exhaust flame thrower

Do a search for a SPDT momentary contact rocker switch with a 15,000 volt rating.

you'd need a switch that can switch the thousands of volts that go to the spark plug. you could possibly use an autombile disttributor.

you'd need to attach a lever to the input shaft to to turn it sufficiently to switch to the other plug.

Are you looking for a bloody great backfire from the exhaust pipe or do you really want a flame thrower?

--Funny you should mention this. Last weekend, I think it was on Spike TV on one of the truck shows they showed how to do this. You might snif around over there. I'm planning something similar for an art car project. Another place to ask would be over at tribe.net in one of the pyro or art car tribes.

It's doable, BUT!

Yes, there are momentary rocker switches, but you wouldn't want SPDT, because then your motor wouldn't fire.

But the real problem is switching the 15-25KV spark voltage. The spark would happen in the switch. What you really need is another coil, and a free-running sparker, that you energize with your rocker switch.

If you haven't been an electronics nut for a year or more, then it'll be cheaper to buy one, if you can get one for a hundred bucks.

Good Luck! Rich

I sit next door to a performance shop, and if OP thinks he can do this for less than $100.00, he's in dreamland.

Cheers! Rich

Thats exactly the show I saw that set me on this path. I checked out the kits he was talking about, there $100 daollars. That sounds like way too much money just for a kit to divert electricity from an engine coil to rear coils. There maust have been some sort of driver involved with the kit, but still, it shouldn't cost that much. I saw that show just before going to a supercross event with Bubba Stewart, Ricky Carmichael, Jeremy McGrath, Chad Reed, every body. It was so cool.

Depriveing the engine of power is the only way this works. Without a spark a perfectly measured air fuel mixture is sent through the exhaust pipe to be burnt near the end of this journey. Your supposed to rev the engine up to a high rpm and press the switch. Momentum will keep the engine going long enough to get a good flame; so if you can shoot flames for about a second to keep the engine from stalling (at least for a minibike like mine, for a car you could go longer). I had a course for a couple of weeks in small engines. There electrical system works a magnet IN THE FLY WHEEL being sent past a small coil to generate the high voltage, so yes, the first spark would be lost in the switch but each spark after would light it up.

A side thought, what if youwere doing this with a v8 engine. could power be cou to just 4 cylindars and have them pump gas while the other four run the engine so you can get a continuos flame?

On a 40-year-old car with a carburator and Kettering ignition it would be duck soup.

Rig a pull-choke (maybe $4; $0 if you have an old lawnmower for parts). Add a 2nd ignition coil (maybe $10--less from a junkyard). Rig a SPST switch that cuts primary juice from the main coil and diverts it to the tailpipe coil. (The points are hooked to both coils.) Mount the 2nd coil near the tail pipe so the high-voltage lead can be short. (1 ft of used spark plug wire: $0) (Used spark plug: $0.)

If anyone not familiar with this device is interested in seeing and hearing it in action, go to this web site:

if the motor fires there's no fuel going into the exhaust.

Bye. Jasen

Yup. Someone else already mentioned rotational inertia. (Actually, you don't push in the clutch.) You want the fuel/air to get thru the engine UNBURNED.

I used to think that putting a 4-inch exhaust cap on 1.5-inch pipes from a 1.6 liter engine was the epitome of mental retardation, but at least that wasn't dangerous.

I nearly choked on my lunch seeing the photos of that miserable Honda Civic. Not satisfied with merely installing fart cans, these "gearheads" are now LIGHTING the farts.

The first time someone singes my grille, I'm ramming.

But why do you want to cut the juice to the motor coil? You want your motor to quit while you're trying to blow flames with its exhaust?

Thanks, Rich

On Wed, 11 Jan 2006 18:04:40 GMT, via , Rich Grise spake thusly:

Precisely. If the OP's mini-bike has a carburetor and an engine kill switch, he needs no mods. While riding, kill the ignition for a second or two, blip the throttle, and re-engage the ignition. Kaboom! Now of course, the reduced lifetime of the exhaust system must be considered as part of the overall cost. :-)

On Tue, 10 Jan 2006 23:30:33 GMT, via , Rich Grise spake thusly:

Yeah, you can put another coil and spark plug in the exhaust, but that will do squat. The exhaust is hot enough to ignite combustible material without a spark helper - the spark would really have little effect at all. What you need is unburned fuel in the exhaust.

Probably (I'm guessing here) the flame-thrower show mods are a fuel sender to a combustion chamber attached to the exhaust. Separate fuel lines, separate coil, separate fuel injection system. Hunnert bucks, yeah, that oughtta do it! :-)

On Wed, 11 Jan 2006 11:10:47 -0600, via , cbm5 spake thusly:

Ramming is soooo immature. Sue the bastards.

I've seen these - right next door, there's a "performance shop", and I occasionally see this very thing on some show car or another.

I think "a hunnert bucks" will get you about 1/8 of the system or so. ;-)

Thanks, Rich