spark plugs

[getnpsi]

Platinum plugs create spark at a lower voltage. Older engines need the biggest spark possible. I didn't know they wore coils faster? I just know they can create hesitation. Worse thing is no 2 cars are alike. Even the same model. You may never notice on one and another you do, so it's not just "my brothers friends dad's car runs like poo"---there is truth to it. As in the 2 other threads...buy the cheapest copper standard plugs.

[Zanzer]

Oh ya, forgot to add that. I run the cheapy Autolite Copper Cores in all my vehicles too.

My 98 Mustang actually prefers them over the factory spec'd platinums :thumbright:

[hotfordcat]

+2's in all my stuff.

[Zanzer]

I've never tried the +2's but you guys have me kinda curious now as far as running them in my Festy. I actually bought and ran a set of the expensive +4's when I first got the car but it had some freaky idle issues and surging. It went away when I switched back to the Copper Cores. Maybe it would be something to try with an aftermarket coil (?)

[CharlieZ]

Just to add a little tech talk: Assuming all other engine parameters remain the same, the things that effect the voltage level required to bridge the plug gap, the width of the gap, combustion chamber pressure, and to some degree, the conductivity of the metal forming the gap. Spark plug electrodes erode a microscopic amount with each spark. Like arc welding. Both platinum and iridium are excellent conductors. Manufacturers - first the Japanese - went to exotic ($) metals to prolong spark plug life. Platinum erodes slower than copper and iridium even slower than platinum. One of the reasons engines can go well in excess of 100K miles w/o changing plugs. This is a great positive for most folks, unlike us, who use and treat their cars as an appliance.

[kartracer46]

I've got the NGK Iridiums in 8ball and the NGK Platnums in Twizted. I have no complaints so far and the Iridiums actually made a bit of change in my fuel economy. Plus I have played with the gap settings too, that makes a big difference in plug performance.

[CharlieZ]

Plus I have played with the gap settings too, that makes a big difference in plug performance.

Only me thinking:

It seems a sparkplug set to the narrower end of the range (.039) would in effect advance timing by some small amount since the plug will fire at a slightly lower voltage. That is, in advance of where the voltage has built up to the maximum. Conversely, a wide plug gap would retard the timing because the voltage must build to a higher level to make the leap across the plug.

The numbers would probably very small in degrees since all of this happens in microseconds.

Does anyone have facts or figures to support or refute my thoughts?

[CharlieZ]

Forgot to add to my above post.
For the guys interested in "super-tuning," don't forget spark plug indexing. It's quite a process to determine how the gap and "J" contact should be positioned or indexed in relation to the intake valve though. It's different for each engine/combustion chamber designs. A search on the internet will reveal the procedure.
Just something else to consider when looking for that last micro-ounce of efficiency.

[kartracer46]

Forgot to add to my above post.
For the guys interested in "super-tuning," don't forget spark plug indexing. It's quite a process to determine how the gap and "J" contact should be positioned or indexed in relation to the intake valve though. It's different for each engine/combustion chamber designs. A search on the internet will reveal the procedure.
Just something else to consider when looking for that last micro-ounce of efficiency.

I used to index the plugs on my kart racing engines, it helps a 5hp briggs. Not certain what it would do for a car engine.

[jtugfestiva]

wow ok so i see iridiums, bosh 2 and 4, regular copper plugs. Ive tried all of them except the iridiums. So far im averaging 150miles per half a tank which is about 30mpg on an automatic. Well guys ill try the E3 in a couple of weeks and share the experience. gas is almost 5 bucks here in hawaii got to get all the help i can to save money.

[i218127]

After reading this thread, I took out the NGK Plats and went to the NGK IRIDIUM plug. I didn't realize they made them for this car. Set them to .044. They run very smoth all around. And my 35-65 and 60-75 axcel times are better. Seem to provide a little more torque. Just noticable.

i218127

[sc72]

If your running a high performance engine, indexing the plugs helps to shield the spark so it's not blown out, also if your running high compression, indexing helps to keep the electrode from coming in contact with the piston and bending the electrode and causing a misfire, etc.

[Oren09]

So from what I've gathered here, the iridium plugs seem to improve power and efficiency.
Iridium plugs are about $7 at parts stores vs $2 for plain copper core plugs.
I've heard of indexing and will attempt to do that when I change my plugs. Ill have an old head to use for referencing valve position.
Are the gains of iridium plugs great enough to warrant the higher price? If they have a noticeable and consistent gain of an MPG or two or more, that could over time pay for the initial cost. Or are the noticed improvements merely the result of new plugs and/or wires, not necessarily the plug metal?

[jtugfestiva]

Ok guys the verdict is in. Just bought the E3 spark plug and installed them. My car had new spark plugs in them NGK v-power. I always told myself a spark is only a spark and its not gonna improve combustion unless more fuel is added to the engine. Well as of now i notice more power up the same hill i go up every day, Faster starts, and the number one thing that ive noticed was less exaust smell during cold. This cant be just in my mind cause even my mom that drove it told me it drives quicker and she told me if ive done anything to it. Well if it doesnt work after a month ill be returning them for the iridiums and see how that works out. Ill keep everyone posted on mileage or if it blows the 1.3 to pieces.

[Eaglefreek]

Forget spark plugs, I'm waiting for an aftermarket laser system to come out.

http://www.autoblog.com/2009/07/15/gentlemen-start-your-lasers-ford-dumping-spark-plugs-in-favor/