PewterMetallic98

I am curious if anyone has used the TR55's that are part number 3951. I grabbed 8 of these for my header install and they were all about $1.70 a piece. They ended up not being copper like the ones I used in the past but I installed them anyway because it was all that I had. Am I using the wrong plugs in my car?

Snake Slayer

I recently did my third plug swap with the 3951. No worries. Did you gap them between .55 and .60 ?

Ikester

excellent plug for LSx N/A cars. Thats all id ever use They are copper core plugs

Barrier

Are these Copper Core? There seems to be 1 yes, 1 no !
Anybody know for sure???
Barrier

PewterMetallic98

Well my Tr55's don't look like they are copper plugs. I have gapped them at 50 in the past in my other cars but this time I left the gap alone. I was told several people have run them without having to regap. Should I pull them all and regap?

Last C5

They seem to be gapped at about 55 out of the box. I'm running them just that way and they seem to be fine.

tstar

The 3951s are copper core plugs and come pre-gapped at .055". The NGK website recommends a gap of .050"...

Double Platinum 7862 PZTR5A-15 0.050
IX iridium 7164 TR55IX 0.050
GP platinum 3403 TR55GP 0.050
V-power 3951 TR55 0.050

I left my gap @ .055" FWIW...

tblu92

YES they are copper plugs--but the key word is "core"they are copper core plugs---meaning the copper is in the center or "core" of the plug

Pwrtrip75

40k miles on a set here, only reason i changed them is i changed headers.