View Full Version : For what it's worth--Smokey's outlook on spark plugs...

12-08-02, 07:50 PM
I've been reading Smokey Yunick's autobiography, "Best Damn Garage In Town (http://www.smokeyyunick.com/)" and came across this section regarding spark plugs and Smoke's testing results. Take it for what it's worth - I happen to have a lot of respect for Smokey Yunick.

Bear in mind that it is written in "Old Southern Racing English." ;)


'Bout 1980 mutiple spark plugs reared its ugly head again for about the tenth time. So this time I got an air cooled one cylinder motor cycle engine and made a head for it with five spark plug locations and run it with two magnetos, each firing one or two plugs at once. I found that one plug in right location did just as good as four at once. But I found in artificially aspirated engines with high boost and high rpm (firing), mutiple spark plugs reduce misfires percentage and simply stated makes a little more power with increased durability, but for a Winston Cup engine, once you get in right place, one plug will get it done just fine.

I spent a lot of time experimenting with various types of electrodes on spark plugs, spark plug gaps, diameter of center wire, center wire radiuses, center wire flat multi-ground electrodes, surface gap. flame ignition or plasma ignition. Various ceramics qualities in regard to dialectric strength, heat range, center wire sealing and the battle to remove all moisture in the center wire seal area. Remember I worked as a consultant twice for Champion spark plug. Matter of fact the first complete Champion plug lab with dyno was at my place 'bout in 1957 time frame and came back as a consultant again in the early '90s. So you could say I am half way qualified to talk spark plugs.

I found small diameter center wire and a glass seal the best. The ceramic material formula and heat treat are very crucial to dialectric strength. Sharp edge flat center electrodes are the best, rounded electrode is very negative. More gap, say like .075 is best, but takes a very good ceramic with a no moisture center wire seal and a strong ignition in amperage and duration. This then puts plug wires in trouble reference leaking. As a rule no plug wire can handle it as good as a wire with added protection from a premium wire shield like Moroso blue. Seems like mutiple ground electrodes are a little better, less misfire, especially late in race when oil control weakens. (This is not a power tool for round track racers.) This was durability medicine. I found we as a rule used too cold a plug.

I think ceramic should be 'bout 1100F for best ignition, the heat reduces the chance for misfire because of oiling or incorrect air fuel ratio. Plug gap should be all the sytem can stand reliably. I believe in individual coils for each cylinder with no plug wires. Here's a five cent tip on coil or condenser reliability: if either one gets so hot it burns when you touch them that engine will soon quit making noise. Remember it's harder to transmit electrical energy in elevated temperature without a significant loss of voltage also.

Comparing a three foot plug wire to a one foot plug wire, about half the voltage is lost. Now this information is nowhere's near as critical to normal surface transportation engines as in state of the art racing engines. With a coil per cylinder we run without plug wires so I did the best I could. I plugged into spark plug surrounded with a heavy silicon boot for mechanical and dialectric strength and a sleeve which increased the dialectric strength of the wire. When we had to run plug wires.

How 'bout platinum or other precious or exotic metals for spark plug electrodes? My experience is these expensive metals add life and durability, but for say a 500 mile Indy race they wouldn't be any advantage at all because all the race plugs are replaced every race. Where mutiple electrodes are part of the design only one pair of electrodes will react, that being the pair (current and ground) that offer the least resistance, so mutiple electrodes offer one advantage, optional electrical path in case of fouling of the normal or primary pair.

The spark plug is now damn near 100 years old, and essentially the same since day one.

Flame or plasma will react a much greater range of non-stochiometric cylinder charges.

Only predecessor a spark plug has would be striking a pair of flint stones, or rubbing sticks together.

12-10-02, 02:58 PM
Yup, Smokey had it figured out - all the plug does is light the fire, and once it's lit, it doesn't need any more help. All the marketing hype on "miracle" spark plugs drove him nuts! Smokey was a frequent "back-door" visitor with us at Chevrolet Engineering in the 60's when I was in the Corvette Group - Helluva guy! ;worship

05-05-04, 03:56 PM
Yup, Smokey had it figured out - all the plug does is light the fire, and once it's lit, it doesn't need any more help. All the marketing hype on "miracle" spark plugs drove him nuts! Smokey was a frequent "back-door" visitor with us at Chevrolet Engineering in the 60's when I was in the Corvette Group - Helluva guy! ;worship
Ya got that right JohnZ,
I often have to smile to myself when going to meetings and looking under some hoods of cars belonging to people that I thought had better sense than to throw their money away. They would almost be better trying to light the cylinders with flaming $10.00 bills. It would probably cost less. I'm of course speaking of vehicles whose engines are pretty much factory stock.
I'm pretty happy with what Chevy chose to ignite mine with.


Tom Bryant
05-09-04, 05:24 AM
Anything Smokey ever said you could take to the bank. You knew that he had researched it from every way possible including several you wouldn't even think of.

05-26-04, 08:42 AM
I'm glad this got thrown up. It's funny how much hype marketing can stir up. Manufacturers recommend certain plugs for a reason, they have been tested and work the best. I run the cheap, 50 cent, autolite plugs in my truck and couldn't be happier with them.:)

06-24-04, 01:24 AM
in my bronco I run one heat range hotter (lots of idle driving) in the vette I am running the crazy metal plugs, I hate changeing plugs in the vette come to think of it I hate changeing them in the bronco....

05-04-05, 04:48 PM
The subject of spark plugs has been coming to the forefront again lately, so ... Bump! ^^^ :w

05-05-05, 02:20 PM
Ken, my wife got me the three-volume "Smokey" set for Christmas, but I haven't had a chance to dig into it yet; will bring back lots of memories when I finally get started on it :)

05-05-05, 02:48 PM
I have been reading it also from time to time. I once subscribed to Circle Track just to read Smokys column. He was one of a kind.

05-05-05, 03:01 PM
Smokey was the best! a born engineer ( with out the degree) that I as a mechanic could respect!

05-05-05, 03:42 PM
Ken, my wife got me the three-volume "Smokey" set for Christmas ...You'll like the book, John.

05-10-05, 10:27 PM
Thanks for that post and the 'trailers'. There are a few shops and mechanics who speak (no BS) like Smokey, but they are hard to find.

I ran a set of JC Whitney Fire Injector plugs in my '66 MB230 and loved them. They had multiple grounds, as the outer ring looked like a castle. Those plugs lasted for nearly 100k, long before 100k mile changes became common.

05-13-05, 09:48 PM
Smokey has teamed up with Robert Krupa to develop the "Firestorm" spark plug.


05-14-05, 01:24 AM
Smokey has teamed up with...Smokey may have once teamed (past tense) with Bob, but Smokey's dead now. ;)

Why must I always nit-pick? :L

Anyhow, thanks for the link. Interesting design. :cool

05-14-05, 02:13 PM
"FireStorm's Capabilities
First, let's look at what Krupa's FireStorm spark plugs give an internal combustion engine:
More horsepower;
4450% increase in mpg;
Dramatic decrease in emissions.
Second, let's see what FireStorm plugs eliminate:
Smog pump;
Catalytic converter;
Radio frequency interference (RFI) and the use of resistors in the centre electrode;
Gap growth;
Exhaust gas recirculation (EGR) systems;
Misfire/hesitation/detonation/stutter and stumble."

HOGWASH! If any of this was true, every auto manufacturer on the planet would be all over this like ugly on an ape, and would pay the bill to tool it up instantly, and would kill each other for the patent rights.

"The spark plug companies hate me..." Sounds like the same tune that was sung by the guy who made all the wild claims for the Fish carburetor and claimed "the big oil companies are out to get me...".

P.T. Barnum was right - there's one born every minute ;LOL