Thread: home made flame thrower

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Thanks for the reply PackRat. I used a universal 12v coil that I mounted under my springer seat with a chrome cover/bracket. I wired the + to a momentary switch and then to the battery, and the - to the spark unit that triggers the rear coil. When I push the button it reduces the spark for the rear cylinder also so that helps put more gas in the exhaust. I got some plug wire that goes to the plug in the front pipe, and then I spliced into it there and ran it back to the rear pipe. The plugs I used were for a chain saw/weed eater and are only 1 7/8" total length. Pretty simple setup, but it works. I've been running cheap ways to do propane through my head and I may tackle that one day soon. Tough to find places to hide the bottle and valve. I could use a solenoid valve, but they are very expensive and I don't got the bread for that. Thought about kiping some hoses from a gas grill and using one of the valves from it, but it'd be tough to find a place to hide/mount it that would be accessible while riding. Any ideas for valves? I don't know how much pressure some copper tubing with a small ball valve could take?

Less money = more fun, if you are careful not to cheap on the dangerous stuff. I have flamethrowers on my 49 Chevy 1 1/2 ton wrecker, also. I can get about 2 feet of fire out each 4" stack, from a split header 250 6-killer, without adding fuel downstream, and the choke pulled about 1/4 out. Call me a liar, if you want, but just come to OZ and I'll prove it. I used an old distributor, RG58 coax, and some jumpers to crossfire the cap. Run off the belt drive and works great, as long as you take the belt off before heading out of town.
I have been working on adding fuel myself. I was considering NOS fuel solenoids, and acetylene backfire checks, with a jet orifice in the pipe, or cold start soleniods mounted in the pipe itself. I haven't found an insulator for the in-pipe injector, yet. I have turned the pipes cherry several times, and would rather not have a bomb go off a foot from my head.
I just now had a thought. What about direct inject diesel injectors? I'm headed to the diesel shop, to check it out. Catch Y'all later.

I was also considering NOS solenoids, but they are not cheap, like the industrial type solenoid valves. Let me know how the diesel injectors go. I know that there are kits sold to add propane injection for more power on diesel motors, maybe some of those kit manufacturers would have parts to use. My pipes never get hot enough to ignite propane like that I don't think. How is an acetylene check valve constructed?

No go on the diesel injectors. Pressure runs way higher than I expected, and Stroker injectors used 115V DC, also. Yes, 115V.
I saw some used NOS soleniods at the Sunflower Swap Meet, in Wichita, that were reasonable. I didn't think about using them, until later.
I can't remember the actual stucture of the backfire valves. What it does, is protect the hoses and bottles if the torch flame is forced back into the torch head(backfire).
Another thought, which just came to mind, is a fuel shutoff solenoid, from an add-on propane kit, like was used on gasoline engines.
As for your pipes getting hot, hope you don't use your flamethrower like I use mine. Last year at Rod Run, I lit a cigar off my stack. I need to move the plugs closer to the end of the pipe. I had to stop & cool off twice.
Anybody on the board been to the Ord, NE Rod Run flamethrowing contest out at the K-Line?

Would you really need check valves with the propane? Engineers correct me if I'm wrong, but won't it only ignite in the presence of oxygen? I need to go check out my gas grill and see how it's set up. I would think if you had maybe a 1/16" jet for the propane to shoot out of and kept it flowing until AFTER you shut off the spark, that it would not backfire into your propane lines. With a small jet you wouldn't be letting oxygen into the line. I'd like to see how the people who have done propane injection have their's set up.

this is the link you want for flame thrower advice....
1979 corvette - Flamethrower Exhaust?????
i have posted pics of our setups for gas or propane fuelled systems...
you do need to insulate the hose feeding the fuel supply.. either by using a long length of pipe to help dissipate the heat or by using decent heat resistant hoses (V expensive)...by using the solenoid type shutoff valves you will not have to rig up a set of injectors or what have you... the fuel will 'inject' and vaporize off the fuel pump pressure as it 'backs up against a small aperture in the tube inserted into the tailpipe.. i use 1mm bore stainless tube peened down to .5mm creates good pressure in the fuel sys and therefore mists the fuel...instead of dribbling gas into the exhaust... petroleum mist = easier to ignite.. 12v fuel shutoff valves like those are not expensive, and they ar also useable when you upgrade to propane as they are gas tight too....