Posted by David Sherman on Friday, July 29, 2005 at 9:01PM :
In Reply to: Anybody converted to propane? posted by Charlie on Friday, July 29, 2005 at 8:20AM :
Don't know if this helps, but if you're scrounging junkyards there was a John Deer tractor that was available in gas, diesel, and propane models, with basically the same engine. The only difference between propane and gas was a propane vaporizer unit that took the place of the carb (used engine coolant to keep from icing up), and the crank was ground for a higher compression ratio. To take advantage of propane's higher octane rating, you need to raise the compression ratio. If you do that, you can get as much or more HP per cu inch as with gasoline.
Thinking of conversions, I once knew a guy who had a large collection of old one-lungers he'd gotten from an oilfield in Montana where they had run them off of natural gas pretty much straight out of the well-heads for years. Between the natural gas fuel and the dry climate, these old engines looked pretty much like new inside and out. The biggest one was an "Atlas" that had a cylinder that must have had about a 2' bore and a 3' stroke. It too looked almost like the day it was made 100 years ago.