Changed Spark Plugs

bcfitzsimons · October 31, 2002

I got off of work early yesterday, and with nothing to do . . .

I figured I change my spark plugs in my 8.1L since I've recently decarbonized the engine with top end cleaner.

Now, mind you, I've had gasoline quality problems recently, and the truck only has 15000 miles on it-

The platinum stock Denso sparkers were terrible. Coated white and brown, with gobs of crusted carbon stuck at the angle where the electrode meets the body of the plug. Carbon all around the cylinder end of the plug too. The center electrodes on all of them were coated white except for the tip where the spark originates. Most also had layers of tan deposits on one side of the tip and the electrode. The only thing I can think of is that, with decarbonizing, the side of the plug that faces the intake valve got cleaned, but the exhaust valve side didn't.

Needless to say, I never believed in the 100,000 spark plug in the first place; this, however, just serves to confirm my belief even further.

There were a couple of good things that I noted while I was changing the plugs:

1) it was REALLY easy to do. The only difficult plugs are the two that abut the steering shaft. However, a good plug wrench did the trick.

2) total change time was 1 hour, 10 minutes from start to finish :thumb:

3) throttle responsiveness is WAY up.

Fitz

taki1 · October 31, 2002

what brand did you replace them with?

bcfitzsimons · November 1, 2002

Champion Copper Plus. I figured that since the platinum fouled so fast, why waste the money? Besides, the Champion copper plugs are built for high voltage ignitions, and deliver a stronger spark than platinum spark plugs (supposedly).

The motor's as smooth as the day I drove it off the lot.

Fitz.

maggot · November 1, 2002

BC,

How does it run with the old fasion plugs any difference any difference in the sound ? I hear they work better and I was thinking of trying the old fasion ones in my 6.0L. Does anyone see a problem with this, other than having to spend a couple bucks and an afternoon with a 6pack and my truck ? Any reason under the hood is a good one for me. I would not think any plug would go 100K and have questioned that.

bcfitzsimons · November 1, 2002

Now that you mention it, it does sound a bit throatier now that the new plugs are in. I don't know if that's because there's proper combustion going on now, or what-

Fitz.

CMNTMXR81 · November 1, 2002

The old fashioned style should work smoother than the platinums simply because they conduct electricity better than platinums.

That's why platinums are *supposed* to last 100,000 miles. They resist firing, resisting firing means the spark kernel isn't generally as strong, spark kernel not as strong = less wear on the plug.

Going to a softer metal, more conductive plug will help performance, economy, smoothness, etc, etc, but they will have to replaced a lot sooner than 100,000 miles.

BTW, I've never believed in the 100,000 mile plugs myself. I usually change them right away.

woyster_00z71 · November 1, 2002

I just changed the plugs and wires in my 1997 with 98,000 miles on it. Never touched anything till now since there were no problems, just doing preventative 100,000 mile tune-up. Anyway, the stock plugs looked great when I took them out. Nothing problematic whatsoever. I haven't checked the Silverado's plugs but would hope they are fine at 58,000.

B.J.

maggot · November 1, 2002

I think CMN makes sense. If tittaium and plat. is so good, how come the fastest computer chips are copper?? Same principle. You think pretty good CMN.I put the bosch palts. in a 1991 s10 2.8 and it acted goofy. On my 3.1 at 89K miles I change plugs, they were shot and about 50K over due.Put copper in and it has been fine. Evey motor is going to be different, but dollar for dollar I think the good olds ones are fine, and the price let's you change them more often. Just like oil, I use dino and change it like underware. Airfilters too, AC and change often. I am getting ready for a long trip pulling my wagon, I may pick up 8 oldies and try them out. If I do I'll let yall know my results.

CMNTMXR81 · November 1, 2002

It's all about resistance man...(holding up the peace pipe)

I don't want those like woyster that went nearly 100,000 miles thinking that I think those plugs won't last. I simply don't believe in them, that's all.

I've seen just as many of those 100k platinum plugs come back at 100k and they were nearly impossible to remove and once removed didn't even resemble a spark plug past the threads as I have perfect ones. It's really 50/50.

Another thing I should note is that some ignition systems (namely FWD GM V6 cars) are very tempermental when you start changing resistance of the plugs by changing the type you put in.

02 2500 Avalanche · November 2, 2002

Thanks for bringing this up. Im going to check mine this weekend as I just hit 35k miles. Any idea on what is exactly the best copper tipped spark plug to replace the stockers with? thanks

Alex

bcfitzsimons · November 2, 2002

I don't know which brand is the best, but I used Champion Copper Plus and I'm pretty happy with the results. Champion also makes a gold spark plug, which would probably be better for performance, but $$$-wise might be just as expensive as platinum plugs. I'd bet that as long as you stick with a major brand, you won't be disappointed.

Fitz.

02 2500 Avalanche · November 2, 2002

I checked the plugs today, sure enough there was quite a bit of build up on the exhaust side of the plugs. Off to Auto Zone I go

Alex

bobc · November 9, 2002

Hey guys, I'm pretty new to this forum. But I've just had plugs changed in my 2001 Silverado 1500.

I've been fighting an occasional smoke at startup problem. So I took the truck to the *Volvo dealer* where I bought it, used, and they tried to track down the problem this past week. Truck has 44k miles on it so it's out of factory warranty.

They pulled the plugs and found 1 very badly fouled plug and the rest were very nasty. The observation was that the plugs looked like there has been a lot of preignition and carbon fouling. The service manager asked if I was using bad gas or pulling a heavy trailer... My answer was "no" to both. I'm using 89 octane (chevron). He suggested trying 91. No prob, if anything maybe the better additive package of the Premium fuel will help with carbon deposits. The truck does ping pretty bad if I really jumped on it and the first time that I heard that I tossed a 1/2 tank of 91 in it. No signs of oil fouling on the plugs. No chip or Hypertech remap that I am aware of, so I am surprised it's pinging. Maybe bad knock sensors...

One observation with the new plugs, the truck runs differently now. It feels to me like it's running leaner, throttle feels "soft". It's also not dropping out of OD/clutch lockup if I give it 1/3-1/2 throttle at about 50mph. It's strange, I feel the motor rev up a little, then it feels like the torque converter locks up so it feels like it's in too high a gear to accelerate. It never did this before these guys worked on it. Not sure what that's about. I seriously doubt they could have updated/reprogrammed the computer becuase they aren't a GM dealer.

They didn't figure anything out about the oil smoke problem. I guess I'll just keep a camera in the truck and prepare to take a picture everytime I start it.

Forum is cool and I've found lots of good info here.

Later!

bobc