propane tractors?

I've always wondered about the older propane tractors. How does one fill the tank on it. You must have to have a big tank and hoses/ regulaters to refill. Is that stuff expensive to purchase. I've heard that propane engines and really really clean inside after tons of hours of work, compared to a gas engine. On the tractors whats different, the carb and manifold and gas tank? Is power a little more with propane?

There are some positive aspects of LPG power and the oil does stay clean or clear for a long time, same with the internal engine components, at least from what I can see of mine.

Mine uses an Impco model J vaporizer, not sure what carb is on it, and a 30 lb tank, like commonly seen on a forklift. Easy to change a tank out, but I pay way too much for refills, thats the only thing I'm not liking about it, $25 flat rate to refill, regardless if it's empty so if you want to top one off, it can be costly. My heating oil supplier just opened up a nice size LPG division, now time to see what my options are, thinking a few extra tanks will be it, right now it's $3.57/gallon at Agway, topped on off Sun. it worked out to $5.35 /gallon, might have to ask them about a gallon price, they probably won't do it though. When I first got this tractor, LPG was cheap, like $12 per 30 lb tank.

Cold weather starting can be an issue, and I do not know all the details, except the cold can keep the LPG from vaporizing, so if I leave it outside, I have to tarp it and use one of those LPG Ready Glo 44,000 btu heaters under it and a tarp, 15 min. of that and she will fire right up, then the coolant line from the engine, will supply heat to the vaporizer, just that initial start, though sometimes it has suprised me, 20 deg F it has started without heat.

The tractors with the mounted tank, seem to have some means to start on vapor and or you can fool with or adjust for cold weather starts, I don't know jack about those, that and the nurse tank and refill set up, kind wish I could refill my own, but maybe I'll find a better deal, the current one is a rip off.

PS, may sound odd, but this tractor has not had an oil change since Sept. '04, oil is clear, 15W- Rotella, though I'm not sure if that is pushing it, I will change it before winter and do so more often, at a glance, seems like those oil change intervals can definitely be extended, not sure what the norm is for LPG and what contaminants or breakdown of the oil occurs etc.

Power is a little less. I do not have a tractor but a combine. I was able to acquire a Liquid LP pump to fuel my machine. If you understand a little chemistry you can fuel a LP machine. Most residential tanks have a liquid tap. You need a special fitting for this tap, a couple of valve rated for liquid LP, a liquid LP rated hose and a filler fitting. No regulator needed. Most connect the fill hose and open the liquid level test valve and vent LP vapor until Liquid LP appears at the valve. You MUST remember that LP vapor is HEAVIER than air and will pool in low areas if there is no or little wind. You can also run the engine of the machine from the vapor outlet of the fuel tank. This causes the pressure in the tank to drop letting the tank you are filling from fill the tractors tank. I did this this weekend at an engine show to fill the LP tank on a Allis-Chalmers model L power-unit. I was filling the power units tank from a fork-lift tank.

Kent

I forgot to mention that in cold weather, when using any LP fuel engine you should shutdown the engine by shutting the fuel off. Do not forget to shutoff the ignition. The next time you start it, turn on the VAPOR valve, start the engine and run on vapor until you have heat in the cooling system. Then turn on the liquid valve and shut off the vapor valve. Then shut off the fuel to shut down. In cold weather ALWAYS start on vapor or the Regulator/Vaporizer may freeze up before you have heat in the engine. I did not have to worry about this on my combine because I ran it in the summer.

Kent

My dad bought our first propane tractor in the mid 1960s, a Minneapolis Moline G 705 rated at around 100 horsepower.

We didn't use propane to heat with so had to purchase a propane nurse tank. We had a 500 gallon tank and mounted it on a trailer.

No regulator is used for filling. The nurse tank must have a "liquid leg" so that liquid can be withdrawn from the tank.

For filling without a pump the liquid line is hooked to the tractor valve to allow liquid flow then vapor is bled from the tractor tank which allows liquid inflow. To a point the faster the vapor is bled off the quicker the tank will fill.

We had a hose on the vapor "bleeder" and blew the dust off of the tractor as we bled the vapor off.

It helps to understand propane if you will liken it to boiling water and steam. Propane vapor is simply the result of boiling liquid. The boiling point for propane is something like -42 degrees F.
Any temperature above that and the propane will be boiling.

If a tractor is properly tuned and is started on vapor cold weather starting is not a problem. With LP there is no engine stumble as with a gas engine, once going it runs smoothly.

Going back to the water/steam example, if you remove lid from a pan and let the steam escape the boiling action slows. Same with propane if you remove the vapor too quickly the boiling slows. Thus propane tractor run on liquid LP. The liquid is run through a vaporizer heated by engine coolant. The vaporizer is also a regulator supplying the engine with the correct amount of fuel.

And yes, an LP carb is different from a gas carb.

Some folk install dual fuel set ups on vehicle engines. Tank, vaporizer as before, but instead of a special carb the LP is controlled by a unit that fits over the conventional carb and a Bowden wire switches between the two while electric solenoids turn on and off the fuel of choice. Not an ideal set up but it does work.

One distinct advantage of propane years ago was that it was such a cheap fuel. Modern uses hadn't been implemented yet and it was often just flared off as a waste gas. Many of my dad's old fuel tickets show purchases as low as 4 cents per gallon for the LP. I, myself, have bought much under 20 cents per gallon.

Since the LP vapor is dry it doesn't wash down the cylinder walls like gasoline, hence the longer engine life and cleaner engine.

No need to guess--I'm a fan of LP. I wound up hauling for a local dealer for 7 years as I built up my farm.

Tanks are cheap out here in the Texas Panhandle, because almost everybody has/had LP of some form...

That is not so true now as it used to be, with most modern equipment going to diesel.

I'm 46 - and I grew up with it on the farm. I could fill the equipment by myself by the time I was in 4th grade, but Dad had also given me pretty careful instructions on what to watch out for. (not that it is hard, but you sure don't want to set a spark around the bleed off vapor!)

Our combine, both 4020 JD tractors, and all the pickups were on LP when I was a kid.

There is a local place that still does conversions on pickups, so they can run on gasoline or LP at the flick of a switch.

And yep, the engines sure run clean - especially compared to an old diesel!

And one big advantage is LP never goes bad like gasoline or diesel can, which is very handy on equipment you don't use often!


Howard

One thing to always remember around propane is to wear protective gloves and a full face shield when refueling. I worked at a place that had about 20 propane forklifts and I quite often refilled them. For some reason everybody else did not wear a face shield, but I always believed in safety.
I had a near accident when I was refueling one day. I had unhooked the hose and it was about 3 seconds afterwards when liquid propane shot out past the valve at me for a good full second. My face shield was completely frosted over. Had I not been using a shield it would have hit my eyes. I was pretty lucky that day.

Lots of helpful advise below. I will furnish a little trivia I picked up on down in La. back in the 1960's, I asked a farm manager [a white man] why they had so many LP tractors and he said this: field hands steal gasoline for their cars,they steal diesel for their stoves and they are scared to death of LP and leave it alone.so most farms use Lp tractors and equipment.Don't know what he or they did about the farms cars and trucks. This is the truth as told to me and I don't want to start a racial rigamaroe over it.I care less one way or the other.My apoligies to any one who feels slighted.JH

I just skimmed the other replies so forgive me if I repeat.

On a proper LP tractor (either complete conversion or factory) there are several things that are different. Of course the tank, carb, and convertor need to be added.

What a lot of people might miss is that you need to raise the compression somehow. Usually done with a different head but sometimes done by using different pistons.

Other thing is the manifold will be different. Reason here is the fuel is vaporized in the convertor using engine coolant. In a gas engine the heat that is needed to vaporize the fuel is added by having the exhaust and intake manifolds connected somehow to transfer some of the exhaust heat over to the intake. Now the reason why they don't just use a regular manifold is the colder the intake air is the more you can pack in the engine. More air/fuel equals more power.

As to horse power I know this is a subject of some debate but if I remember right LP tests better at Nebraska. I know the tests for tractors like my LA case LP is the highest rating of that engine, but the difference is negligible.

As for fueling there are a number of different ways to do that. Main thing you need is a tank with liquid withdrawel. I would suggest a dip tube instead of drawing off the bottom. There is a precipitate in LP that is about the consisitancy of gun grease and stinks to high heaven. Reaks havoc on convertors and carbs also. I have used a line going to the tractor tank and just venting off the vapor in the tractor. This needs to be done with some degree of caution and not a good idea in town. Last I knew hand pumps were still available and I have one I use. Not sure what they cost. Contact your local LP suppier about this setup.

When you provide pickups for the hired hands, it DOES just help keep everyone honest. We usually had 2 or 3 provided out.

No messing around with dividing up the bills at the gas station in town, or wondering where the gasoline is going, etc, etc...

They could just fill up with LP at the farm and that was the end of it...


HH

Good point about the higher compression.

I rebuilt a Chevy 350 as a dual fuel engine and upped the compression to 10.5 to 1. Sure helped the LP performance since it is a higher octane fuel.

When I sold the pickup a few years later the first thing the buyer did was remove all of the LP equipment.

He sure didn't care for the pinging he got with the lower octane of gasoline and seemed to always be tinkering with the timing in order to get away from it.

Once the engine had a higher compression I got somewhat similar fuel economy on both fuels. Before better on gasoline which is proper as it has more BTUs in a gallon.

That reminds of the one about the skydiver who jumped out of the plane and had trouble with his parachute.After both the main chute and the backup failed to open he was suprised to meet a man going straight up.He cupped his hands and shouted to him."HEY BUDDY YOU KNOW ANYTHING ABOUT A PARACHUTE?". To which the man replied "NO SIR,DO YOU KNOW ANYTHING ABOUT A GAS HEATER? Moral of the story is,It pays to know what you are dealing with.

I have had 3 LP 2 cylinder JD tractors, my opinion it's great. They can sit for a long period and the LP doesn't get nasty like gasoline. True story, my brother bought a new JD 60 in 1956, about two years ago he was having some trouble and took it into his local John Deere dealer, the mechanic working on the tractor said to my brother "boy this tractor must not have many hours on an overhaul there's not even a ridge on the cylinders" to which my brother replied "you are the first mechanic to lay a wrench on it". By the way the head had a tiny crack. (somewhat common in a high hour LP tractor.)

That's what he said.The real reason is it was a byproduct of oil drilling and it didn't have the market share it has now.They used to practically give the stuff away.

Vito

I've run LP tractors since the early 60's & the reason they were popular in the south was that propane is a byproduct of cracking crude to get reg. gas & diesel products & back then LP was sold for .04 cents a gallon..when I was in HS [1960]everything on our farm ran on it including the MF lawn mower...all our cars & trucks had tanks in the trunk & we would inject it into the diesel tractors we had for a little extra HP...at that time Butane was mixed with Propane so it wouldn't freeze up in the winter...my brothers & I have several LP tractors now & they can be filled with a BBQ grill tank by turning it upside down although it is a very slow operation it will get you back to the nurse tank...I have won much beer money by betting with my intown friends that I could carry LP in a plastic 5 gal bucket...when we were harvesting in the cold we would use the liquid line to fill a metal grease bucket & light it up nice heat no smoke & 5 gal would burn about an hour enough time to get ready for the field & it smells so gooood coming from a LP tractor under load...take care ...Kent from Miss.

Do any of you guys remember how much propane those combines would burn through at full load?

John Harmond
I worked at a supply house and the people that worked in the warehouse would steal gas out of trucks to put in their cars, And they were getting union wages. By the way they were White Stealing has nothing to do with Race People that steal are just low lifes. The first thing I always did after cashing my check was fill my gas tank up that way I had gas to drive to work the next week.