120785 mile spark plugs

Okay....first, I have a '96 riv with 120785 miles on it. The spark plugs were never changed in over 12 years. They are the original stock AC Delco 41-921 spark plugs.

Today, I changed them to AL104's.

I started at noon and didn't get done till 6.00 pm...I would remove one, have a drink and a smoke, then replace it, replace the wire, have a drink and a smoke....you see the pattern here...by the time I got to the back plugs I was seeing double and thought I had a V-12.....but I digress,,,

Anyhoo...4 weeks ago when I had my stock wheels on, 225/55/16, if I would mash it, the tires would break traction...3 weeks ago when I put on my new wheels, 245/35/20 (each 8 lbs. heavier than the stock wheels), if I would mash it, no tire break....just a good sticky launch, but it seemed slow.

Today, after I changed my plugs, I had my wife drive WOT on a couple of runs, and from a stop to WOT the new tires broke traction.....

The old plugs looked pretty good for there age....no deposits or sludge, just a nice ashen gray, but there were "points" were it looked like they were arcing...

Heres the gaps when I removed the old plugs:

Cylinder 1) .066 - .067
Cylinder 2) .080 - .081
Cylinder 3) .066 - .067
Cylinder 4) .085 - .086
Cylinder 5) .067 - .068
Cylinder 6) .077 - .078


...I think I've been running on 4 cylinders for awhile....

Also...did any of your rear plugs have metal sleeves on them. like heat shields? Did you keep them or remove them?

all 3 should have sleeves. keep them on to protect the boots from heat.
have you had had the car all 12 years? just shows how durable platinum is, but not the greatest for performance.

Chicken wrote:

Also...did any of your rear plugs have metal sleeves on them. like heat shields? Did you keep them or remove them?

I kept mine on

Mine did not have heat shields , however mine were not the original plugs , but i have a feeling the original plugs and wires might have fared better than the cheap champions that were on there.

lots of performance shops use champion spark plugs. i think it was Rob that was saying he used them in their modified C6 corvettes.

Mr.Riviera wrote:

all 3 should have sleeves. keep them on to protect the boots from heat.
have you had had the car all 12 years? just shows how durable platinum is, but not the greatest for performance.

I did put the sleeves back on even though I used a new aftermarket wire set

The riv has been in the family all 12 years. I've had it since 2000, and know that no work was done on the engine prior to that.

I kept my rear heat shields on, and ordered three more for the front plugs.

Your gaps of .080" are pretty big, but still okay for a spark. Maybe not good spark, but I doubt you were dead missing on two cylinders. I've pulled some of my AL104s with gaps around .075" after 20k miles (originally .058"). You'll want to check yours next year, or at least by 20k miles.

Glad to hear your plugs look that good after 12 years! Interestingly, my original plugs were NGK unless someone changed them out before I bought the car at 24.5k miles.

I did not realize the Rivs dont have the heat shields on the front plugs.

I just checked the 00 Regal LS has them and the 99 Riv does not.

Bert:tavis:

Mark, I changed plugs a few months after buying my Riv, and also found a couple with burned out electrodes, and gaps in the 80's. Still ran ok, no missfires, just less than ideal.