I just found out from my trip to Summit that the ONLY NGK plugs recommended for our LT1's are the OEM replacement Laser Cut Double Platinum. All other NGK's have had issues with our engines and are NOT recommended.

Summit sold me NGK TR55 GP's under listing in a older dated catalog. The new NGK catalog shows only one plug for our cars. The OEM laser cut double platinum, also found as the only plug for our car on their site.

All of their other plugs may work in our cars but have had know issues, hence the updated catalogs which only recommend one type of plug. TR55's / TR55 GP's / and the Iridium ones are no longer recommended. I was told that was the reason I have had consistant problems with my GP's. NGK has stated that other plugs may work but are not recommended and you may experience issues, similiar to my missfire.

Just thought I'd let everyone know. And BTW the NGK OEM replacements are $12 each. Looks like AC Delco for me.

-Dustin-

 

I always ran delco plugs in my car before the supercharger. Now I use the NGK TR6 and I've had no problems with them.

 

I've had TR6's since the beginning.

are you saying they are discontinued or that they are "not recommended?"

 

Yes, I was told they can work but sometimes do not. If they work, great, but if not, like in my case, now you know why. I will be contacting the NGK tech Monday to verify everything, he left early today.

-Dustin-

 

Pretty good chance this: is why they want you to buy them.

TR55s have been used in my old '96 for over 30k miles (odo is over 100k now) and in my '02 for over 20k miles...without any problems. Most people I know with LT1/LS1s are running either TR55s or TR6s and they've never had a problem either.

I don't see any reason to stop using them and at less than $2 a piece, a plug change doesn't cost me $90+.

 

Napa,about $1.79 each reg. plug.(NGK))
Whats another word for horse manuer.Thanks,but no thanks Summit.(
Aren't they just a distributor of auto parts,Like autozone?) No flames ment,but come on,might do a search up above and see what folks like here.My02

 

I am just saying that there must be a reason that NGK told me that they no longer recommend their other plugs. I am just trying to pass on some knowledge so what happened to me doesnt happen to you guys. Dont beleive me call the NGK tech guy yourself.

-Dustin-

 

Sorry,I don't know what the GP plug is.All I know is I"m ok with the tr55.Works for me,delco's work for me for about 3000 miles,then don't deliver the same power as when they were new.(tried this twice).Pulled the delco's after 3000.,and 4 of them had no plat. pucs on them.They went where?(car always starts with 1/2 half turn on the ignition with NGK's.)Hope this helps.

 

Well these GP's are killing me, and I am stuck in a position where I need to get new plugs. I dont like the fact that the AC Delco's lose the pucks, so I am kinda clueless at this point. I am doing all my installs tomorrow, so I am not sure what the hell I am going to do. Maybe Autolites? Where can I find those? NGK just said they only recommend that double platinum, does Autolite make double platinums?

-Dustin-

 

I just replaced th plugs in my car with NGK's and then my trans blew and shortly after my ignition started missing consistantly on a cylinder even with an active MSD 6aL IGNITION AND NEW TAYLOW WIRES. Now I have to replace the plugs and wires just to route out that as a problem. PITA Good thing I have headers and it should be a huge issue. Especially because the transmission is coming out too! I think I am going to try a set of tayor over the valve cover wires, extra thick, with ngktr6, Hope that works. If it does then I know a combination that wins.

If at first you dont succeed try try again and again.

 

I have a miss also from replacing my plugs...I should have called NGK before hand just to make sure.

I'll keep trying...Although I have become a pro at changing plugs with the stock manifolds

-Dustin-

 

Previous posts have suggested disconnecting the msda6 ,and see if the miss fire is corrected.Also,years ago,Criss Frezz mentioned that folks were blowing up those blaster coils a lot at the drags.Hope this helps.

 

Crane coils I think.

 

This knocking sound I get on acceleration, is that denotation? I think the NGK person on the phone said something about the tip on the GP staying to hot and pre-igniting...

-Dustin-

 

This is an interesting thread. Theres thousands of LT1s with TR55s, including mine. Kind of a weird thing to come out of the blue like this. Keep us updated.