propane conversions?

[wacko]

Hello All,

There is a '75 brave for sale locally that has a 440 running on propane. Just wondering what peoples opinions are on this?  Pros and Cons?

Thanks

[Oz]

Well, we have had a few members with RVs converted to propane.  Mostly in Europe due to the outrageous cost of petrol there.  I can't say what the performance/mileage comparison is as, well... I just don't remember  i??   LOL!

[HandyDan]

My Holiday Rambler came from the factory with the dual fuel option.  There was a recall to have the propane part removed but mine still had it.  When I got my HR three years ago I had so much trouble getting the motor to run on gasoline I never got the nerve to try propane. When I took the motorhome into the Chevy Truck Center to have them fix the motor, they put on a new carburetor and disabled the propane.  I finally removed all the lines and regulators.  Never did find out how propane would work.  However, from what I have heard, it isn't as dangerous as I had visioned.  It is liquid propane up to the air cleaner and then sucked in much like gasoline and then converted to vapor.  I would think that propane would be a viable energy source but if on a trip, it might not be as easy to find a fill up as gasoline. 

[lewism61]

I have done some on line research about converting a 440 to propane.  Similar to an Onan generator propane conversion, there are advantages if done properly.  As I understand it, propane has a higher octane rating than gasoline (approximately 110) that eliminates concerns over knocking due to poor gasoline.  Propane does not go bad and plug up the carburetor when the RV is stored over the winter (no ethanol).  Plugs and oil last much longer.  Tailpipe emissions are greatly reduced. 


Potential downsides are less power or mileage due to the lower energy content of propane.  The real world difference is dependent on the engine's compression, ignition tune, and camshaft profile.  It could be that an engine designed to run on 1975 gasoline could run better on propane than 2012 gasoline. 


Another and perhaps greatest downside is the hassle in filling the tank.   With gasoline, one can roll up to the pump, swipe a credit card, fill up and hit the road again.  With propane, I'm not aware of any stations that don't require hunting down an attendant, waiting through a lengthy filling period, and going into the station again to pay the cashier. 


All said, if the conversion was done properly and has all government required approvals and/or permits, I would think it should be a viable alternative to gasoline.




Although your question was just about a straight propane conversion, the hot set up appears to be propane in combination with a turbocharger.  If you Google "turbocharged propane 440" you can find some impressive conversions Mopar gearheads have put together.

[Oz]

Did a brief message search and here's what I found on the quick (I have to go to work in a few):
http://www.classicwinnebagos.com/forum/index.php?topic=287.msg287#msg287

[dezertgurl]

 I'd agree with lewism61 about carburetion issues. I don't have any experience with conversions, but for what it's worth, here's my experience with running propane. 

We have a 93 Ford one-ton with a 460. It was formerly owned by a propane distributor, so runs on propane only, no gasoline. We use it as a service truck in our business so it's always carrying a fairly heavy load, and it gets a consistent 4 MPG. It has 5 tanks totaling 60 gallons of propane, but that's still not enough to let it venture too far from home.  Those bulky tanks are real space hogs too.

The engine has 200,000 miles (40,000 since we got it) has never given any problems, runs clean and will probably last far longer than the truck itself. But it's no powerhouse, best you can say is it gets down the road and back. Our other service truck with a gasoline powered 460 gets 7 MPG, but we do see wear and tear issues with that engine.

For us, it pretty much comes down to price per gallon: $1.55 propane vs. $3.50 gas. That and availability of fuel, we have to keep a 500 gallon propane tank here since there's only one propane retailer in this area.

[ClydesdaleKevin]

The biggest problem with any alternative fuel source is availability and the infrastructure of this country, which is dominated by the oil industry.  While it would be quite easy and relatively affordable for all gas stations to add a propane lane, that would cut into their high profit margin.

Kev

[canamfan]

Old thread but had a few thoughts. New here looks like a great forum, lots of good info. My 75 Winnebago custom with a 440 which I have recently started resurrecting has a propane conversion, looks like it's all there the part that fits on top of the carb was in one of the storage compartments. So not operable right now. I don't know much about these, there is a large tank of course with a valve regulator? mounted underneath by the engine large hoses going to it, and a fuel solenoid shutoff which works. I don't really think I'm interested in keeping it, to many other things to look after on this MH. Do any of you run this setup. Also I have never seen another 75 custom model like mine, it has a totally different front fascia from other winnebagos of the era. There must be some out there. It's a D27L  1975  m500 chassis  178" wheelbase

[DaveVA78Chieftain]

1975 Winnebago Custom Brochure

[roma]

Propane conversion is done almost everytime in europe due to the much cheaper fuel price . The big v8's drive very well and they are driving on both fuels. They use a little bit more fuel with the gas but drive very smooth.
On the old caberettor engines we mostly use impco parts for the gas rebuild.

[TerryH]

Mine (in Canada) is dual fuel. When I was in the market for one included requirements were either so equipped or able to be converted. Large consideration is a location for the large propane tank that fits code, available space and is reasonably compatible with vehicle weight distribution. Fortunately this one was already converted and weight at 4 corners was acceptable.
Mileage - I see no difference. Power - I see no difference. Performance of the engine - I see a large difference in favor of propane. Fuel cost differential - generally propane is approximately half the pump price of gas. I do in honesty run primarily on propane.
I do regularly run +- 100 miles or so to keep my gas fresh, and because there is no lubricating additive/factor with propane. Think seals etc.
As for availability: Canada - no problem. Virtually anywhere you go it will be readily available. USA - I haven't driven there within the last couple of years (reason is a whole different topic), but earlier in this decade I did frequently. I did have trouble finding smaller town gas stations that were able to fill a 'carburation' type tank. Most were set up to fill portable tanks by weight. However, by checking ahead I was able to adjust my route if needed. Any town with a propane supply depot had no problem filling me.
Degree of difficulty was minimal.
When I had my business I ran 5 service trucks, all within 3 years of manufacture, all GM 350's, 3 dual fuel and 2 gas only. Operational cost per mile including fuel, lubricants, maintenance and time loss for previous worked out 55% less for the dual fuel units.
Personally I would not even consider propane only. Dual fuel, to me, would be the only way to go.

[canamfan]

If I keep the propane, i'll have to find some kind of manual for this system. I've not had any experience with them. I do have a late model chevy pickup that runs on gas or cng but that's a very complicated system. Dave the link you posted won't open for me but I have seen an ad for the 75 custom, that Winnebago put out.

[TerryH]

Your system is likely Impco or similar. Google and email may help.
For a carbureted engine it is reasonably simple. Enough so that I changed more than one of mine from vehicle to vehicle.

[canamfan]

Thanks I'll do my research