6.2 L9H 110k spark plug replacement - AAR

[intheburbs]

Well, even though the Denali was still running fine, I figured with 110k miles on it, the plugs were due for a change. Daughter has had it 800 miles away at college, and I frankly didn't want to do it during the winter, so I put it off until now.

The passenger side plug against the firewall was easier than I remembered. Frankly, the most difficult part was getting my hand back there to remove and reinstall the wire. Overall, the job took about an hour, I was in no rush.

When I pulled the first plug, the thing that struck me was the erosion of the electrode and the increased gap. But the engine was still running perfectly, with plenty of power. The next 7 looked very similar, and I'm actually very pleased with their appearance. Not really seeing any indicators of even a small issue with the engine.

Not a fan of iridium, went with Delco 41-962 plugs.

Next up: The Suburban. It has 192k miles, with lots of heavy towing. Will be doing those probably next month.

 

[swathdiver]

Well, even though the Denali was still running fine, I figured with 110k miles on it, the plugs were due for a change.

...But the engine was still running perfectly, with plenty of power. The next 7 looked very similar, and I'm actually very pleased with their appearance. Not really seeing any indicators of even a small issue with the engine.

Not a fan of iridium, went with Delco 41-962 plugs.

I put the OE 41-985s back in mine for the next 100K. What don't you like about the Iridiums and what do you like about the Platinums?

 

[avalonandl]

I think platinums dont erode as fast.

 

[intheburbs]

I put the OE 41-985s back in mine for the next 100K. What don't you like about the Iridiums and what do you like about the Platinums?

I think platinums dont erode as fast.

^^^Yeah, kinda that. I put iridiums in my '01 Burb at 100k miles, and by the time it reached 180k miles, it was running noticeably rougher. Replaced the plugs and they were a mess.

The Denali wasn't running badly, but the erosion on these plugs is a bit concerning. Granted, by my math, they've fired over 220,000,000 times.

 

[avalonandl]

^^^Yeah, kinda that. I put iridiums in my '01 Burb at 100k miles, and by the time it reached 180k miles, it was running noticeably rougher. Replaced the plugs and they were a mess.

The Denali wasn't running badly, but the erosion on these plugs is a bit concerning. Granted, by my math, they've fired over 220,000,000 times.

I remember in the 70' s replacing plugs at 30k and ADJUSTING POINTS.....

 

[Fless]

I still have a dwell meter and a timing light... just can't bring myself to give them up, although they've been in a box in the basement forever.

@intheburbs, what do you think the gap ended up being on the old plugs?

 

[intheburbs]

I still have a dwell meter and a timing light... just can't bring myself to give them up, although they've been in a box in the basement forever.

@intheburbs, what do you think the gap ended up being on the old plugs?

I checked with my gap tool, and was getting .055-.060". It looked a lot bigger than that, so I checked with my Brown and Sharpe calipers - got the same measurement. There seems to be a dimple on the bottom electrode that makes the gap less. Not sure if it's a different metal, or what, but it's certainly less eroded than the surrounding metal.

 

[swathdiver]

I checked with my gap tool, and was getting .055-.060". It looked a lot bigger than that, so I checked with my Brown and Sharpe calipers - got the same measurement. There seems to be a dimple on the bottom electrode that makes the gap less. Not sure if it's a different metal, or what, but it's certainly less eroded than the surrounding metal.

Swapped out the plugs in the white Sierra yesterday and they gapped to .049 after 140K miles. Wasn't running bad, just overdue for replacement.