Re: Proper Way to Gap Spark Plugs?

This whole discussion of spark plug gaps brings to mind a time I was helping a guy's team get a "stock car" ready for some kind of race. That's a souped-up jalopy that guys work on with their bare hands and race on the weekends. Anyway, one of my tasks was to take the plugs from the engine the guy was using, and _cut off_ part of the ground electrode, such that it only protruded out to even with the centerline of the center electrode.

I've been wondering since then if that makes a hotter spark, but then the electronic tech part of me wonders, if those electrodes were, like, polished and filleted, would it make an even hotter spark because it would take so much more voltage to break down the gap, or would leaving them all jaggy and stuff make a hotter spark because the field emission would break down sooner, extending the time that the arc is alive?

Thanks, Rich

The smoother the gap surfaces, the higher the voltage required to ionize and then conduct (discharge). Smooth translates into just a touch of delay, in ignition systems, and just a tad more stored energy (some ignition systems).

Known as a side gap spark plug. May provide an advantage -if- the ignition coil has enough power to jump the increased gap. Clipping the side electrode also serves to un-shroud the spark in less than ideal combustion chamber designs.

Does electricity come in different temperatures?

There is no such thing as a hotter spark. Spark either occurs or it doesn't. As edges wear round, the spark is harder to initiate, this taxes the ignition coil.

On Fri, 11 Nov 2005 00:06:05 GMT, aarcuda69062 wroth:

It sure as hell does! Those "Fire Storm" glass globes with the corona all over the inside run on 20 KV or so and you can put your finger on the outside to pull all the corona over to a point just where your finger is. When I do that, all I feel is just a little heat, not uncomfortable. Try that trick with a neon sign transformer and you'll burn a hole in your finger real quick!

Back when my pride and joy was a '66 Ford Fairlane GT with a 390 cubic inch V8 and a four-barrel Holly carb, I used to us the half cut-back ground electrode trick and it really made a difference.

Then I added a capacitive discharge (CD) ignition system. I found that ordinary plugs, not cut back, but with a gap 50% greater than factory spec, worked much better.

A Kettering ignition system is just another example of a flyback converter and as such, obeys all the same laws of physics.

Jim

[snip] [snip]

Yup. These young bucks don't know what a real car is ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Forgot to add, I had a '67 Cougar and a '68 'bird ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

I'll remember that if and when [either] Fire Storm glass globes or neon signs make their way underhood.

Could be the less than ideal combustion chamber I mentioned earlier.

Totally expected results with a higher voltage but shorter duration ignition system.

Which young bucks would that be Jim?

That's pretty much everyone but me ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

"Charles Schuler" wrote in news: snipped-for-privacy@comcast.com:

But sharp points erode faster.

Note there are spark plugs with no protruding electrodes (fixed gap)on the market,some with multiple electrodes(2-4 ground electrodes).

--
Jim Yanik
jyanik
at
kua.net

I had a '68 Galaxie when I was 18. But the fuel prices here (plus my lack of dough at that time) meant I could only afford to drive it around the block *once* before having to sell it! Sounded great, though.

--

"What is now proved was once only imagin'd" - William Blake

Lincoln's market is the over 65 crowd. They're not much interested in sticks. BTW, the LS borrows much from Jag.

Same target audience. It was supposed to be a "retro" 'bird. I wanted one, but decided a hangar queen wasn't a very practical use for >$40K.

Yeah, I was a bit dissapointed in the T-bird after all the hype. I'd hoped they did for the 'bird what VW did for the bug. It didnt' translate all that well.

I found that out the hard way. As I mentioned here some while back, the data plate on my Vision TSI said ".062. I went throught a set of

*expensive* (and impossible to replace in cold weather) wires every year.

--
  Keith

A friend used that strategy on his daughters. On their sixteenth birthday he gave them the biggest gas-guzzler he could find. His reasoning was that he'd rather they drive than one of their friends, rather they drive the biggest hunk-o-metal on the road, and they couldn't afford to drive too far.

--
  Keith

ground

Operating cost wasn't an issue for *him* either (owned a pot-full of real estate around town). It was for his girls though. ;-)

--
  Keith

My daughters started with a Torino (late '70's)... operating cost wasn't an issue... I just wanted them protected by a tank ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Hmm. Teaching them to protect themselves by driving defensively is too liberal, I suppose.

Thanks, Rich

No, but SPARKS do :-) Remember, the spark isn't "electricity," its a super-heated plasma caused by the electricity passing through the surrounding gas. The higher the peak current that flows in the spark, the hotter the plasma gets.

I had a '68 Ranchero, and its part of what drove me to Mopars :P I actually miss that ugly thing sometimes.

Seriously, though, I had good friends who had a a 390-powered '64 Galaxie and a 390-powered '63 T-bird, and those were amazing machines.

Given the choice between a WRX and ANY 60s Ford (especially with a big-block) I'd take the Ford in a heartbeat. But I wouldn't trade my '60s Mopars for a Ford... ;-) The one thing to a WRX's credit- it does sorta *sound* like a real car. The opposed engine has a melodic exhaust throb instead of just a phart sound like most 4-bangers.

On Mon, 14 Nov 2005 12:24:58 -0600, Steve wroth:

Thanks to a rusty old Mustang that couldn't stop when I did (red light) I got a bent up muffler on my WRX. Replaced it with a Borla cat-back exhaust system, 3" pipes, and their sweet sounding muffler. The total cost was the same as a new stock muffler alone!

Now my Rex sounds as good as it looks and drives.

Jim