Plugs from ACDELCO

[JacksonvilleDeville]

So i am about to do a tune up on my 96 deville, and from what i know i should go with AC Delco plugs, ok cool. So my question is which ones? Which ones and why?

# Iridium
# Professional Platinum
# RAPIDFIRE® Performance Platinum
# Conventional

These are the options? Is there anything wrong with using Rapidfire performance platinum? I have no idea what they are, and i am sure the cost more, but they sound cool. Are there any known pros and cons of these or other plugs?

My engine runs a little rough these days at a light or idel. The other day i took one of my plugs out to see when they looked like. Can anyone tell me what the white build up is? looks like white cooked on powder.

Thanks for reading this post guys.

[zergkiller]

You'd better use the plugs that are specified by the manufacturer. I tried some plugs that the computer from AutoZone said were correct and had to do the job right over again. I had codes, lights flashing on the dasboard, and the car stumbled, had no pickup, and died at lights.

No tricks this time. Just the standard plugs will work.

Mine is a 2001 DeVille, by the way. The four pole things really didn't work at all. I couldn't drive the car at all.

I think the white powder is lead from the gasoline. As long as you don't see too much black buildup, or, heaven forbid, oil on the plug, they sound fine.

[Ghost C]

No idea what plugs are best on the Northstar, but a search should net some answers. As for reading spark plugs, here you go.

[cadillac_al]

Ahhh, the old spark plug chart, I think that was printed in the 60's. You will never see a modern car with plugs that look like any of them. They are usually pretty white nowadays so all you can do is look for the electrode wearing down. I would skip the conventional plugs and get the cheapest of the other three. You don't need double platinum plugs but they won't hurt anything if the sales guy talks you into them. I'm not too familiar with the AC's anymore because I have used Bosch Platinums for 15 years with no problems and they are half the price. If you used Bosch Platinums you might be dis-owned by this board though lol.

[Ranger]

A/C Delco 41-950 dual platinum tipped. Your engine uses a waste spark ignition. It fires each plug on both the compression as well as the exhaust stroke. The spark is reversed on one of those stokes so you need the platinum tip on BOTH electrodes.

[submariner409]

The recommended plug for a 1996 Deville is an ACDelco #41-950, currently $5.76 each in an 8-pack from www.rockauto.com . That is tagged as a "Professional Platinum" plug and comes pregapped to .050". Others have tried a variety of plug brands and electrode configurations with varying degrees of success. Your best bet: Stick with what the engine manufacturer recommends.

Follow the 2 diagrams exactly or you'll have a nagging miss that will drive you crazy. As Ranger said, Google "waste spark ignition" and read up on what you have.

[JacksonvilleDeville]

Thanks guys that's some good information. I think i will go with Rangers A/C Delco 41-950 dual platinum tipped, those sound about right. I think the last plugs that i used were the ones that auto zone's computer told me to use. Do not remember which ones they were, possibly bosh.

[cadillac_al]

Originally Posted by Ranger

A/C Delco 41-950 dual platinum tipped. Your engine uses a waste spark ignition. It fires each plug on both the compression as well as the exhaust stroke. The spark is reversed on one of those stokes so you need the platinum tip on BOTH electrodes.

Whoops, I thought the Northstar had a coil on every plug. I guess it does need double platinums then.

[submariner409]

Depends on what Northstar you're talking about. Up to the 2000/yr turnover, the Northstar had a 4-coil waste spark system with its specific crankshaft reluctor and same-type CKP's, plus a separate ICM under the 4 coil pack, each coil with 2 plug wires. 2000 saw the introduction of the 8-coil COP cassette installation, along with roller cam followers, no plug wires, different PCM, staggered CKP's, and a host of other emissions and basic engine controls.

Pre-2000, apples. 2000+, oranges. 2004+, pomegranites.

Ranger edit:.......and they all like ACDelco Professional Platinum plugs. (actually, the overseas arm of ACDelco contracts: Denso, the OEM plug supplier to GM Northstar.) I have fooled with Robert Bosch plugs since 1954. They still aren't worth a hoot. NGK Iridium plugs are the cat's meow in an Olds 455. Not worth squat in a Northstar.

[Ranger]

The 2000+ does. COP (Coil On Plug) ignition. Pre 2000 has one coil for 2 plugs. Thus one on compression stroke and the other on exhaust stroke.

EDIT: Sub types faster than I. He also explanes things better.