rjla67

I picked up a set of NGK TR55-IX Spark Plugs from WS6Store that states that they are gapped for .060. I have a 1998 Z28 and the under hood info label says gap at .060, but I see lots of conflicting info on what they really should be so they are sitting on the workbench for now. Anyone have the answer to what I should gap them or just leave them as is? Any benefits to changing them? I emailed their customer support and got zero help.

flattusmaximus78

iTrader: (1)

Whats done to the car, you can close it if it makes you feel better.

jstrime

I had a 2000 SS that hated any other spark plugs than the AC Delco Platinum from GM. Just my experience. Not trying to sway you different. Hope they work for you.

rjla67

Just basic bolt-ons and a tune. What's the advantage of going down from .060 to .050?

mjs1012

iTrader: (36)

I usually gap those at .55 and have not had any issues.

BoricuaHec01

Leave them as is, already pre-gapped for your qualifications.

demonspeed

iTrader: (7)

Iridiums aren't to be touched; however, GM specs .040 for iridium plugs in LSX motors.

rjla67

Thanks man. I'm gonna gap em at .040 and run them to see how they do. I saw the TSB so I'll follow their recommendations.

BWZ_2k2Z28

I was told the same thing by a mechanic. He said that iridium should come gapped to your specific application and not to do anything to them other then to measure the gap to make sure they are correct. I seen the general consensus around here is running .45-.55 so that's what I wanted to run. But I couldn't find any iridium plugs with a gap different then then .59 and I wanted iridium so I couldn't do it once and not worry about it again.

So what are your options with iridium plugs? Can you change the gap in them or not?

rjla67

I ended up getting a new set. The ones I originally got was the NGK TR55IX #7164 that comes pre-gapped at .060. I checked the NGK website and the what they recommend for my Camaro is #7397 which are gapped at .040.

I also called WS6 and talked their tech finally who also recommended .040 and I just need to re-gap the ones I originally bought. I said screw that and got the correct ones and these will be shipped back for the tip on the iridiums are so thin it wouldn't take much to break them.

The new ones will be going in tomorrow so hope all goes well.

rjla67

Also wanted to add demonspeed brought up the TSB with the new iridium plugs and GM now says .040 for gap contrary to the engine label that says .060.

BWZ_2k2Z28

well this thread has sold me. I'm runnin the iridiums with a .06 gap and I swear I can hear spark knock when under load. I've had 3 different people in the car with me and I'm the only one that can hear it. I'm getting SH*TTY gas mileage too. As soon as I get a warm day I'm swapping plugs.

rjla67

This was added to the WS6 website after I spoke to them today:

"Prior to 2005 GM used .055 GAP spark plugs on all LSx motors (this size). Starting in 2005, they switched to .040 GAP plugs to provide a better idle when things like cheap gas are encountered. Either a .060, or .040 GAP plug will work in any LSX motor with the smaller GAP being best for daily driven, mildly modded cars."

(http://www.ws6project.com/user_stor/...s-box-of-4--1/)

BTW, the local AutoZone/Advanced Auto carries the NGK #7397 FWIW.

demonspeed

iTrader: (7)

Kudos to rjla67 for providing some good specifics regarding the platinum vs. iridium transition

Just as an aside, GM replacement plug is ACDelco 41-110. These are the ones I went with when I did long tubes. I did not even check the gap before installing because I did not want to stress over screwing up the tip

BWZ_2k2Z28

HAHA exact same here. $6 a plug? There was no way I was gonna even risk it.

rjla67

Got them installed this morning. After a brief hiccup with the #6 cylinder not firing for the plug wire wasn't fully seated, the engine purrs like a kitten.

The plugs I took out were from the previous owner and still the original plugs. They were AC Delco (#41-931) and were gapped at .060 (some even wider then that).

So in summary if anyone is looking to put some iridiums make sure they are gapped at .040 with the part numbers in the above post and you will be fine.

Thanks everyone for their contribution.