHING - even the plastic feeler - tightly against the iridium tip - toss the plug in the trash. You will damage it, if not strip the iridium off the tip altogether. If I can fit a .038 (.965mm) feeler in there comfortably, that's close enough for me. Use your eyeballs, you'll see the gap with the feeler in place - no need to bounce that sucker off the iridium tip to confirm. Stay tight on the ground strap so you avoid the iridium tip. If it's too sloppy, exchange it for another plug. If the plug is NOT gapped properly (ALWAYS CHECK!!!) right out of the box, don't use it.
When I go to get my plugs, whether it be at NAPA for my own car or at the parts dept. for a customer car, I ask them to bring me like 12 plugs instead of just 8, and I check them at the counter to ensure I'm putting a complete, known good set of 8 plugs - with proper gap - in the car.
[edit]
TIP: Try to get plugs from different boxes. When you're installing your plugs, mark the location where the ground strap meets the body. Try to install the plugs in different bores, aiming to have the ground strap mark location pointing towards the bottom of the car. By getting plugs from different boxes, you're hoping to get plugs cut during different manufacturing batches, which means there's a little variation in the threads cut onto the plug. By varying which hole you put the plugs in until you get it lined up pointing down, you're doing a "poor man's plug indexing". If you're within about 20 degrees of pointing downward, you're good. No need to go nuts getting the plugs to ALL point PERFECTLY downward. Just get them close.
Now, this might seem like unnecessary extra work on an engine that's already a pain to change plugs on, but it will provide an extra 1-2% increase in horsepower. Don't think that's much? On even just a 300-hp, engine, that's 3-6 more horsepower, which can make ALL the difference when racing the guy next to you at the drag strip on Friday night. And for the price of gas, I want every bit of power I can get.
Those are the little things that separate the good cars from the great ones. It also brought tons of customers back to the dealer, and they specifically request ME when they come in for service.
[/edit]
-R
Last edited by Bluestreak; 05-04-2011 at 11:45 AM.
05-04-2011, 03:46 PM
#25
Rockstar
iTrader: (15)
Join Date: Feb 2009
Location: I'm on a boat! in Shreveport, La
Posts: 1,582
Likes: 0
Received 0 Likes
on
0 Posts
I had to gap mine, and a couple of the tiny tips broke off. Is this something to be concerned about?
I got a full set for 20 bucks from O reilley's btw.
I got a full set for 20 bucks from O reilley's btw.
05-05-2011, 01:36 AM
#26
11 Second Club
Most people do not know how to properly gap a spark plug, and the center electrodes on the ultra-fine iridium very easily snap if mishandled. There is no warranty for snapped center electrodes. The manufacturers state that an iridium spark plug runs much better than a traditional plug, even if it is not gapped for that motor - they would prefer you just leave it rather than risk snapping the center electrode.
Personally, I gap my iridium plugs for my car, but I am a professional. If you insist on gapping your iridium plug, either have a proper professional show you how or have it done.
-R
05-05-2011, 09:42 AM
#27
Rockstar
iTrader: (15)
Join Date: Feb 2009
Location: I'm on a boat! in Shreveport, La
Posts: 1,582
Likes: 0
Received 0 Likes
on
0 Posts
Yeah, at the time I didn't think they were anything special. I had just told the dude stock plugs for an 09 vette, and he brought out some AC Delco's. I found this thread after the fact. So the tip is their functioning point, how will it run if it's broken off or bent? Is it best to run a full set or is ok to just throw in a cheap plug where the broke tipped ones were?
05-05-2011, 09:53 AM
#28
11 Second Club
I don't know the effect of a broken tip. I've never installed a defective plug. On my own car? I'd probably just replace the ones I knew to have broken tips - if the other plugs made it in there okay, as long as they haven't been in there too long, just leave them. On a customer car sitting in my bay? I'd replace all eight just to be safe.
05-05-2011, 02:24 PM
#31
TECH Fanatic
iTrader: (1)
Join Date: Jan 2009
Location: south jersey
Posts: 1,111
Likes: 0
Received 0 Likes
on
0 Posts
Acdelco iridiums come pregapped at .040 and will run just fine I am. Bolt on only and it runs great. , I got Ngktr5ix plugs. That came gapped at like .030 so my buddy tried to gap them and ruined them and they all started to crack. And back fire. And miss. It was bad. Ended up ruining my injectors. 800 later my car was running good again.
05-06-2011, 03:06 PM
#32
Just get the ngk tr55 iridium ix... they are pre gapped at .058 and you dont have to dick with them. I got mine from rock auto and they were around 60.00... Gm "says" you can run a .040 gap with iridium plugs, but obviously the widest gap you can go without spark blowout will yeild the best fuel mileage and efficiency!! oh and I call bs on anybody paying less than 50.00 for a set of (8) iridium plugs unless you had a coupon or something... ngk ir's run between 50-60.00, ac-delco ir's run around 70.00 and those high dollar junk denso's normally run 80.00+...
05-06-2011, 04:00 PM
#33
11 Second Club
I wouldn't pre-gap plugs more than .045 - remember that as time goes on, plug wear will widen the gap. If the gap is too wide, it removes much of the ignition system's ability to adjust itself as parts wear down with mileage. It also creates high resistance in the secondary circuit even with a healthy ignition system. This requires higher secondary voltages to overcome, which stresses the entire secondary system. It definitely contributes to premature wear of ignition system components.
Plug gap might seem like a small thing you can tweak to your taste, but if your car is more street than strip... gap is more critical, because you're not inside that engine playing with new plugs or re-gapping them all the time. I'm betting most guys with their street cars set the gap wide and forget it for 20k+ miles. I know... those plugs are holy hell to change, so once they're refreshed with new plugs, that's all we wanna hear for a long time. Make the gaps too wide and you'll wonder why coil packs fail, plugs/plug wires have carbon tracks from those super-high voltages trying to escape to ground... it's not good stuff for your engine.
Gap is just another one of those simple little things that contribute to an overall better car. If you're just driving it 1,320' at a time, gap those suckers wide as you feel like and run that car like a rockstar on a rampage.
I just paid $51 at NAPA for a set of (8) 41-110 AC Delco w/my discount this afternoon. They were all gapped at .040, perfectly... no need to adjust at all.
Plug gap might seem like a small thing you can tweak to your taste, but if your car is more street than strip... gap is more critical, because you're not inside that engine playing with new plugs or re-gapping them all the time. I'm betting most guys with their street cars set the gap wide and forget it for 20k+ miles. I know... those plugs are holy hell to change, so once they're refreshed with new plugs, that's all we wanna hear for a long time. Make the gaps too wide and you'll wonder why coil packs fail, plugs/plug wires have carbon tracks from those super-high voltages trying to escape to ground... it's not good stuff for your engine.
Gap is just another one of those simple little things that contribute to an overall better car. If you're just driving it 1,320' at a time, gap those suckers wide as you feel like and run that car like a rockstar on a rampage.
I just paid $51 at NAPA for a set of (8) 41-110 AC Delco w/my discount this afternoon. They were all gapped at .040, perfectly... no need to adjust at all.
05-07-2011, 09:08 AM
#34
I wouldn't pre-gap plugs more than .045 - remember that as time goes on, plug wear will widen the gap. If the gap is too wide, it removes much of the ignition system's ability to adjust itself as parts wear down with mileage. It also creates high resistance in the secondary circuit even with a healthy ignition system. This requires higher secondary voltages to overcome, which stresses the entire secondary system. It definitely contributes to premature wear of ignition system components.
Plug gap might seem like a small thing you can tweak to your taste, but if your car is more street than strip... gap is more critical, because you're not inside that engine playing with new plugs or re-gapping them all the time. I'm betting most guys with their street cars set the gap wide and forget it for 20k+ miles. I know... those plugs are holy hell to change, so once they're refreshed with new plugs, that's all we wanna hear for a long time. Make the gaps too wide and you'll wonder why coil packs fail, plugs/plug wires have carbon tracks from those super-high voltages trying to escape to ground... it's not good stuff for your engine.
Gap is just another one of those simple little things that contribute to an overall better car. If you're just driving it 1,320' at a time, gap those suckers wide as you feel like and run that car like a rockstar on a rampage.
I just paid $51 at NAPA for a set of (8) 41-110 AC Delco w/my discount this afternoon. They were all gapped at .040, perfectly... no need to adjust at all.
Plug gap might seem like a small thing you can tweak to your taste, but if your car is more street than strip... gap is more critical, because you're not inside that engine playing with new plugs or re-gapping them all the time. I'm betting most guys with their street cars set the gap wide and forget it for 20k+ miles. I know... those plugs are holy hell to change, so once they're refreshed with new plugs, that's all we wanna hear for a long time. Make the gaps too wide and you'll wonder why coil packs fail, plugs/plug wires have carbon tracks from those super-high voltages trying to escape to ground... it's not good stuff for your engine.
Gap is just another one of those simple little things that contribute to an overall better car. If you're just driving it 1,320' at a time, gap those suckers wide as you feel like and run that car like a rockstar on a rampage.
I just paid $51 at NAPA for a set of (8) 41-110 AC Delco w/my discount this afternoon. They were all gapped at .040, perfectly... no need to adjust at all.
