OK gas is going to top 3 bucks a gallon. I've seen propane conversions, also more practical duel fuel (gasoline/propane) conversion kits on the web. I've seen our fork lift converted to propane from gasoline in my shop, but has anybody any experience with a duel fuel conversion on a super slant 6. I have a pick up, so tank placement is not a problem.

Any comments?

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There is no problem that cannot be solved by the proper application of thermo nuclear weapons

red green did that to his van.............he heh.......

hey.

lots'a propane vehicles down here in argentina (in fact I believe that we're the leading country in this kind of technology)

pros:
40% less emissions
cheapo-cheapo (something btwn 1/4 and 1/3 of the real stuff)
greeat for hi-comp engines like above of 10:1
you can greatly advance your timing curve (I.e. I had a friend that had a slant with propane and initial was 19º BTDC total was 45º BTDC performed great)

conts:
"dry" explossive combustion that dries out and sometimes cracks the rings
less overall engine durability
you loose trunk space
I don't klnow up there, but down here even being one of the leaing areas in propane conversions, you can't go everywhere and find propane readily avalible for your car (ain't the same as commercial propane in bulk tanks, the pressurization is diffrent)

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

In case anyone is interested, I just finished writing a web page on dual fuel conversions. Although it doesn't specifically cover slant six dual fuel conversions, the concept is pretty much the same for TBI as it is for carburetors.

Dual Fuel TBI Propane Conversions

Since you have pickup truck, you may be able to stack the propane mixer on top of the carburetor but, if hood clearance is tight, you may have to use a remote offset adapter (like Impco's UNIDAPT adapter system) instead. I hope to get photos of more conversions (including slant six conversions) in time.

If you are in an area where propane is readily available (remember any bulk propane supplier can fill your tank), you may also want to consider a straight conversion because of its better fuel economy. A straight conversion on a slant would be very similar to Tom Jennings' Rambler conversion: http://worldpowersystems.com/AMC/LPG/.

To counter some popular misconceptions, engines running on propane last far longer than gasoline engines and propane is much more readily available than most people think. Propane engines last longer because the dry nature of the fuel does not wash lubricating oil from the cylinder walls. Especially with the large fuel tank that a pickup truck can carry, finding propane should not be an issue in most parts of the world.

Frank

There was just a propane carb for a slant engine on ebay

http://cgi.ebay.com/ebaymotors/PROPANE- ... 9665QQrdZ1

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1966 Signet
Turbo Slant Six

i was very interested in this a while back and did a lot of reading on the subject. the dual fuel deal is more practical if you do a lot of highway driving or road trips since gas is easier to find, but i'm wondering how it would work from a performance standpoint.
all else being equal, an engine switched to propane from gasoline will lose something like 20% of it's power because propane does not have as much potential energy as gasoline. however, that power can be reclaimed mainly thru an increase in compression of a few points. starting with say 9.5:1, a move to 11.5:1 would work well. detonation shouldn't be a problem since propane has an average rating of 106-108 compared to what pump gas is in your area (i think ours maxes out at 92 here in chapel hill, i try not to look at the pumps these days!) the thing with increased compression is it's kinda hard to switch back to running gasoline (no longer a bolt-on.)
propane and dual fuel conversions have been used in fleet vehicles for many years and if i'm not mistaken, fairly popular in Canada (sandy or dan may have some experience here) so many years in fact that with a little web browsing you can find a few propane vehicle "junkyards" and other parts sources to make your swap a little easier/cheaper.

-james

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Generally, you don't install a dual fuel system for the performance. Obviously, the main reason to convert is to save money on fuel and this only makes sense if you drive enough and there is a big enough spread between the prices of the two fuels. Even with the slight loss in power, there is still plenty available for normal driving. I have a sample calculation you can do on my conversionspage to see it it makes sense for you.

You do regain some of the power of the engine by increasing the compression ratio and 10.5:1 is a realistic limit because of propane's 104 octane number. However, you are right about this not being realistic for a dual fuel engine because you would also have to run high octane gasoline. The performance loss actually comes from the gaseous fuel displacing some of the air required by the engine rather than from its lower energy content per gallon. Interestingly, propane has a higher energy content per lb but its lower density results in the lower energy content per gallon.

As far as performance goes, I know of one propane drag racer. Gas Injection Technologies in Australia have conversions(not available here) that outperform gasoline systems.

forget duel fuel!! i say hydrogen!!

How much compression can hydrogen take without pinging?

Hydrogen doesn't ping...........................

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It explodes

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Back in the late 70's I had a dual fuel car. A little different from the injection systems available today. Had to pull a lever to recirc the gasoline back to the tank, (Mechanical Fuel Pump,) then wait till the carb ran out of gas. At that point, throw a toggle switch to turn the solenoid feeding the propane injection on. Going back to gas was the oposite, but with no waiting time, since it ran out of propane in short order when the solenoid enable was turned off. Screwing up and turning the propane on before running out of gasoline killed the engine, or made it run terrible.
The injector was piggy-backed to the top of the carb, and used a TPS. The propane flowed through the factory carb.

The system I had didn't have any on-the-fly adjustment for timing, so we had to time for a happy medium between the two fuels. Newer kits should be able to do this.
Because the ignition wasn't optimized for either fuel, mileage was poor.

When in town, or pulling a hill, I'd run gasoline. If I was running on Propane, I could blast a "quart" through it accelerating across an intersection. Pulling the pass would result in slowing down, and going through a lot of fuel while on Propane. Gasoline was the best answer.

Power was down about 30% on Propane as compared to Gasoline with that particular "Kit." Economy suffered at the same rate.

Presently I have a work truck that is a dedicated Propane rig. It takes it a while to figure out that the throttle is mashed. The engine will spin up, but bottom end is dismal. When it's spun up in it's power, there isn't much difference. I don't pull hills with it though.

For a personal road vehicle, the added cost of the hardware, and the loss of economy make a propane conversion less attractive. If fuel cost is the issue, I wouldn't bother with it. Price a gallon of Propane with Road Tax. (Not at the propane dealer, out on the road where you'll end up having to buy it.) It'll be about the same. In some places it costs more. The one big plus is lower emmissions. It is very clean.

When running propane, it cleans the combustion chambers out very well on a dual fuel rig. No carbon deposits.
On a hot day, you may experience a tank vent. Had it happen a couple of times. Car's sitting in a hot parking lot and just spews out the relief. I'd call that a drawback. (Unless you consider the alternative of a bleve'd tank.)

CJ

Anyone know how to select the right carb/converter?

If I had to get all the parts new, I would not bother, but a used system might be interesting...

And it is not going on a 350, so I can´t find much useful info

Ceej, it doesn't sound like your work truck's propane system is properly set up. Its propane gas mileage should 75%-80% of its gasoline mileage. It should also have similar amount of power and should run very smoothly. Your fuel tank is spewing propane on a hot day because it was overfilled. Propane tanks are designed to filled to a maximum of 80% of their total capacity to eliminate any chance of spillage from the safety valve. This is done either automatically with a stop-fill valve (like the water valve in your toilet) or manually when propane starts to issue from the spit valve. Also, propane prices are very dependent upon location. Motor fuel propane in Toronto sells for around 45¢/l to 50¢/l (all taxes included) compared with ~$1.00/litre fo gasoline.

Rust Collector, for an Impco dual fuel mixer look for a Model 125M-10 or 175A-1. The Model 175A-1 has a better selection of adapters available for cars with low hood clearance. If you are interested in a straight conversion, you will need almost exactly the same components that Tom Jennings used in his 1963 Rambler.

Thanks, I found that site later yesterday

Can I use "any" propane carb (with the right size) in both single and dual fuel, with different adapters?