Just read an article in Motor Home Magazine about dual fuel vehicles, gas and propane. Apparently unsafe and gone off the market. But the writer said to use gas or propane efficiently, the compression ratio of the engine has to be 12 to 1. For gasoline it has to be 9 to 1. Propane run in a regular engine would be very inefficient and therefore it would cost more to use propane that way. I had a 25KW generator in 1999 when I thought the world would end for a little while. It was designed to run on either natural gas or propane. Very efficient engine. Question is, how would you convert a big block chevy to 12 to 1 so it could use propane? I've seen pics of a Barth in Canada that ran on propane but have no idea of what they did to accomplish that

From personal experience I have to question the assertion that you have to have a 12 to 1 compression ratio. Some years back a lot of friends worked for a large propane distributor in the area and they would convert employees cars for free. I'm pretty sure Patty's old Plymouth Valiant wasn't making 12 to 1. Everyone said their cars ran great and milage was very good. At that time, when the distributor was still here, all the Venice city vehicles were converted too. This would have been late 80's. They claimed great savings and cleaner engines. Unfortunately, the LP place left town and everyone found the down side of being LP converted. Lack of filling places.
Personally, I had a 81 Ford pickup with the straight 6 that was a fleet truck up in Indiana before my buddy bought a bunch of them and converted them back to gas. It had well over a hundred thousand miles and at changes the oil was so clean it was scary. The only issue was rust in the gas tank stirring up and clogging the filter.
If any of you engineer heads can clarify further, I await your wisdom, but I think the main drawback of LP is lack of availability, especially on a long trip in unfamiliar territory.

LPG does not NEED higher compression, but it has anti knock qualities (110 octane rating) that make higher compression work well, yielding more efficiency.

At work, we had a fleet of propane vehicles with no safety issues. They were cheaper to operate and cleaner burning. We filled from a big tank or a smaller tanker truck. We seldom went off the airport very far, though, due to lack of fill points. The oil and filters needed changing much less often, owing to less contamination from combustion by-product, according to the analyses. The engines were a mix of high and gasoline compression ratios, depending on the manufacturer.

I think propane is 135 octane. Back in the good old days Minneapolis-Moline sold a ton of propane powered farm tractors. Why, because the produced more power on less fuel than the same engine on gasoline.

The difference was compression ratio. At good propane engine will have a minimum of 12.5:1 compression and I believe the tractors were even higher. In addition it had a different camshaft. Got's lots of hours in the seat.

There was an article on the net a number of years ago about a Canadian who built a 454 Chev engine for his PU to run on propane and it got better mpg as well as more power. So check the net for article.

Hey there guys. A propane fired engine generates 20% less power than the same engine running on gasoline. The reason is that on average a gallon LP Gas (Propane) contains 94,000 Btu's of energy while the same amount of gasoline contains about 120,000. This is the main reason why we try to educate folks considering an RV generator. LP is quick and easy to install, but very expensive to operate when compared to gasoline. They (LPG fueled engines) do run very clean though.

Raising the compression ratio squeezes out more power but at 12:1 you will be eternally "propane only" as pump gasoline to support that compression ratio are long gone, unless you retard the timing to keep the engine from pinging. If you have to do that, then what is the point? Also remember that when you use propane as a motor fuel, the retailer will tack on the highway taxes which vary by state, but around here is around .42/gallon.

The home standby generators can operate on either LPG or Natural gas simply by configuring the fuel regulator to do so. Natural gas has even less energy per "gallon" than LP Gas. Natural gas is sold by cubic foot and there are 7.48 cubic feet in a gallon


Something to think about.

Thanx for the info Billy. Hope the home front was OK when you made it back.

Oh yeah, Thanks for asking...I will post this in the Barth Travels forum too:

We got home around 3 pm yesterday. Trip from Jackson, MS was uneventful but a car got tangled with some utility trucks on the Westbound Basin Bridge between (Baton Rouge & Lafayette). We decided to take the 151 exit, but as we were crossing the Mississippi River Bridge @ Baton Rouge a tremendous gust blew through, knocking about a dozen utility poles down along the road forcing us on a two-lane road to get around all of that. About a mile into that we pulled up behind a stopped big rig. We all got down to check out the situation and found some guys cutting on a 3 foot thick oak blocking the road. With no where to go, we all got involved and helped them get most of the left lane open. We were able to maneuver the Barth around the protruding tree trunk and motored the rest of the way home! Good news is, no damage at home & the shop had three of the four bay doors blown out, but we will open for business again on Monday.
Billy T

Rule of thumb is propane has only 75% of heat units of gasoline, but higher octane allows higher compression, increasing efficiency. This results in only a 10% fuel consumption penalty compared to a gasoline engine doing the same work.

For our equipment at work, which all had hour meters, it worked out about like that. The vehicles that had odometers yielded varying numbers, perhaps due to the variabilities of usage and operators.

Propane Powered Barth For Sale

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