So--I have a question for you guys who have been around longer than I've had the privilege of existing. We all know the purpose of the spark plug and based on the decades of their existence--spark plugs haven't much changed in appearance or function.. why? Are they perfect as originally engineered and mildly refined?? Well-here's the purpose I ask the question. I stumbled across these old Surface Gap Fire Injector spark plugs today and grabbed them as there is a full set of 8, unused and still wrapped in their wax paper. They were either sold or manufactured by International Automotive Sales Corp and made in the U.S.A., Connecticut to be exact. My question is--why didn't they work?? Did anyone use them-or does anyone still use them?? They look like a novel idea, however I don't know squat about true engineering. Anyone willing to entertain this topic?? Overall--were they a failure?? What happened to them??
Good review here from a 1968 Popular Mechanics article; Base test (stock car): 10.755 mpg, acceleration 25-70 mph - 8.4 seconds With "fire injectors": 10.6 mpg, acceleration 25-70 mph - 8.55 seconds Link: http://people.ucalgary.ca/~csimpson/Articles/GMiser.html The article states they were distributed by JC Whitney...
That article was interesting. Would be interesting to determine what these plugs were intended for--would be cool to try them out on today's fuels..
I never used those, but the major plug manufacturers (I know Champion did) made "surface gap" plugs for use in outboard motors. I had used them in a 50 HP Johnson. (Viewed end-on, they looked like a metal and porcelain target.) In the 90's, I built a '36 3-window with a 276" flathead with among other things, Offenhauser heads, an Isky cam, and an MSD ignition system. I had problems getting plugs to work in it. If I ran 3/4" reach plugs, the valves would close up the gap in a couple of cylinders. If I ran shorter plugs, they would be shrouded in the spark plug holes and expose the sharp threads. I remembered the "surface gap" plugs from my boating days, and tried a set (they were all 3/4" reach) in the flathead. They worked great; car ran super and I never had a problem with them fouling. In truth, I would have to say the reason they worked so well is because of the MSD ignition; that thing made a spark that would jump a 1/2" gap. I am building another flathead, and will try them again. The alternative is to go with standard 3/4" reach plugs and do some costly machine work on the heads and/or pistons. Another reason they probably worked as well as they did is that they were made to higher standards by an American company. Who know where the ones you show (or the J. C. Whitney ones) came from. Just my 2 cents.
I remember my uncle sold them as a sideline in the 1950's,but I believe the ones he sold were called SA Fire Injectors.The company used to advertise in the back of such magazines as Popular Mechanix and the like extolling the virtues of selling them and making tons of money. He sold those and an additive for batteries that was supposed to extend their life tremendously.As I recall none of these,"wonder" products sold very well.
I saw my neighbor working on his 65 352. He was throwing the spark plugs into a vacant lot, when questioning him he showed me the Fire Injector box, "throw your old spark plugs away?". Next week I saw him in the field looking for his old plugs...
for one cannot adjust the gap once it starts to wear and might put the fire in the wrong spot and cause a misfire . we used the outboard plugs as they were real cold and with a 2 stroke you do not want any source of ignition before that port closes as it does bad things to crankcases or carbs. I would shelve them as a novality item
"Surface fire" plugs are in use today in super high performance applications. The absence of the ground strap allows for more squish without risk of the piston bumping the strap and also it eliminates one more sharp angled item in the combustion chamber to create a heat spot that would lead to detonation on some more extreme engine combos like massive amounts of nitrous (which in nitrous leads to a blow torch like situation that cuts the head clean off of your valves depending on where the ground strap is pointing). It is used pretty extensively on factory motorcycle road race teams and in 150+ hp shot drag and land speed racing bikes, including my own 150 wet shot lsr bike. Downfalls to the plug, extremely expensive if you require a resistor plug, NGK resistor surface fire plugs retail for 80ish dollars each but can be found for 40 dollars or so each, and they are VERY easily fouled so if your air fuel mixture is anywhere near not perfect you better carry around a few spares, and lastly your ignition system better be as hot as the fires of hell to make a good hot spark. And what can happen with a traditional plug if your tuneup is a little on the more aggressive side...
Good to see there is a real use for the technology. In the 1970's the OP's type had a full page add in the JC Whitney catalog. Even as a kid I knew that something they hyped like that -and not sold elsewhere - had to be hokum.
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Yep, stuff like that have been marketed over the decades, by almost every company, as the latest and greatest.
1963 Falcon Sprint experience showed Fire Injectors to be a significant improvement over stock, when tuned in my driveway; the original plugs weren't re-installed for post-tune comparison. The Ford dealership used the tune-up specs for the L6 engine instead of the hi-po 260 V8, and it would barely run; I complained to the service manager, who went with me for a ride: Under maximum acceleration through the nearest intersection (green light, no cross traffic), the car just touched 55 mph; he said, "It's just a Falcon: it isn't a high-performance car." I took it home and did my own tune-up (with Fire Injectors) and took it back less than an hour later, and got the service manager to ride with me again; we crossed the same intersection at just over 100 mph. When I bought the car, it hit close to 100 mph when I test-drove it along the same route; there's a chance that the balance and weight of the car, together with the atmospheric conditions and changes in the traction available on the road could make that much difference, but the car definitely "felt" faster with the Fire Injectors. Many sanctioning bodies have specifically outlawed Fire Injectors on the claim that they offer an unfair competitive advantage when contrasted against other spark plug types; curiously, major sanctioning bodies don't seem bothered by the hypocritical policy of requiring a particular brand of tires (NASCAR requires Goodyear tires), so just because you don't see racers using them doesn't mean they're crap. The service department put my Falcon Sprint on an oscilloscope-type device that allowed the technician to observe the sparks at each plug; the pulses were identical. The tech said he'd never seen all the pulses exactly the same; the only thing I'd changed (other than the dwell and advance) was the plugs.
For what its worth, I have never had a surface gap plug foul on an outboard motor like regular plugs do. If you spend a lot of time idling with a two stroke like when trolling, they tend to foul the plugs. Mine uses Champion L78V.
In the early 70's the 36' Cigarette offshore race boats started to be a big deal, and most of them used 2 1/2 stroked BBC for power Mercruiser made a special ' Thundervolt 'electronic ignition for those boats as they had to idle out for long distance's, and not foul any spark plugs that were the surface gap style and worked very well The unit was a very high out put for the time and was a complete diecast box that bolted to the back of the engine block The plugs they used were not projected like you show but flat across even with the end of the plug cartrage And you did not want to get zapped by that beauty cause it would knock you on your butt DND
I remember a book from the 1980's called "The Doctor's Step-By-Step Guide To Optimizing Your Ignition"...I forget who wrote it, but he also sold a module that was supposed to increase performance and fuel mileage. I tried one on a Pontiac 455 I had at the time, and it didn't do much of anything. The MSD 6A I installed later on really woke it up, though.
Take a look at the aircraft spark plugs from WWII : the surface gap was intended to keep the engines running during wartime conditions by having a "correct gap" available at all times(unlike a conventional spark plug that has only one "gap" available, & when it is no longer "correct" that cylinder stops working properly, if at all.)
My FIL was a refugee in Germany in 1945 and somehow owned a motorcycle. The spark plug was shot and he needed a new one.. nothing at all was available (or he didn't have any money). However, there was an old Luftwaffe base near his home so he went over and convinced the US MP to let him go through the junked German aircraft. He pulled sparkplugs and to his surprise, all of the plugs were "surface gap" plus. He eventually found one that would fit his motorcycle and put it in. He was amazed at the vast improvement in performance. He used "Fire Injectors" in his '57 Ford, I used them in my '59 Hillman and still have a set!
My 1970 O/T Kawasaki two stroke Mach 3 motorcycle had CD ignition and surface gap plugs, never fouled a plug. And we know how they ran.
Old stuff for 2-strokes and carb engines , some aviation apps. And rotary's also. If they are relevant today, all the OEM's would be using them instead of platinum for the last 20 years. BMW had version in the 90's, no more.
I think the book you are referring to was part of the Jacobs ignition marketing by Jacobs Electronics.