Propane for Rudy’s Pioneer

[a41capt]

After completing my Webster build, I have started my next engine, Rudy’s Pioneer. As a 2-stroke, I noticed that his design does not provide for a top-end oiling system, relying instead on a traditional 2-stroke gas/oil mix for fuel-lubrication. I’d like to build the engine to run on propane, and was wondering if anyone has tried this mod. If so, what carburetor changes did you make, and will a small cylinder mounted oiler provide the necessary oiling to the ringless piston?

Another issue I’ve noticed in the plans is the lack of bearings for the main and big end. Steel on aluminum?

Thanks in advance, I’ve just been cutting out the stock for some of the components and wanted to get ahead of any changes that one of you may have found helpful in your build.

John W

 

[Sprocket]

I didn't like the idea of aluminum on steel either, so on the "Gearless" I built, I added a split bronze bushing. It's thin, but it fit in.

I'm also planning propane on the Nash I'm working on, and it seems the biggest difference is a demand valve for the propane. I understand the needle valve has to be opened more than for liquid fuel, and the demand valve allows gas to flow only on the intake stroke. I got plans and parts for the demand valve from Jerry Howell Gas Engine Propane Demand Valve but I haven't built it yet. I will have some splash oiling, so don't know about the piston oiler idea, but it can't hurt.
Hope that helps.
Doug

 

[a41capt]

Doug, This is the demand valve I made from plans posted in the FAME group:

 

[Sprocket]

Kind of looks like the plans, diaphragm and needle valve inside, small engine carb parts if I remember.
You're way ahead on that front. Have you run anything on it?
Doug

 

[a41capt]

I didn't like the idea of aluminum on steel either, so on the "Gearless" I built, I added a split bronze bushing. It's thin, but it fit in.
View attachment 131748 View attachment 131749
I'm also planning propane on the Nash I'm working on, and it seems the biggest difference is a demand valve for the propane. I understand the needle valve has to be opened more than for liquid fuel, and the demand valve allows gas to flow only on the intake stroke. I got plans and parts for the demand valve from Jerry Howell Gas Engine Propane Demand Valve but I haven't built it yet. I will have some splash oiling, so don't know about the piston oiler idea, but it can't hurt.
Hope that helps.
Doug

Here’s a pic of the plans I downloaded for a demand valve from the F.A.M.E. group:

 

[a41capt]

Kind of looks like the plans, diaphragm and needle valve inside, small engine carb parts if I remember.
You're way ahead on that front. Have you run anything on it?
Doug

Tried it on my Webster and it drew propane if I covered the inlet on the carb. I didn’t screw with it enough to make it run, just wanted to see if the valve would open.

John W

 

[Harglo]

After completing my Webster build, I have started my next engine, Rudy’s Pioneer. As a 2-stroke, I noticed that his design does not provide for a top-end oiling system, relying instead on a traditional 2-stroke gas/oil mix for fuel-lubrication. I’d like to build the engine to run on propane, and was wondering if anyone has tried this mod. If so, what carburetor changes did you make, and will a small cylinder mounted oiler provide the necessary oiling to the ringless piston?

Another issue I’ve noticed in the plans is the lack of bearings for the main and big end. Steel on aluminum?

Thanks in advance, I’ve just been cutting out the stock for some of the components and wanted to get ahead of any changes that one of you may have found helpful in your build.

John W

John
I use propane to run all my engines. Chain saw carbs diaphragm works should you wish to reduce the over all size. I use a weber "go any Where" regulator which has an out put of about .5 to ? output. Takes some fabrication to attach to the the one pound throw away cly's. Occasionally have had some tiny debris get under the needle an seat due to no cleaning of the clys after some machining for the threaded neck. Made up a diaphragm manifold to run 3-4 engines at same time with propane proof very small quick disconnects. Use 1/8" tubing have no idea if that is an ok size Id.

Harvey

 

[a41capt]

John
I use propane to run all my engines. Chain saw carbs diaphragm works should you wish to reduce the over all size. I use a weber "go any Where" regulator which has an out put of about .5 to ? output. Takes some fabrication to attach to the the one pound throw away cly's. Occasionally have had some tiny debris get under the needle an seat due to no cleaning of the clys after some machining for the threaded neck. Made up a diaphragm manifold to run 3-4 engines at same time with propane proof very small quick disconnects. Use 1/8" tubing have no idea if that is an ok size Id.

Harvey

Thanks Harvey, I will probably do just as you have with my Webster and the Pioneer once it’s finished. While I know propane itself can be a dangerous flammable gas (I am a retired firefighter and Hazardous Materials Specialist), the thought of a gasoline spill and fire while displaying at a club event worries me even more. I may even go so far as to building the demand valves with threaded connectors into the bases of the engines in order to “clean-up” the tabletop during displays. Therefore, any info you can forward regarding miniaturization with smaller diaphragms/needles would be greatly appreciated.

On another subject, my Webster runs a Traxxas RC carb. After the wrestling match getting it to run on Coleman fuel, do you have any words of wisdom to impart regarding the conversion to propane?

Thanks in advance,
John W

 

[deverett]

I remember somewhere, some time ago that a trick to check the throat size required when using propane was to cover the air inlet of the carb with something like masking tape. Pierce the tape and enlarge the hole at each starting attempt until the engine runs. That last hole in the tape will give you the throat diameter required.
Maybe someone who has tried this will be able to confirm what I remember and/or modify as necessary.

Dave
The Emerald Isle

 

[a41capt]

I remember somewhere, some time ago that a trick to check the throat size required when using propane was to cover the air inlet of the carb with something like masking tape. Pierce the tape and enlarge the hole at each starting attempt until the engine runs. That last hole in the tape will give you the throat diameter required.
Maybe someone who has tried this will be able to confirm what I remember and/or modify as necessary.

Dave
The Emerald Isle

Thanks Dave, next time I get a minute to try it out, I’ll take a piece of tape to it!

BTW, my maternal great grandparents originated form somewhere near your location in West Cork. My IRA great grandfather escaped just a bit ahead of the British army enroute to America. Different times for sure!

John W

 

[Harglo]

Thanks Harvey, I will probably do just as you have with my Webster and the Pioneer once it’s finished. While I know propane itself can be a dangerous flammable gas (I am a retired firefighter and Hazardous Materials Specialist), the thought of a gasoline spill and fire while displaying at a club event worries me even more. I may even go so far as to building the demand valves with threaded connectors into the bases of the engines in order to “clean-up” the tabletop during displays. Therefore, any info you can forward regarding miniaturization with smaller diaphragms/needles would be greatly appreciated.

On another subject, my Webster runs a Traxxas RC carb. After the wrestling match getting it to run on Coleman fuel, do you have any words of wisdom to impart regarding the conversion to propane?

Thanks in advance,
John W

USP plastics has propane approved small quick disconnects along with apporved tubing. Photo of my propane station. Are you in the US?

 

[a41capt]

USP plastics has propane approved small quick disconnects along with apporved tubing. Photo of my propane station. Are you in the US?

Camp Verde, AZ, USA!

Really nice setup Harvey. I’m wondering if there’s a compatible plastic that I could have my son 3D print for me. I’ll have to do some research!

John W

 

[Harglo]

Camp Verde, AZ, USA!

Really nice setup Harvey. I’m wondering if there’s a compatible plastic that I could have my son 3D print for me. I’ll have to do some research!

John W

 

[Harglo]

I make my own carbs an have trouble with every one. The air in take is supper critical tinyest amount of air. I can't change the speed on my engines the governors fix that that's why would like to see drawings of other carbs. Im making JE Howells Twin V an have much trouble with the carb/s for it haven't gotten it to run. Can do ea cly but not both the timing is strange as crank pin serves both rods. Wish bone type. Those quick disconnects have o ring shut offs
Harvey

 

[a41capt]

I make my own carbs an have trouble with every one. The air in take is supper critical tinyest amount of air. I can't change the speed on my engines the governors fix that that's why would like to see drawings of other carbs. Im making JE Howells Twin V an have much trouble with the carb/s for it haven't gotten it to run. Can do ea cly but not both the timing is strange as crank pin serves both rods. Wish bone type. Those quick disconnects have o ring shut offs
Harvey

I was thinking of having my son 3d print the demand valve blocks to fit a diaphragm kit. I’d like to do away with the huge amounts of swarf removed from blocks of aluminum if at all possible. The quick connects look like a great idea, so I’ll probably incorporate those into any of my plans.

As for the Howell V-Twin, isn’t that a single carb manifold with the usual Harley 90 degree crank timing? Take a look at the Traxxas RC carb as a viable option to your problem. It is a barrel throttled type carb with low speed and high speed needle adjustment. Like me, you may have to build a restrictor to get the vacuum draw to open a propane demand valve, but the carbs are well known and described in several builds on this forum.

 

[Harglo]

I was thinking of having my son 3d print the demand valve blocks to fit a diaphragm kit. I’d like to do away with the huge amounts of swarf removed from blocks of aluminum if at all possible. The quick connects look like a great idea, so I’ll probably incorporate those into any of my plans.

As for the Howell V-Twin, isn’t that a single carb manifold with the usual Harley 90 degree crank timing? Take a look at the Traxxas RC carb as a viable option to your problem. It is a barrel throttled type carb with low speed and high speed needle adjustment. Like me, you may have to build a restrictor to get the vacuum draw to open a propane demand valve, but the carbs are well known and described in several builds on this forum.

Thanks will check out the Traxxas. I suspect some fluid mechanics comes in to play with the size an lenghts of tubing when using propane but have no knowledge of that I ignore it. As far as safety I file colemen or gas is much more of a problem esp for transporting the containers etc. Propane hook ups are just so user friendly vs spilling with fueling a tank.
Harvey

 

[awake]

According to this site, PETG is stable with propane:

http://kmac-plastics.net/data/chemical/petg-chemical.htm
PETG requires a bit hotter temperatures than PLA, and ideally should be used with an all-metal hot end. Otherwise, it is an easy filament to use for printing. I don't know how it would stand up to pressure, but if you keep it low ... probably fine ... ?

 

[a41capt]

According to this site, PETG is stable with propane:

http://kmac-plastics.net/data/chemical/petg-chemical.htm
PETG requires a bit hotter temperatures than PLA, and ideally should be used with an all-metal hot end. Otherwise, it is an easy filament to use for printing. I don't know how it would stand up to pressure, but if you keep it low ... probably fine ... ?

Thanks Andy, my son is going to try a special resin he has for his led printer so we will see how that turns out. He’s having some trouble with the 3d modeling as he doesn’t usually work in imperial measurements. He also doesn’t do threaded fittings, so I’m having him size the holes for the minor diameters and I’ll tap whatever he gets me. I’ll let everyone on the thread know how it works out, perhaps someone else will be interested in using this technology for a cheaper alternative.

John W

 

[a41capt]

Thanks will check out the Traxxas. I suspect some fluid mechanics comes in to play with the size an lenghts of tubing when using propane but have no knowledge of that I ignore it. As far as safety I file colemen or gas is much more of a problem esp for transporting the containers etc. Propane hook ups are just so user friendly vs spilling with fueling a tank.
Harvey

I agree with the thoughts regarding flammable liquid spills Harvey, especially in an indoor show! As we say in HazMat response, “The flammable range WILL be present somewhere…”

John W

 

[awake]

Thanks Andy, my son is going to try a special resin he has for his led printer so we will see how that turns out. He’s having some trouble with the 3d modeling as he doesn’t usually work in imperial measurements. He also doesn’t do threaded fittings, so I’m having him size the holes for the minor diameters and I’ll tap whatever he gets me. I’ll let everyone on the thread know how it works out, perhaps someone else will be interested in using this technology for a cheaper alternative.

John W

Ah, a resin printer. I have never used one, so tend to think automatically of filament printing ... but I have a resin printer coming my way for Christmas, so I am looking forward to learning more about that process.