Spark Plug Brands

Put in same brand and type you removed, gapped to appropriate size. May be a good time to also replace plug wires. And remember to apply the dielectric grease to ease the removal of the boots next time and apply anti-seize to the plug threads before installing. It will stop the seizing in aluminum heads.

Rob

There is no better plug for your GM engine than AC/Delco of the same designation as the original unless it is highly modified in some way.

|During the cold snap, I've noticed that the car seems to miss occasionally, |I pulled one of the plugs and noticed it's worn down..(tho no build up , |closer to black than light brown). So I decided i'm gonna to put new plugs |in.. I ask some friends what would be a good plugs to use and I've got |different brands depending on who I asked.. One said say away from Champion |Plugs because they tend to seize in aluminum heads, one said NGK's and |another said Bosh Platinum.. |Any info on which would be better for GM 3.8L(high mileage)?

I always used ACs in GM engines, with NGK as a backup. Nowadays, NGK makes a great many AC plugs, as well as the OE plugs that come in the car new. So I'd use whichever is cheaper, locally, since it's likely the exact same plug Rex in Fort Worth

"Rob >" During the cold snap, I've noticed that the car seems to miss occasionally,

Up until I installed a supercharger, I used bosch platinums in all my cars. I still use them and recommend them to everyone that says they need a tune up. Of course, the supercharged firebird uses ACDelcos

Good luck,

-Bruce

I have almost no experience with extremely cold weather, having lived in Texas most of my adult life. However, you should be very conservative about changing heat ranges today. The reason is that all the manufacturers went to copper-core or similar plugs years ago, which effectively widened the heat range of each one. Today, one step in heat range is equivalent to approximately 3 steps in the old plugs. So, one heat range takes care of a very wide range of operating conditions. Changing heat ranges will almost certainly take you well out of the optimal conditions, meaning you will either foul plugs or experience detonation. I use stock plugs in everything from road racing cars to tow vehicles. | |In cold weather (below 20 degF) you might need to use a plug that is a step hotter than recommended, especially in low speed driving or if you have a light foot. Don't make the gap too wide. I have seen some GM engines that recommend

035 in. gap in cold weather and .060 in. in hot weather. | |lugnut wrote: |> |> On Thu, 15 Jan 2004 12:38:58 -0500, "Rob" > wrote: |> |> >During the cold snap, I've noticed that the car seems to miss occasionally, |> >I pulled one of the plugs and noticed it's worn down..(tho no build up , |> >closer to black than light brown). So I decided i'm gonna to put new plugs |> >in.. I ask some friends what would be a good plugs to use and I've got |> >different brands depending on who I asked.. One said say away from Champion |> >Plugs because they tend to seize in aluminum heads, one said NGK's and |> >another said Bosh Platinum.. |> >Any info on which would be better for GM 3.8L(high mileage)? |> >

|> >Thanks ! |> >Rob |> >

|> |> There is no better plug for your GM engine than AC/Delco of |> the same designation as the original unless it is highly |> modified in some way. | |-- | Mike Walsh | West Palm Beach, Florida, U.S.A.

Rex in Fort Worth

Rob

Autolites are always good. I personally like Champion best of all, although some people swear AT them as much as I swear by them. The ones I swear at are Bosch Platinums.... wouldn't use them again if you PAID me to.

Thanks for the info.. decided to try out AC Delco Rapid fire , heard they good long lasting plugs.. Thanks again..

Rob

** This is good advive. In my Honda Civic I tried everything from Splitfires to Bosch Platinums and went back to NGKs. Best starting & best mileage of all. What more do you want from a plug?

Platinum plugs seem to trade optimal conductivity and performance for longer life. I'd only use them in a design which was difficult to change ... or one which specifically calls for them. Even then ...

... my '03 Nissan 2.5L 4-cyl uses a platinum plug right now and I am going to do some looking into something better (more efficient) as they look easy to change. Most 4-cylinders serve their plugs up to you on a platter.

I stay away from Champions (experience & reputation) and Splitfires were absolute junk. Began rusting right away and that gimmicky design did not improve my mileage. Bosch Platinums just don't seem to conduct well. Mileage went down with no noticeable improvement in power.

Stick with a good quality copper plug and change them at least every

20,000-25,000 miles for best efficiency. They seem to lose their edge ... when they lose their edges.

The NGK copper plugs have a notched center electrode and a slightly bevelled side electrode. Can't see why this excellent design wouldn't run well in any piston engine ... unless you got the heat range wrong.

--- Bror Jace

Here's where you contradict yourself, and I'll contradict you too. If the design was with platinum, stick with the original plugs. Nissans seem to get particularly peeved about non-OEM plugs. Stick with your first rule: use what the manufacturer suggests.

step hotter than recommended, especially in low speed driving or if you = have a light foot. Don't make the gap too wide. I have seen some GM = engines that recommend .035 in. gap in cold weather and .060 in. in hot = weather.=20

I'd be interested in knowing what kind of engines those would be.

How is their conductivity any different from any other plug???

-- Elbridge Gerry, of Massachusetts:

"What, sir, is the use of militia? It is to prevent the establishment of a standing army, the bane of liberty. . . Whenever Government means to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise a standing army upon its ruins." -- Debate, U.S. House of Representatives, August 17, 1789

If your car came with platinum plugs, you need to go back with platiinum. Depending on the design of the ignition system, some cars require a platinum center electrode, some a platinum ground electrode. The double platinum plugs (Champion) will work on both. the issue, as i recall, is spark erosion of conventional electrodes.

Rex in Fort Worth

Not sure whether it is the material or the shape/size of the electrodes but they don't seem to produce as effective of a spark. Less complete burn of the fuel/air fixture ... less power ... less fuel economy.

I'm sure there are folks out there who can expalin this better than I.

--- Bror Jace

I guess that leads to another question... what makes you think they produce a less effective spark?? , Less fuel economy, etc?? Have you seen actual data or is it just something people have told you?

-- Elbridge Gerry, of Massachusetts:

"What, sir, is the use of militia? It is to prevent the establishment of a standing army, the bane of liberty. . . Whenever Government means to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise a standing army upon its ruins." -- Debate, U.S. House of Representatives, August 17, 1789

Optimal conductivity? Most plugs have a resistor inside and the plug wires are also resistive.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs

Ontario

Platinums were introduced so you could go longer between plug replacements. The platinum plug gap does not erode like with standard plugs. Platinums typically fire in a smaller slightly more intense spark between tip and ground electrode. They usually give smoother idle at cold start-up if a car is a bit cold blooded. On a cylinder that has an oil control problem, platinums tend to foul out a bit easier so they can not be so good for an oil burner. They work absolutely great in jap motorcycles..makes the first few minutes after cold start much smoother and less choke needed many times.

Look it up. Platinum has a much lower electrical conductivity than copper.

I don't believe that its significant since the currents that flow in spark plugs are very small, and plugs have a deliberately built-in resistance much larger than the resistance of the tip material anyway for the purpose of suppressing radio interference. But its a fact that platinum is very definitely a third-rate conductor of electricity.