: Improper Sparg plug gap, what happens?



highonchai
01-17-06, 09:35 PM
I'm going to change my plugs and wires this weekend. And i was wondering what would happen if I didnt gap the spark plugs correctly? Ok, other than me being a total idiot for not gapping them properly. im sure the car will run a bit rough, burn too much fuel maybe? but can it damage anything?

zonie77
01-17-06, 09:43 PM
If you are close it'll be fine.

If you get too big you'll get misfires. If you get too small you'll get misfires.

eldorado1
01-18-06, 12:22 AM
our old buddy says that it changes the spark timing. Larger gaps take more time for charge to build before they fire, so it retards the timing.

This indirectly effects emissions and idle quality among other things.

lry99eldo
01-18-06, 12:33 AM
Use the wire from a large paper clip. They are about .050 to .053 in diameter. If they are pre gapped and haven't been too shaken up the gaps will be close to this. If the wire fits through snug that's cool, but if it falls through, just let the weight of the plug close the gap by lifting it 2 or 3 inches off a hard, stable, smooth surface landing at a slight angle favoring the tip of the grounding strap and drop it a few times. A few "drops" will close it slowly and safely. I don't suggest buying any special tools and if you purchase them at a parts counter they may gap them for you. They should go another 100K miles, so is it worth it to have a tool or two laying around that long? Also, do not pry the gap open against the center electrode, use a metal fork and slip it over the grounding strap close to the 90 degree radius at the weld joint and slightly twist the fork handle to force the strap upward slowly away from the electrode and porcelain. You'll see what I mean.
lry99eldo

lry99eldo
01-20-06, 08:40 AM
Here's a link to what I think is a good article on Platinum plugs and plugs in general as well as wires.

http://www.babcox.com/editorial/cm/cm120032.htm

lry99eldo

Katshot
01-20-06, 09:08 AM
Not a bad article but he's wrong about Platinum being such a great conductor. The facts are that Platinum is actually not that great. That's why nobody uses it in performance applications. Matter of fact, most straight performance applications stick with straight copper because of it's great conductive properties. Unfortunately, that is NOT a great idea for a street car since it's extremely low resistance will make listening to your radio virtually impossible, and can even affect many serial data lines throughout the car that will pickup the EM flux from the high-tension ignition secondary system like an antenna.
From what I've seen Iridium is the best of the new materials being used. It is better for performance than Platinum due it's lower resistance, yet still more than durable than the Platinum.
As for installing plugs, the gap is critical for emmissions, gas mileage and overall performance. The accuracy of your gap will have a direct effect on these areas of operation, so if you want the best of these areas, be as accurate as possible with your gap.
But that's not the end of the issue here. The plug gap is but one piece of the puzzle that is the ignition secondary system. Every point at which there is a mechanical connection that electricity must flow through, you risk problems. For that reason, it's very important to make sure that these connections are as clean, dry and tight as possible. A cracked plug, loose plug wire, or worn coil will create FAR more problems than any slight deviation in plug gap. So be very careful that the plugs are installed correctly, the wires are in as near to perfect shape as possible, and the coil shows no evidence of wear. Electricity is very lazy, if there's any possible way for it to get to ground other than jumping a plug gap, it will. And even intermittent short trips to ground can cause big drops in performance and fuel mileage.
This is why I generally suggest replacing wires when you do plugs.

lry99eldo
01-20-06, 09:34 AM
Good advice Katshot. So many people forget about those "connections".
The statements in the article about platinum being a good conductor, I read it as saying that it is a good conductor, not the best, and that it's use is for durability and longevity.
For performance all I've used in the past has been standard AC's hooked up through an MSD unit of varous models depending on need. And I changed them like they were Kleenex. And of course, the less mechanical parts and connections the better.
RFI was always a battle with race cars as they got and continue to get more sophisticated, yet that seems to be under control with good placement of components.
lry99eldo