Spark Plug Consensus

[yaz4real]

1999 Park Avenue Ultra needs a spark plug change at 82K..

Best for the money is?

[Alibi]

AC Delco plugs! Rapidfires are allright to use, but stock plugs work great too. Just don't use Bosch, whatever you do!

Oh, and the multi-tip plugs are a joke...

You might also consider replacing the plug wires if they're the originals.

[auto trainy]

Just a hint,the original got 82,000 why use any other. GM motors do best with AC plugs only and I would second that idea of changing the wires also with the original DelcoRemy.

[Greg5150]

I use regular Autolite (non-platinum) plugs and the car runs great. You will have to change regular plugs more often but your car will run better. Platinum is not as good a conductor as copper, but platinum will last longer.

[HotZ28]

I tried AC, Autolite, Champion and wanted something better, then I decided to try NGK TR55's and found they are the best for the plug for the supercharged motor. Quicker starts, better throttle response, better mileage & smoother idle, were all noticeable. What else could you ask for at less than 2 bucks a plug!

NGK Part # 3951 {V-Power Plug #TR55} Click Here for more info.
NGK Part # 7164 {IX-Series Plug #TR55IX} Click Here for more info.

[BNaylor]

Originally Posted by HotZ28

What else could you ask for at less than 2 bucks a plug!

NGK plugs for under $2.00 per plug Bo? Where did you get that deal at?

I use the AC Delco Iridium 41-101 which is the recommended replacement spark plug over the OEM AC Delco double platinums 41-921 or NGK PTR4B-15 double platinum spark plugs installed on some '99 and up L67 SII 3800 engines.

And the AC Delco 41-101 are made by............NGK.

[HotZ28]

Originally Posted by bnaylor

NGK plugs for under $2.00 per plug Bo? Where did you get that deal at

And the AC Delco 41-101 are made by............NGK.

I use the NGK # 3951 TR55 @ ($1.88 ea) shown HERE, since I like to keep fresh plugs in my car. I change them once a year (every spring). The ones removed, work & look like new, however, for 12 bucks a year, I never have to worry about plugs going bad! BTW, I think the AC 41-101 & NGK TR55IX are the same plug, however, AC Delco labels the plug as "Professional Platinum".

AC DELCO
· Nickel/chrome alloy electrodes resist wear from gap erosion and corrosion for maintenance-free service
· Hot-tip insulator heats fast and fires hot to resist fouling

Click Here for Part # 3951 NGK TR55

Click Here for Part # 7164 NGK TR55IX (Iridium)

Click Here for Part # 41-101 AC Delco (Professional Platinum)?

[BNaylor]

I think the reference (Parts America) is off or in error. AC Delco actually calls them Professional Iridium. The 41-101 are definitely Iridium and I am quite sure the same NGK TR55IX. Both NGK and Autolite have been secondary suppliers for GM/AC Delco for years now. If you look at the AC Delco Spark Plug Identifier Tables all 100 series are Iridium and 900 series are double platinum, both of which are supposed to be good for 100K miles, of course depending on driving conditions.

Autozone carries the AC Delco 41-101 Iridiums for around $6.99 per plug. I got them a little bit cheaper at the local AC Delco Authorized Parts Dealer. Although the OEM AC Delco 41-921 double platinums are discontinued you can still get them at some local GM dealers and they show up on EBay periodically.

As I pointed out earlier the original spark plugs for the '99 L67 SII 3800 (all Buick models) are the AC Delco 41-921 or NGK PTR4B-15 double platinums.

[HotZ28]

Advanced (Parts America) labeled the 41-101 as Professional Platinum, but the AC Delco site referes to them as Iridium. In addition, the AC Delco site, list the 41-101 as the only replacement "AC" plug for the 1999 SII SC Ultra.

[BNaylor]

Originally Posted by HotZ28

In addition, the AC Delco site, list the 41-101 as the only replacement "AC" plug for the 1999 SII SC Ultra.

How about a double

Although the AC Delco 41-101 Iridiums work fine and I haven't had any problems with them here is where I question why AC Delco recommends it as the replacement spark plug. For the VIN "J" GM 3100 and VIN "E" 3400 engines the 41-101 is also recommended. Whereas the orignal OEM spark plug for those GM 60 degree engines was the 41-940 double platinum. It seems like the older 900 series double platinums were more more closely matched to the respective engine.

My favorite alternative spark plugs are the Autolite Copper Core, single platinum (AP) and double platinums (APP). AL Copper Cores are great for modded L67 SII 3800 engines especially with supercharger mods like a smaller pulley to help control knock retard. The only drawback is they do not last as long as platinums or iridiums. They have an easy to remember numbering sytem for the different heat ranges. 606 (stock), 605 (1 colder), 104 (two colder), 103 (3 colder), etc. Plus Wally World (Walmart) has them for a reasonable cost.

[yaz4real]

Replaced spark plugs with NGK TR55IX ... in there was NGK laser 4B-15s. They did not look bad upon removal and 82k but thought a change was needed because of average 18.5 mpgs the last 6 tank fills.

Those 3 plug locations on the firewall brings cussing to a new level.

Thanks for the recommedations and replies.

[Greg5150]

Bob:

I usethe Autolite 606 copper core in my Park Ave and runs great & better than with platinum plugs. And you are right, the only draw-back is you have to change them more often.

[HotZ28]

Originally Posted by Greg5150

Bob:
I usethe Autolite 606 copper core in my Park Ave and runs great & better than with platinum plugs. And you are right, the only draw-back is you have to change them more often.

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