Bobcat propane conversion

[SkidSteerSteve]

I'm considering putting a conversion kit on my bobcat. There's two main reasons I'm looking at this. One, I really don't put a lot of hours/year on it, so there's always that fight with varnish and gasoline stabilizers. Two, if I ever need it for long term power, I can tie it into the tank for the house. My question is how much run time can you realistically get from a forklift sized bottle. What are those, about a 30Lb bottle or so? I was considering using that for my day tank. Anybody that has a machine set up this way I would appreciate any comments pro/con about it. Also, I'm assuming they are a vapor draw system since a 20hp engine wouldn't use a whole lot of fuel. And, are they set up so that you can switch back to gasoline if needed without replumbing the entire intake system.

Thanks,
SSS

[Toysrme]

Eh. personally I wouldn't do it on a skid-steer type machine unless it had a turbo & you were after more power. Propane by itself doesn't have the energy density that diesel fuel will have. You'll wind up loosing some power runnign straight propane.
Where propane is really affective is when used as a secondary fuel to diesel on a forced induced (Turbo / Supercharged) application.

The expanding propane gas decreases the temperature of the incoming charge. Lower temperature is higher density. The more air that's stuffed in, the more fuel you can burn, the more power you can make. Propane also quickens the combustion process of diesel fuel. More of it is combustion in the combustion chamber instead of flying out the exhaust valve & burning when it hits an exhaust ports, manifolds & turbine.






Oh. And why on Earth do you have an idle bobcat!? You know those things rent for good amounts of money through whatever your local paper is right? Great supplimental income.



Fuel stabilizer is not rocket science either. You have X amount of gallons of fuel, you use Y amount of a good stabilizer.



Personally. I think it's a waste of time & money unless you're looking to crank up the boost on a turbo diesel so you can burn alot of fuel & keep it abit safer.

[calweld]

Uh . . .

are we talking about a bobcat skid steer or a bobcat welder??????

[harcosparky]

Uh . . .

are we talking about a bobcat skid steer or a bobcat welder??????

My money says SSS is talking about a Bobcat Welder.

My clue came from this line .....

Two, if I ever need it for long term power, I can tie it into the tank for the house.

Be kind hard to use a skid-steer tethered to the home propane tank!

[SkidSteerSteve]

yeah, definently talking about the big blue box......besides....don't cuss like that around my CAT skid steer.....once you use pilot controlled hydraulics, you will never go back to a lever controlled machine that hasn't had a major design change in 30yrs...but I digress

But...this is not the first time I've had this confusion....

Anyway, so if anyone has expeirence with a propane conversion on an Onan powered, Miller Bobcat 250 engine drive welder, I could use some info

Thanks!!
SSS

[FusionKing]

I thot they sold them NEW?? (factory equiped) at least 10 yrs ago I think they did ( Great Idea on the house tank BTW)

[84ZMike]

Yes propane will produce less horse power......you can get kits to run duel fuel (propane or gas)....not sure about for the Bobcat......if I were looking at going propane I'd go all the way no duel fuel as it can create problems....if you do go propane for a period of more than 250 hrs or so NEVER NEVER go back to gas.....I have seen fork lifts that were run on gas then LP then someone gets a wild hair to convert back to gas and well they don't last much longer after that.....as far as run time well that will depend on you.......idling it would probably run for 60 plus hrs on a regular size fork lift tank......but as far as welding etc it would very....I'd estimate you'd be able to get a solid 15-20 hrs to a tank.....just remember to turn the tank off with the eng. running at the end of every day of use especially if it's cold out.....you wouldn't be able to use a fork lift tank as they draw liquid and your Bobcat is air cooled so no way to convert to vapor...I could be wrong but all the ones I have seen used regular stand up bottles that draw vapor.
Good Luck,
Mike

[calweld]

if you do go propane for a period of more than 250 hrs or so NEVER NEVER go back to gas.....I have seen fork lifts that were run on gas then LP then someone gets a wild hair to convert back to gas and well they don't last much longer after that.....Mike

I'll second that statement. About 20-25 years ago one of the local propane companies did a major updating on their fleet . . . dumped a bunch of propane-engined Chevy one- and two-ton flatbeds. Bunch of guys picked them up relatively cheap, some converted back to gas, others kept propane. Almost without exception, the gas conversions only lasted a couple years before blowing up, the ones that stayed propane ran and ran and ran (and some are still going today).

[TomVeatch]

...the gas conversions only lasted a couple years before blowing up...

Anybody have any ideas what would cause this? Not doubting your word, just curious as to why it would happen.

[calweld]

I really don't remember what was happening specifically, at one time I knew, but most of this happened 20 years ago. I'll have a chance to see somebody who did one of these next week, I'll ask him if I have a chance. Probably somebody who knows more than I will have the answer before that anyway . . .