Propane conversion

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Dan

Staff
May 25, 2008
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Moosylvania
alls that would be needed is a diaphragm? the needle in the carb and existing throttle would work? Run gas in the same as liquid. I am missing some thing here, eh?

How would you match a diaphragm size to carb bowl size or CC of engine?

Dang Pops, am sure I am lost. Can it be that simple? This is really getting to be a fun thought. Thanks again

Want to try this lunacy with this engine; Harbor Freight Tools - Quality Tools at the Lowest Prices
 

POPS

Member
Sep 8, 2008
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Vancouver Island BC .Canada
Dan...Your very welcome. Thats why we are all here, To help and learn. I've got a problem doing links. Type in Honda generator propane conversion. The first couple of links that come up have lots of info. What you have to do is size the mixer to CC/horsepower. Check out the link...POPSscratg
 

POPS

Member
Sep 8, 2008
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Vancouver Island BC .Canada
IMPCO Technologies
Hope this works.
Lots of info...POPS
There you go Dan...Read Read Read
Click on products on the left of the page then scroll to the bottem of the page and download the catalog. Everything you wanted or need to know!!!!...POPS
 
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eDJ

Member
Jul 8, 2008
530
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18
Wayne National Forest
This thread just keeps getting more interesting........Thanks Pop's & tyrslider for your input.

My Propane supplier (as my home uses Propane) has a 1 1/2 ton Ford delivery truck for
delivering bottles of gas. The truck is converted to using propane but with the flip of a swithch
can go back to running gasoline. The fellow who drives it and delivers showed me under the hood and there are two mixers attached to the lid of the air cleaner. (centered just above the two venturies
of the carb) The truck runs a 400M V8 engine and he says it runs smoothe as silk on the propane
and the double throw swithch shuts off the electric fuel pump mounted at the fuel tank and when
in the propane supply position the solenoid is energized to open the gas supply valve to the metering
valve diaphram which senses the low pressure at the mixers to allow the propane to
flow into the opening of the carb thru the mixers. Just that simple.

The first time I saw a photo of Harold Bate in the UK, the photo was taken during WW2 in his
converted Austin taxi (I believe it was an Austin) where he had a discarded barrage balloon
mounted to the roof between a couple sheets of plywood. By the use of some ingenious slip
knots and rope lashings he could pull the end of the rope thru the drivers window to maintain pressure on the balloon (as he had no metering system then) which had been filled with methane gas at his home.

The question Pop's brings up regarding the crank case igniting and becoming a bomb could be overcome by building a safety "Poppet" valve into the bottom or side of the case. If on the side
a diverter shield would probably be necessary so you don't get a flash burn on your leg. THINK SAFETY !

As far as a timing advance mechanism in these HT motors.......I'm not so sure there is any.
I'm no stranger to using a SUN distributor scope to make adjustments when swapping distributors or swapping springs on weights in GM distributors to plot different advance curves. But for what these little HT's are.....I think we've really pushed the envelope with em here.

What I'm wondering now is if the oil could be mixed with some gasoline so it would flow much easier
and metered into the carb venturi with a adjustment needle (perhaps 2..one for idle and one for higher rpm ranges like the carb needles on a string trimmer) In this way an oil pump wouldn't be necessary and the tank could gravity feed the oil supply adaquetly. I'm guessing by observing the
exhaust for smoke one could adjust the needles and after running it a bit one could read the plug.

Just some thoughts.
 

Ev in CT

New Member
Feb 14, 2010
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CT
Dan Hi newbie here.. I think I have figured out what is needed to make a propane powered MB. Contact me if you want. I'm in Litchfield County. Evan
 

Dan

Staff
May 25, 2008
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Hey Evan, great to meet ya and welcome!

Very cool! Will PM you. Working on a harbor freight build. Would be an awesome engine to convert. I had forgotten about this. (lol, a tree hugging, bunny loving green MB or THBLGMB)((say that 3 times fast))

Side note, me and a few folks get together for rides here an' there. Your invited to join us. Like most MBers, these guys are half a bubble off plumb to the good and a blast to hang out with. Also host a rally sort of thing in late may. Gonna be in Wethersfield this year. My wife is an awesome cook. Last yr we forgot to bring a spatchula/burger flipper thing, so we used china girl chain tensioner.

Only the finest cookware will do for our events, snork
 

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Ev in CT

New Member
Feb 14, 2010
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CT
great, I know guy over in Simsbury that I was just talking to on Friday that is converting the towns lawn mowers to propane it should be a similar set up for any small 4-cycle. He will share his knowledge on that. We get get together any time. Evan
 

Dan

Staff
May 25, 2008
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Moosylvania
Just reread this whole thread. Wow! Ya get on new stuff and projects and just let stuff go. Thanks Evan! One of the early posters is now my biz partner. (Ironically, named Evan also)

Just got off the phone with him saying we gotta do this! LOL, after re-reading this, saw we had spoke about it 2 yrs b4 starting out. 2 funny.

Owe ya a cold one EV, ty for reviving this
 

Ev in CT

New Member
Feb 14, 2010
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CT
all set with what's needed to make a propane conversion. I just need to pick a 4 stroke and transmission. Any suggestions. Dan send me a pm if ya want to get together, Evan
 

Prasinos

Member
Dec 1, 2008
261
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California
Jeeze i didnt realize there were so many Nutmeggers in here. I wanted to do this with a 2 stroke myself but i was told making a oil injection system would probably cost more than the engine....

But as far as 4 strokes, i feel like this would be simple. Im thinking of the mythbusters episode where they ran a carbeurated car just by puting a hose of hydrogen near the carb. If you just wanted to try out the theory you could hook up a little coleman tank and just turn it on a little at a time untill wot worked. If that worked well you could figure out some sort of needle valve setup.

I would think the intake charge would be much denser if you mounted the tank upside down, maybe more moper than gasoline?
 

Elmo

New Member
Sep 3, 2009
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Mississippi
I have some experience driving propane/gasoline dual fuel vehicles. My personal observation is that propane in a vehicle setup to run gasoline produces about 1/4 less power based on seat of the pants method and gets less fuel mileage. That said my FIL hade a 1/2 ton farm pickup that was setup to run both and at 225,000 miles the carb caught fire and melted & went down the manifold(350 chevy). We pulled the heads to check whether any got into the combustion chamber. The pistons, valves, and combustion chamber looked like it was brand new. He put another carb on and sold the truck with 300,000+ miles and it still ran well. the oil didn't get dirty like a gasoline engine either.
Best of luck I hope you are successful in this project.
 

Ev in CT

New Member
Feb 14, 2010
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CT
to get an idea on conversion you just need to look at small 5kw propane generator conversions. Ev
 

discontinuuity

New Member
May 24, 2010
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Colorado, USA
I tried this on my lawnmower awhile ago. The carb was clogged up and I didn't want to tear it apart to clean out the jet again. So I found about 1 foot of vinyl tubing and put one end on a blowtorch, and the other into a hole I drilled into the intake box. It started right up on the first pull and ran for about 15 minutes at a time before the propane bottle iced up and the flow petered out.

This was a roughly 100cc engine, so I imagine a 50cc bike engine would run better without icing up the bottle. Although one go-kart mechanic I talked to said that propane burns hotter and can overheat your engine, so watch out.
 

Mind_Reader7

New Member
May 1, 2010
392
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Northam, Western Australia.
I've worked with fork trucks which run Propane and they get much longer service lives than those running gasoline. If you have to pull one down you'll be amazed at how clean they are inside.
We do this at work. The engine has both a fuel tank and propane tank. There is NEVER any fuel in it. While honestly you would be better using fiel because you can stop at any servo and get it if you're going long distances.
 

camlifter

Active Member
May 4, 2009
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acme labs marion ohio
i/m a little sceptical of how well this would work, we use propane tow motors at work and i once drove a converted truck for a company i worked for. all the conversions i've used were for water cooled engines, the hot water from the cooling system converts the liquid propane to vapor to be used by the engine. if you used vapor, like in a bbq tank the tank would need to be prety big not to ice up.