i have a 79 ford pickup with a 302. i would like to get better fuel economy. its 4 wheel drive and want to keep it. but fuel costs are getting ridiculous. would changing to propane make it more barable. i know i will lose some power i am not concerned about that. any personal experiences or info would greatly be appreciated.

thanx broncoman79

 

There is a coule of companies down here that have converted their company trucks to natural gas. The mileage is a bit better and the operating cost was lower. But since the last round of natural gas price increases I am not sure that is still true.
After about the third generation of conversions the power was about the same as what it had with gasoline. That was 10 years ago for the third generation conversion.
Even if it is still cheaper to operate, the cost of the conversion is going to take a long time to recoup before you start to see savings.

 

doubt that you would get better mileage...but will pay less for fuel as long as you do it right. I'm doing it but am building a motor just for that purpose.

 

The only time propane is worth it is if your converting a big block engine like a 460 or 534 or any other big block engine that doesn't run that great on a carburator. A engine on propane is kinda like a engine on fuel injection it starts easy as the fuel is force fed where as a carburated its venturi.

A 302 on propane is going to be gutless your going to loose quite a bit of power. You will also have to redo the heads with harden valve seats you will also have to be prepared to repair oil leaks propane is dry it causes seals to dry up and you end up with leaks.

If you are going todo a propane conversion look at spending atleast couple grand CND. Here in B.C. a certified shop has to do the certication you can do your own installation but it has to pass inspection.

Anyhow you will be spending hundreds to save pennies its not worth it.

 

I will move this one to the gas alternative fuel forum

 

By what theory will it be gutless? Also you will not have to redo valves as long as it is a 73 or newer motor. YOu can raise CR a lot if you want because propane has a octane of about 110.

 

B-man79, well, it will depend on what is the cost of propane in your area. If it is substantially cheaper than gasoline, then yes, it would be worth it. If propane is only cheaper than gasoline because it doesn't have road tax on it, will the gov't in your area ask for you to pay what the road tax would have been if you had used gasoline ? Conversly, does the gov't in your area offer any tax credits for converting to alternative fuel ? Lots of places do. Sounds like you have some math to crunch out, and see where the numbers fall. If you lose power on a propane conversion, something wasn't done correctly. DF,@ his Dad's house

 

To get the power out of a 302 on propane you will have to increase the compression ratio and run a RV cam. I have had 2 trucks on propane I hated it they burned more fuel than they did on regular gas. One truck it was 460 on propane the sucker would suck down 30-40 dollars worth of propane like nothing. When I converted the truck back to gas it had alot more power and it got better fuel mileage.

The main reason why I converted back is the system on my truck needed re-inspected the tank needed replacing plus other parts needed replacing. I priced it out it was cheaper for me to buy a brandnew gas tank,remanufactured carburator and fuel pump than it was trying to get the propane system legal again.

The DOT here and the rest of Canada has clamped down on propane systems they really tightened the rules. The reason why is the Taxi cab companies in Vancouver B.C. running Taxis with improper and very dangerous set up propane systems running their cabs. It was pretty leinient before but now everything has to be absolutely perfect if there is something wrong your vehical is pulled off the road.

One of the shops here used to install and service automotive propane systems when propane power was common as propane was 30 cents a litre compared to gas in that day was 60 cents a litre then some parts of Vancouver you could find propane for 10 cents a litre. When you had a big old 454 or 460 Ford it was worth it to run propane if you could get it for 10 cents a litre.

I haven't checked what the price of automotive propane is per litre lately its been 10 years since I had a propane powered truck.

 

Power should hbe the same if it mixture is correct and you have to run more spark than stock because it burns a bit slower and if stock timing is used power and MPG will suffer. Also Propane ha about 30% less heat energy ,per gallon so more of it is required to make same HP unless you raise CR ratio a lot to help offset this.

 

Its why alot of people that run propane run a RV cam or something a little lumpy. You also have to watch propane you can lean it out and have a melt down like a diesel it happened to a truck my dad bought. The truck had a 454 on propane it had a few melted pistons it seized up solid. My dad bought the truck that way and turfed the engine converted the truck back to gas.

 

i dont know where you get the idea seals are going to dry up,my truck runs great on propane,never leaks,has tons of power.its all in the way the conversion is done.just like any motor modifications,you get people that know what they are doing ,and idiots that should never open the hood on anything. i run a 428 SCJ on propane in my 74 4x4 dually,i pull a 38 foot tri-axle enclosed racecar trailer that is over 11000 pounds.i dont get much passing me on any hills through the rockies.my engine was 425 horspower new in the crate,it is now more,but ive done more work to it.the truck was chassis dynoed at 428 horsepower (to the ground).i would never go back to gas again.i may go to a deisel engine one day,but im happy with the propane.

 

Propane is a great motor fuel, especailly if you take the time to set it up properly and run very high compression to take advantage of its very high octane.

 

I have 01 Lightning with a gas conversion and there is no difference in power and the fuel consumption if far better, however I do live in the uk and petrol is $1.57 per litre compared to 64 cents per litre for gas. The system I have is a Prinz system specifically designe for my lightning, prins are Norwegian but the have distributers in the US.

Dont know how much help this is, but its good to talk.

 

The 302 in that truck is already underpowered. My metro could take that on the 1/4 mile. I'd say you probably cannot afford to lose more power on the conversion. On the other hand, you may be able to re-build the 302 to get you about 16-18 mph in the old '79, which ain't bad! You may want to consider a mild build with an increase in CR, and more efficient engine parts. The stock 79 engine is pure garbage from the factory, but is bursting with potential with the aftermarket performance parts available.

That's my 2 cents worth.

 

Info here has been useful. I bought a old F-150 with a propane conversion two summers ago when propane was cheaper than oil. I was able to complete my summer roadtrip but now this baby has a major major oil leak. Little puffs of smoke coming out of the oil fill stem, but it got me home fine. Had thought about rescuing it as it was grandfathered for smog but with the price of gas down and a quote for engine repair more than what this baby cost me, I will have to let it go.