when gapping the plugs, how good are those $.99 slider gappers? i would think that they might damage the center electrode or that they're not too accurate, since they're only 99 cents. also, what would happen if my plugs are gapped + or - .010"? just out of curiosity.

 

There's a saying on the blue side....

"Don't nuke simplicity"

If a spark plug gap tool was $25 bucks you would be complaining it cost too much do to such a simple task.

If plugs aren't gapped correctly, it will significantly shorten their lifespan and your engine will not run efficiently.

 

also... how can a plug be "pre gapped?"

Different cars use the same plug, but not all of them have the same needs....

Im really not sure about this... i dont gap them i just melt them tongue.gif

 

Most spark plugs come "pre-gapped" but it's always a wise idea to check them.

#1. The part number on the end of NGK plugs incidateds the gap. In the beta's case "11", that means 1.1mm or 0.044"

#2. The round spark plug gappers SUCK. They always measure the gap at a "slant" due to the ramped design of the product. Always use flat feeler gauges

Something like this

Only 6.99 from www.craftsman.com
Sears Item #00940811000
Mfr. Model #40811

They are well worth the $6.99 you pay for them. Keep them well oiled(with motor oil) or they tend to corrode or stick together.

If your plugs are gapped to narrow, the spark will not be long enough or strong enough to ensure complete combustion. A gap that is TOO large can cause no spark, coils to burn out, the spark itself can be "blown out" leading to no combustion event.

Always gap your plugs per the manufactuers spec, unless you know what you are doing, and have a damn good reason to increase or decrease gap.

In turbo cars, it is common to DECREASE the gap with stock ignition systems to ensure that the spark can jump across the denser air/fuel mixture. Failure to do so can lead to weak spark or the burning out of ignition coils, or spark arcing in the wires/coil.

In powerful aftermarket ignitions, you can increase the spark plug gap to get a bigger, more powerful spark.

Again...only do this if you know what you are doing, and have a damn good reason to mess with the spark plug gap.

In testing with my turbo, I LOST power by going with a smaller gap (0.025 to 0.035).

[ December 06, 2002, 09:25 AM: Message edited by: Random ]

 

For sure!

first time I changed plugs (on my old sunbird) I took a friends word for it that pre-gapped was fine.. even though I had read a book (Automotive repair for dummies.. please don't laugh too hard) that recommended regapping.

After he helped me change the plugs, (I had never gotten my hands dirty on an engine before) I got in the car and drove away. I was quite used to being able to easily squeel the tires with the automatic 6cyl.. but I had trouble accelerating at all, and on the highway had trouble getting it to go faster than 90km/h. I turned back around, parked the car, called my cousin (who happens to have a gapper for a keychain). He showed up, I regapped them, and it worked like a charm.

lesson learned.

 

This is funny, a buddy in one of my classes here at school asked me about this same thing a couple of weeks ago. I had the same answer as Random. $6.99 isn't anything compared to having a car running at its peak. Neither is a little time re-gapping before install. Just spend the 7 bucks, take 5 minutes and check the gaps on all four (or six) plugs before install and go about your business.