Which NGK spark plugs?
 

I try to stay up on headflow numbers, cam grinds, piston designs/weights, etc. I don't pay alot of attention to spark plugs. I had good luck with Autolite Plats in my '92 383 LT4, and sold it shortly after installing some NGK Iridiums.

Everyone seems to be using NGK TR55s in all these LS1/LS6s.
Are these the V-Power, G-Power, Platinum, Iridium... which ones? Any particular reason why--what is the difference (beside the obvious)?
I would rather hear from the Forum members, than the manufacturer's salespitch or a magazine's 'expert' advice.

Can I ASSUME we are using the stock heat range, .035" gap, and that LS6 P/Ns are no different from LS1?

I will be putting TSP longtubes on my '01 Z06 soon. Halltech, cam, 160 stat, maybe ported heads, pulley, THEN tuned, to come later.

Thanks, Joel.
(I do have a set of Bosch+4 Plats that were in my '92 for only a week)

Most seem to use the standard plain TR55 plugs - not the iridium, platinum, etc. The factory gap is NOT .035. You can run the stock gap (I think it's .060, IIRC) or maybe a "little" smaller, depending on your mods or lack thereof. I think most run a .055 gap with these plugs and close to stock power combos.

I personally use Tr55s on my H/C Z06. Now the part number for them is a 3951 from Advance Auto parts. I think they sell there for about 1.50 and O'Rielly normally has them as well just they cost more like 1.75. The Tr55s are gapped at 50 and are pregapped. They should be a v power plug. You really do not need anything more unless you do not wish to change plugs often. With the v power tr55s I change them at 15,000 miles. If you are running Nitrous or a blower then people move to the TR6 which has a 35 gap.

TR55IX's are the Iridium version, you'll never have to change them again unless you plan on FI or spraying.

If I remember correctly, the TR55's are copper core plugs. They won't last as long as the others but you will get good spark from them. NGK also recommends dropping one heat range for every additional 100 hp that the motor has been increased. When I installed my Dart heads, I went with a gasketed plug because that is what they were designed for, even though you can install either gasketed or tapered int he Dart head. Based on a recommendation from Katech, I went with the Denso Iridiums, but have your plastic ready as they are quite pricey. :eek:

The Iridiums shouldn't be re-gapped from what I understand.

:iagree:
The electrodes are too delicate and can break.

Joel TR-55's :)

TR-55s are a plain copper plug that works well. Don't remember any "V power" on mine, but they're 48K miles old, so things may have changed.

Have a good one,
Mike

Mine are most likely oem plugs and have 50k on them, should I change them?

Unless your engine is telling you via a misfire or persistent stumble that the plugs need attention, I see no reason. I pulled my OEMs at 100K and they were fine. Others haven't had that track record.

BTW, when I replaced mine, I felt a smoother idle for about the first couple of tanks of gas, then that familiar LS-1 lope returned and has been there ever since.

HTH, and have a good one,
Mike

My car runs fine, did the plugs come out o.k. after 100k?
Maybe I'll just trade up to a newer model with lower K's when I need maintenance.LOL.

Yes, somewhat surprisingly. Some people think changing out the plugs on a C5 is a nightmare, but after cutting my teeth (and hands, arms, etc.) on changing out plugs and wires on my LT-1 Z-28, it's a breeze!

I've always had success with using a breaker bar and spark plug socket and rocking the plug back and forth to loosen it. For sure, if it binds up on you, *DON'T* force it. Get some PB Blaster or other penetrant and gently work it out.

HTH, and have a good one,
Mike

Unless u run more than 70k, Then the plugs will be toast.
There is NO lifetime plug. There is no 100k plug.
They may still run, but the plug was shot long ago.
Tr-55's are a great plug!

If you're running N/A, the factory plugs are as good as any other.

Your plugs were shot. They just looked ok. The new plugs get better
mileage and power. at 100k no exceptions.

I wouldn't leave plugs in that long... Had 100k on my DD plugs and had a heck of a time getting them out as they had been in there for several years - even though I used anti - sieze when I put them in. You take a chance of damaging the aluminum heads threads. $.02 :cheers:

I did my plugs the other night (nightmare), they were 7 years old so they were a bit tight coming out, and not to mention I broke 2 plug wires taking them out (time to change anyway), but yes I did notice a better idle. I did the TR-55's @ .050 gap

Sorry to bust your bubble, but your stated differences (mileage and power) both saw no difference before/after the plug change. Got the records to prove it.

However, the point Tigershark makes about the plugs being hard to get out over time has some validity. I did change out mine after 100K miles, but they were there only 3.5 years when that happened.

Have a good one,
Mike