Plug Gap - Silly Question I'm Sure

[texasz]

Ok, I know that plugs have to be properly gapped before installing. My question a two parter and is this:

What happens when a plug gap is too small?

What happens when a plug gap is too large?

[Zs-ondabrain]

If the gap is too small, the spark will be small, as the .032 provides a wide enough area for the spark to get hot enough to create a better burn.

If the gap is too large, either the spark will not reach from the electrode to the bridge, or, if it does, it's power will have been spent before it makes it to the bridge.

I have the Mallory Promaster coil and the MSD 6AL. The two together gives me more than Double the spark power. My plugs are gapped at .065 and I can go even bigger if I want.

So, going with a bigger coil than stock (Blaster 2) will allow a bigger spark and wider gap. The bigger spark and larger gap increases fuel milage, Horse Power and better emissions. the reason for this is Better Burn. the best fuel milage is produced by the best burn of the least amount of fuel. Increasing spark allows for an increase of fuel, which increases Horse Power. You get the idea.

Hope that helps.

Dave

[JonnyRock]

Dave's right.

If the gap is to small, the spark will be too small and not develop a sufficient flamefront.

If it's too big the spark won't bridge the gap. This is because air is an insulator and has a relativley high electrical resistance.

On a related note, multi pronged plugs don't create multiple sparks. The plug fires exactly like a normal plug and the spark jumps to one of the prongs. The benefit of multiple prongs is that the spark has a number of paths to choose from and one may be less resistant at that moment. They may also cause less wear on the electrode.

There are systems that fire multiple times during a single combustion event (like on my explorer) but again, it's one spark at a time.

Edited May 31, 2009 by JonnyRock

[texasz]

Thank you both for such a complete answer. I suspected as much about too small a gap, it was the larger gap that I really was unsure of.

Once again, Dave you have really helped me. Your explaination of the stronger coil, higher economy, et al is GREAT! I had never known those things before. You can bet I'll adding this to my (very long) list of things to do to my Z.

JohnnyRock, also interesting about plugs like the split fires...I thought that the spark hit both at the same time. I didn't realize it only hit one.

See, you can teach an old dog new tricks. :laugh:

[Zs-ondabrain]

There are systems that fire multiple times during a single combustion event (like on my explorer) but again, it's one spark at a time.

And that's what my (or any one elses) MSD does. As the name says "MSD Multiple Spark Discharge" It basically sends multiple signals to the coil. The more sparks in each cylinder per compression stroke, the better combustion, the better combustion, the more horsepower and fuel economy you'll get.

That's why I'm such a stickler for good grounding and power distribution. The better the signal, the better chance of the equipment operating properly. Also, The splitfire plugs can be compared to 2 antenna's on a roof top, lighting is only going to hit one of them at a time, but nver both simaltaniously, unless they are very close to each other.

And properly working equipment is what we're all about here, right?

Dave

Edited May 31, 2009 by Zs-ondabrain

[sblake01]

That's how an MSD ignition works but I was always under the impression that MSD stood for 'multiple spark discharge' so I just googled it and that's what the MSD site says in it's 'MSD History' section of the site.

[Zs-ondabrain]

Fixed. I was talking to someone about power distribution blocks taday and got it stuck in my head. So call it a slip.