: Spark Plugs



paulikorg
03-14-10, 11:54 AM
Hi All,
Is there any truth to the claim by Bosch & E3 that their plugs
will increase mileage and/or make for a better running engine?
Does anyone have either of these plugs installed in their North* ?

Apprieciate any and all comments
Thanks
Pauli

Skiller.
03-14-10, 12:41 PM
Do not use anything by AC-Delco plugs (41-950). Our cars are very touchy to OE. I ran aftermarkets plugs for 3,000 miles and that was enough for it to start misfiring.

Plus, the Delco plugs are double platinum and last 100,000 miles!

Ranger
03-14-10, 02:40 PM
Is there any truth to the claim by Bosch & E3 that their plugs
will increase mileage and/or make for a better running engine?
No..

Submariner409
03-14-10, 04:03 PM
Once more, with feeling: NO !! and NO !!

As Skiller posted, use the AC Delco Platinum #41-950 plugs; they come pregapped to .050". Torque them to 13 ft/lb and use a tad of anti-seize on the first 3 threads. (FWIW, the Northstar plugs are sourced from DENSO in Japan.)

Use the diagrams to make sure the plug wires are connected correctly: it's important. Click to enlarge.

N0DIH
03-14-10, 04:05 PM
When you consider 100k (really that is low too) on stock plugs, the cost is pretty low.

My 96 Burb I bought used had stock plugs in it when I changed them @ 196k and it still ran decent. Stock plugs/cap/rotor/wires. (there are telltales for stock stuff, barcodes, stripes, etc).

Stock iridiums should be fine from the newer N*'s on the older ones.


Do not use anything by AC-Delco plugs (41-950). Our cars are very touchy to OE. I ran aftermarkets plugs for 3,000 miles and that was enough for it to start misfiring.

Plus, the Delco plugs are double platinum and last 100,000 miles!

Skiller.
03-14-10, 04:39 PM
Well, of course they can last longer than 100k..I think they have a 100k warranty.

tateos
03-15-10, 02:59 PM
I don't like to leave them in too long - I'm afraid they will get locked in and/or I'll pull the cylinder head threads out along with the plugs. I like to take them out well before 100K, clean up the spark plug threads, assess their condition for signs of engine problems, and then re-install with a little anti-seize applied to the threads. I had a plug get stuck 35 years ago in a '69 LTD 390 and I had to remove the cylinder head to get it out and I never forgot it.

N0DIH
03-15-10, 04:36 PM
Tis good wisdom, I still like to get the plugs out for inspection every 6 months or so, I use plain jane NGK TR5's in my 3800 L67 Supercharged. I might go with TR6's again this summer (less knock and more boost potential...).

Being I have iron heads, less of an issue, but alum heads, don't touch the plugs until cold and use liberal amounts of antisieze on the threads when they go back in...

My brother in law broke a plug off a Mazda truck 4cyl and had to pull the head to fix it. My dad and I tried and tried and couldn't get it out. The plug BROKE, pulled it out with all but the threads, they stayed in the head.... We tried easy outs and stuff, but nothing could get a bite to get it out. Imagine that on a Northstar with them long tubes to the plugs and back cyls you can't get that easy to? Not for me, pull them every so often, make it a spring/fall project...






I don't like to leave them in too long - I'm afraid they will get locked in and/or I'll pull the cylinder head threads out along with the plugs. I like to take them out well before 100K, clean up the spark plug threads, assess their condition for signs of engine problems, and then re-install with a little anti-seize applied to the threads. I had a plug get stuck 35 years ago in a '69 LTD 390 and I had to remove the cylinder head to get it out and I never forgot it.

tateos
03-17-10, 09:33 PM
What do you use to pull the boots on the right/rear bank of the 3800? My wife's 2004 GTP has around 50K miles and I want to pull the plugs and the right/rear bank spark plug wire boots just won't pull off and I can't turn them and I can't get anything in there that will pull them and my hands barely fit in there and I have no leverage....!!!!

N0DIH
03-18-10, 01:54 AM
I had a booger of a time with #2, that one didn't wanna come off for jack. I had a bad shoulder at the time (completely torn supraspinadus tendon) so I had a hard time, but kept working at it and working at it, finally got it. I think I did tear up the wire to do it.

The metal sleeves, pull on them, for the most part they will capture the boot and you won't pull on the wire. I have a Park Ave, so I probably have a bit more room under the hood too.

Same problem no leverage. Worst come to worst, you can go from underneath if you can get up there, then it might be better, not 100% if that helps, probably not. A boot puller I don't think has room either.

Ranger
03-18-10, 01:17 PM
I too had a devil of a time with my wife's. I finally got it done by hand. I was going to suggest the boot puller pliers, but NODIH might have a point.

johnny kannapo
03-18-10, 07:23 PM
What year was it they revised the spark plug from 41-900 to 41-950

Ranger
03-18-10, 10:42 PM
Not sure Johnny, but I think it was early 90's. Not sure what the difference is either.