Colder range spark plugs.

[Mars]

Hey all,

The local parts guys are tools around here,

What I am looking for is a part # for plugs that are 1 and 2 ranges colder than stock on a 2001 3400 V6.

I would prefer ACdelco.

I searched on the net and found Autolite 605 and 103 are both colder than stock...

What are you guys using? thanks.

[eliteweapons]

Are you running boost? I found a set of ngk irridium plugs for my 3100 but don't know if they will work on the 3400. these are for 20 psi of boost so they will be too cold if you are n/a. ngk stock #3690 the tr7ix series.

[pepsi_coke]

Yeah, hes boosted .. at least according to his WWW link ..

ROTREX blower C30-94

[Mars]

Yes 10 psi.

And, no one has part numbers for ACdelco's?

[RacerX11]

I?ll take a shot at this. The 3400 comes stock with AC Delco platinum?s, and these plugs are difficult to cross-reference. The number, 41-979, is not easily decoded. If you go back to a ?95 3100 (or older 3.1L, for that matter) that used non-platinum plugs, the listing is a R44LTSM6 (or R44LTSM for the 3.1). Here is a site showing how to decode this: http://www.acdelco.com/html/pi_plugs_ident.htm

The R is a resistor plug, the 4 means a 14mm thread, the 4 is the heat range (so 3 or 2 would be 1 and 2 heat ranges cooler), and the LTSM6 means it is a long reach, tapered seat, extended tip, special electrode, with a 0.060? gap.

So a plug one heat range colder would be a R43LTSM, two heat ranges colder would be a R42LTSM (I have only been able to find R42LTSM, so your options may be limited). I do not know what is special about the electrode on these plugs, or if the standard R42LTS would be compatible. I am also not sure if the 3100 and 3400 share the same plugs. I assume so, as the heads were pretty much identical. You might just head to the local parts counter and have them pull a stock replacement, along with a R44LTSM, R44LTS, R42LTSM, and R42LTS, and compare them.

Another option is to cross-reference the Autolite or NGX replacement plugs in different heat ranges back to a comparable AC Delco number.

Marty

[Mars]

Alright, I found a few things online, but not really confirmed...

I step colder than stock :

Autolite 605
NGKTR-6

2 steps colder than stock :

Autolite 103 (recommended for the 3.1 TGP, turbo grand prix)
Delco R42LTSM

Not sure what to get now, lol.

I have always been a Delco person, so I will go with the ones you suggest more than likely.

Thanks.

[Guest]

AC Delco R42LTS6, my plugs were for an '89 Firebird 3.8L Turbo.

[LQ1]

When I went to Napa and bought my plugs, I asked for a couple steps colder, and they said the Delco ones they had listed for my car were the coldest ones.

[Mars]

I got the Delco R42LTSM 's

They seem fine. Car is running better and better everyday. I can lay a patch patch now in second with 16 X 7 rims and 225 rubber without using the clutch on dry pavement. Couldn't do even close to that a couple days ago....