I looked into converting the 250 six in a '67 Chevy Pickup I'm building as a parts chaser, and was dismayed by the cost of all the hardware required to retrofit it. And, as has been noted by others, the issue of finding fuel away from home made me have second thoughts. Back in the day, when agricultural equipment ran on the stuff, farmers all had a hundred gallon tank in the bed and a big mother of a skid-tank to fill their tractors and other equipment. I don't think road tax was in their vocabulary. I was willing to deal with that, my idea being, first and foremost, to save money so I could cruise around looking for car stuff. Instead, after doing the math, the buy-in and the hassle of filling the tank changed my mind. I'm still a fan of alternative fuels and keep hoping that the infrastructure to use them will be brought into play before gasoline gets to five bucks a gallon. But, being a pessimist when it comes to good ideas being put to good use, I'm not holding my breath. Not while there's money to be made by the multinational corporations who control energy distribution.
No. You are right about the fact that a POS engine on gas will still be a POS engine on propane AND you are losing 10% BTU plus some airflow due to vapor carburetion. BTW, your "fix" for the 300 has the idle so rich that it shouldn't run at all. I'd put $100 on a vacuum leak, which is no fault of the LPG system.
Sundays are lousy for trying to work on anything, all the real parts stores are closed. At least the truck is not stranded anymore. Maybe on Monday I can find a vacuum gauge and have another look, but the truck has never run so good. The stink seems to be much less too. Maybe if I call Impco I can get a tune up/adjustment procedure guide without having to "Join" another forum to download a "Free" manual?
You guys also gotta remember that the OP lives in EUrope where they can only dream of $3.50/gallon. When I lived in England I remember that Autogas (LPG) was about 40p (65c or so) a Liter while unleaded was about double that or more. Pretty much every older V8 powered Range Rover, BMW 740, Jaguar, etc that you'd see had been converted to LPG. Not much market over there for a $3,000 car that gets 15-18mpg at $6+ a gallon.
Well, NONE of the threads I found on line were at all helpful, so I fumbled my way to success as best I could. If this were a gasoline engine I could fire it up and spray some water around to detect any vacuum leak, looking for an RPM increase, hopefully that still works? I wish I could just send this truck to the junker, or Craigslist, even though the engine has low miles on a professional rebuild. But I'm stuck with it until I get the 54 Willy's/Chevy put together.
You have obviousy got a problem with the set up and/or maintenance of the system. I installed as well as drove propane powered trucks for years and they are much more reliable than gasoline. They are also cleaner burning so things like Oil and plugs stay cleaner. The number one problem with a down on power system is that the filters are dirty and/or there are leaks. Propane leaks will be evident by the ice build up on connections. Tighten the connection. Vacuum leaks allow air into the digestor/vaporizer/mixer and that will cause the engine to run extremely lean (lack of fuel or too much air for the fuel being supplied) Vacuum leaks will usually stem from the gaskets/seals in the regulators/mixers allowing air in. Tightening all the screws/bolts on the mixer/regulator often helps fix a poor running engine. The biggest problem I had over 350,000 miles on my Ford was that the spark plug electrodes wear down into the plug and the gap opens up to be in the neighborhood of .125+ which causes a poor spark. The other problem I had was from air leaks as per the screws/bolts on mixers/regulators. Never was I stranded or let down and that Ford got 24 miles per Gallon with a V8 + overdrive. Back in the 80's, LPG was hovering around 50 cents per gallon when gas was $2.00. We had a LPG gas war in 1988 that brought the price of LPG down to as low as 9 cents a gallon. The cheapest I ever got it for was 28 cents/gallon. I drove to Yellowstone National park and back (1500 miles) on $15 worth of fuel. .
Called IMPCO. They connected me to one of their vendors. There is no manual for these older systems. 1. Ignition. A. Propane requires twice the voltage of gasoline to ignite. REDUCE the plug gap to .025 NOT the .035 that is normal. B. Max advance of 30*, if your distributor has an 18* dwell all in (about 2500 rpm), set initial timing at 12* C. An MSD box or similar can help quite a bit on older vehicles, an HEI ignition should suffice. 2. Initial set-up. A. Remove the air filter, reassemble the mixer. B. Screw the idle screw in until the ring just begins to lift. This should be close to idle. C. Reinstall the air cleaner, adjust the idle. 3. Once idle is achieved road test the running mixture for best economy. A. Start with the power valve centered, or to the R side if necessary to get decent acceleration. B. Move the power adjust to the lean side, check acceleration. Continue to the L side until acceleration drops off, then go back to the R side until acceleration is restored. So long as the components are in good shape this SHOULD be all we need to know for mixer type systems. Now I get to re-gap my plugs, check my timing, etc., what joy!
I have a 454 on propane under 14 psi of boost. Here fuel costs about 1.84 a gallon. Maybe your states tax it more than mine. If you are real cheap you can get a 1000 gallon home take and put on a fill valve. Of course that is illegal. Mine gets 8-9 mpg when driving it like I have a brain. Still that it about like 14-15 mpg with the cost to me. It is on my rock crawler so I will run at angle and I would guess upside down (have yet to try it). It will smoke the 36" tall swampers at 30+ mph.
Fyi propane likes LEAN and LOTS of timing at highway speed. Most people think if the egts are high it needs richening but since there is no cooling of the fuel when it evaporates like gas has it will just burn in the pipe and melt the exhaust valves.
I've been running LPG on my 71 ford 3/4 ton truck for 30 years now and it runs so nice and inexpensive. I love it.
Yep, Knew all about the various diaphrams available. They are knda limited now, two I think, but there is still a lot of NOS inventory available. I have converted two vac secondary holley bases to a 1:1 mechanical linkage. I plan to run a progressive rod on these, opening them in stages with one doing the low speed primary role, stepping up to both wide open when the pedal is down. The response difference is probably more about the port design than anything. Those tiny Ford ports promote velocity and torque. There are two really knowledgeable guys out there that you should get to know if you are doing your own LPG conversion. One is Frank Rasso out of Canada. He's great for parts, including some very performance oriented aftermarket stuff. Frank is a HAMB member, but fairly occaisional is his appearance here. The other is Franz Hoffman. He is the leading collegiate authority on alternative fuels in the US. He lives just outside Austin and is the go-to guy for the Feds and several industry groups, universities, etc. He has lots of lab time, including dyno testing, etc. he can explain the technical side of most any issue you run into. He publishes a tuning and troubleshooting guide that you can get electronically from his website. It's a must have for any DIY LPG builder. I think it was about $20. Here's their websites: http://fuelsforum.rasoenterprises.com/index.php http://www.rasoenterprises.com/index.php http://franzh.home.texas.net/ Some fun reading, Richard has some serious race cars on propane and CNG: http://www.alternatefuelsracing.com/
I run LPG (Propane) on my Ford Explorer SUV. It has paid for itself already since installation. Starts on gas and switches to LPG when it gets warm. Plus I can run on gas if I so desire by flicking a switch. Very common downunder as stated, most taxi cabs run it or are Eco friendly Prius or similar. IMHO well worth the initial outlay. Sold everywhere here is easy to find. 1/2 price of standard gasoline.
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