The Stovebolt Site Forums The Shop Area Engine Shop Using Propane to Power our Trucks

blanch 53 I heard complaining about exhaust fumes at a parade last fall,now I don't have the only AD truck in this whole group that burns propane for that exact reason,but it sure doesn't pollute like those cammers !! My reasoning is clean oil,no sludge,economy,never cold natured,no fuel pump,no dirty rusty gas tank,no messy fuel filter(is dry) no sorry liquid fuel carburetor to fight is easy to trouble shoot,buy AMERICAN made parts brand new from the internet. 78 buckshot is right about kill the catylyst. Your 57 is an ideal candidate could run 12 to 1 compression too. Also have an 04 GMC injected propane EPA certified dual fuel is automatic switches fuels on it's own just punch the button. Sorry read it wrong 78 buckshot has the 57 283 my bad . Should have said or punch the button to change fuels if you need to.

Have you done any analysis around miles per gallon, so to speak? How does the miles/cost of propane compare to the miles/cost for gasoline I know the cost are always fluctuating but have you done any comparison. One tank of propane cost $99 and I can get XYZ miles, as opposed to XYZ miles uses $?? worth of gas.

dgrinnen I have done propane for 44 years using mostly used equipment,my 04 injected 4.8 GMC got about 13 MPG going to Mongo's in sept of 22. Propane was about 2.41$ a gollon (with motor fuel road tax on it,gasoline close to or double that) had a/c on full time. I don't think propane verses gasoline economy is quite double but close. Right now propane equipment salesmen want you to use their equipment and just fill up at any propane source well they are all expensive ! A big chunk of my propane economy is buying propane at the right time,you then have to store it,pump it,hold it in hot weather (hi pressure) and don't get hurt with it. Now since I heat with it too it is here full time anyway. My local full service propane dealer is a pal of mine and knows I can safely handle the fuel that is an advantage. I depended on him early on for fill ups and he even still offers a break on motor fuel fill ups. Even so it is still best to buy at the right time and in these hard times know you have fuel handy. I have become a propane tank specialist by learning how to prepare them for long term storage,still have some 76 cent propane out there,however modern prices dilute that. Some one commented earlier about using those trouble-making liquid fuel expensive carburetors I don't use those nor fuel pumps nor wet filters. No sludge,easy starts,never cold natured,oil stays new,easy to trouble-shoot,buy any part new internet. At swap meets often buy propane stuff cheap because no one recognizes it,so there you go.

Otto Friends have called me Hank LOL but they know where to come for propane advice,domestic and vehicle use !! Hank Hill could have a new lease on life if he would do episodes on truck motor fuel propane. It took me 10 years to get a pal to try LPG on his s-10 now he just runs the wheels off of it like I do. I watch full time for propane vehicle accidents and if you follow the guidelines it is safer than gasoline. Those tanks are made to stand a crash,and mostly once the dust settles the fire fighters will get it out of the ditch and throw it in the truck bed with the propane still in it.

Starting new thread.

This will start it or end it.

If you are looking for performance, Propane is not for you, unless you are injecting it along with other power adders.

True story: Back in the mid ‘90s I was assigned by my Chief and the City Manager to assist Oklahoma Natural Gas with a testing program for using various alternative fuels. ONG would supply all the equipment and fuel and provide mechanics to help the City’s own mechanics install it. We picked the newest police car we had and converted it to propane, 350ci police intercepter engine, Chevrolet. I was to then take it and drive it for a full 8 hour shift, including a stint at our high speed pursuit training track. The results were very disappointing. Normal driving was ok, a bit gutless, but ok. Pursuit driving I could have been outrun by a VW with a good driver. There was a switch installed in the auxiliary panel that switched back to regular gas. Pedal to the floor on propane then flip the switch. It was like hitting the nitrous button.
Test #2; everything was installed to run on CNG. Exactly the same tests were performed. Normal driving was ok, a bit more gutless than propane. But still ok. Pursuit driving for the first 200 feet I could be outrun by a 12yo on a bicycle. Flip back to gas and hang on.
If we never had to use the full potential of the engine, either propane or CNG would be fine but sometimes you just gotta go. Cost savings would factor out at about 8 months to pay for conversion not counting the cost of a refueling station. This was with the grant from OGE if we went with CNG.
Needless to say the City chose not to change their program and still uses gasoline to this day.

Now back to the practical world, if you have the access to propane and the expertise to install the equipment and maintain it then maybe it would be for you. Cleaner oil between changes, probably. Easier starting, maybe. Cheaper fuel, certainly.

This is my personal opinion based upon my personal experience. FYI

Pretty much mirrors my experiences, except you obviously didn't leave the propane in place long enough to experience engine failure.

Jon

Back in the '70s I was thinking about propane. A trusted source told me it's great for running around town like taxis and delivery vehicles do but if I was serious I would have to look at changing the camshaft; propane burns at a different rate than gas. I lost interest.

I found this discussion: https://fuelsforum.rasoenterprises.com/viewtopic.php?t=1708

Nashville Tennessee runs a fleet of small shuttle buses for senior citizens on CNG. Most likely subsidized by some sort of pork barrel federal grant, I'm pretty sure. The regular city bus system still runs on Diesel power. I maintained a bunch of vehicles for a sand and gravel and concrete business in Merced California back in the late 1970's, but the systems were old and badly worn because the cheapskate owner of the company never threw anything away. We used to call the junk heap out behind the maintenance shop the "parts department"! I'm a little bit old and feeble now, but I think I could still outrun anybody who wanted to GIVE me a LPG fuel system!
Jerry

Jerry - I think that "pork barrel" you referred to was responsible for a lot of local districts converting to propane (green energy) buses maybe 40 years ago; and subsequently raising taxes across the area to pay for new engines for all the buses after all the engines blew up.

When I moved here some 50 plus years ago, the local propane company used propane in their local (15 mile radius from the shop) delivery trucks. Some 40 years ago they converted to gasoline. If propane is not cost-effective for a propane supplier..........................................

There were a lot of local systems the school districts could not give away, that got recycled.

Jon.

I used to maintain a fleet of step vans that the co. converted to propane against my advice. These college grads "engineers" in their plush offices know more then a grubby old mechanic. It ate up the valve seats on the 300 cid Fords. The 292 chevs. seemed to do ok. The drivers hated fueling-up. If they ran out of fuel they had to be towed in. (the same thing is going to happen with electric vehicles). They finally went back to gasoline.

George

Since LP gas (and possibly CNG) has a very high anti-knock rating (around 110 octane) engines that run that kind of fuel need around 12:1 compression to get the full benefit from using it. The exhaust valve seats also need to be made of a hard material like Stellite to avoid erosion of the seat due to the "dry" fuel. Once an engine is modified that way, running gasoline, even temporarily, isn't an option. Some farm tractor engines were purpose-built to run on LP, but I haven't seen a new one set up that way in over 30 years. Diesel is a much better option, in my decidedly biased opinion. "Your mileage may vary"!
Jerry

Martin You know it's common knowledge among vapor fuel users that natural gas is not very satisfactory. My 04 GMC propane injected 4.8 1/2 ton runs on the interstate at 80 MPH no problem. Can't tell it from gasoline.

Gord&Fran You wont have to change cams to use propane, all of my coversions 51 216 20 years,51 6400 6 years,16 horse kohler weldor,2-8 horse Briggs wood splitters 6 years,and several other "parts engines all have the same cam they came with. the biggest drawback is low compression and soft valves.

I've been involved in the design and installation of a number of Natural Gas fired standby generators for various facilities. They are piped directly to the NG distribution system. I have not heard of a failure from one of them, but of course they get little run time, mainly monthly test runs and the very infrequent power outage. I believe they used Chevy V8 engines appropriately modified, and have no provisions to switch to gasoline, although a couple also have an LPG tank and automatic switchover system if the NG system experiences an outage. They do the job they were designed to do.

I work at the local school district and maintain 170 school buses, 130 of which are dedicated CNG, plus 40 CNG truck and maintenance vans.

80 Thomas built HDX buses with the 8.9L CNG
30 Thomas Built C-2 buses with the 6.7L CNG
20 Chevrolet G4500 with 6.0L CNG
40 Ford vans and trucks with 6.2L and small V6's CNG
40 Thomas built C-2 diesel, DEF issues but no real engine troubles.

2013 8.9L is garbage, melted pistons, bad sensors, bad computers, bad fuel systems. most over 90000 miles
2015 and up 6.7L is OK, runs Ok, not much trouble. 60000 and up on miles
2014 6.0L Chevrolet OK other then valve seats and O2s going out, most over 100000
2013 and up Fords don't run may miles, but no real problems with CNG.

We have changed out 6 sets of the Chevy heads due to valve seat failures, these were conversions done to standard engines. But we also have changed out as many camshafts due to lifter wear, so the engines problems are not all CNG related.

The district is shopping for new buses due to fleet age and miles, so we are going back to diesels. Thomas Bus, our main suppliers hasn't sold a CNG bus is three years in our area, the demand is just not there. CNG parts are expensive and hard to come buy and getting them worked on under warranty is tough, no one wants them in their garage for fear of a leak. We have two or more a day with check engine lights and / or service calls for low or no power. Spark plugs are $110 each, every 15000 miles times 110 buses, the Chevrolets use standard off the shelf parts. Computers, $2000, Ignition control Module, $1700, 18" long flexible fuel line $800 ( five per bus ) 10' long flex line $1000, fuel tanks, $15000 to $18000 each.

Lets not forget about the mileage, 300 miles for the 8.9L if you run it till it quits, 6.7 will go about 500 miles, the Chevrolet, about 5 miles per gallon equivalent to gasoline.

Our white fleet of maintenance trucks are bi-fuel or full CNG, all Ford 6.2L engines and all getting about 5-6 miles per gallon.

The district started this in 2013, so for 10 years I have had to deal with this stuff. I am a certified tank inspector along with ASE certified alternatives fuel mechanic. I hope you guys running Propane have better luck then we have had. I'am sticking with gasoline!

Atlanta's city buses run on CNG, and have been for a long time. Regular routes, no need for performance, etc. Seems to be ok for them.

WEbOLD Those are interesting charts you posted there.My propane injection installer told me when gasoline goes up he starts getting calls for new lpg systems. So far my system put on in 2013 has been fine,not totally trouble-free. About 70,000 miles so far,has not let me down,of course you can easily switch right back over to gasoline.

Propane(higher CR) pistons used to be available for GM 292 engines!

Ed

Joe H You know they knew clear back in the fifties that valve seats had to be dealt with to run vapor type fuels. Induction hardened GM valve seats with modern high quality valves work fine. Once the seats are ground it's over gotta have seat rings on engines that are really loaded and working hard. As I have said before on a light weight,around town pickup truck it will run quite a while with what is in there. My 235 51 6400 is coming up on 12,000 miles that way. I called Goodsons and bought valve seats put em in a 235 re-build,later called for more he said oh don't use those for propane,well they have run over 12 years now so go figure. Apparantly no-lead seats will work too !

Ed Pruss Remember how those 292 engines would shudder?? That was from high compression that would be a plus with propane. Those heads would warp both ways like a chunk of stove wood,have to be cut on both surfaces.

We knew from the start there was going to be seat trouble in the Chevrolets, the company that converted them didn't want to scare away business so they said it would not be a problem. If you needed hardened seats, they couldn't convert any old thing that came in the door as cheaply as they could. We've been pretty lucky with the amount of miles they run and idle time school buses get.

Ok Gang .... After further research and input from an adhoc technical committee, we thought it necessary to definitively go on the record with a Stovebolt.com statement to make clear our stance on this modification -- especially for those researching this thread in the future.

We at Stovebolt.com do NOT recommend this modification for the amateur antique truck restorer/owner/enthusiast.

Whether or not propane, as a fuel, is reliable and efficient is arguable and beside the bigger issue.

Despite how complacent we may be from safely using our propane stoves and BBQ grills, the fact remains that propane is dangerous!

Why? Because it is not visible, and heavier than air. Improper installation can lead to a variety of issues, not the least of which is a leak. A leak will spill invisibly onto the ground, where it will spread until it finds ignition. Even before that, in an enclosed space, it could suffocate someone working under the truck.

Thus, a propane installation, if it must be done, SHOULD be done by a trained and certified *professional.* We can not in good conscience recommend the use of propane to the average enthusiast.

Thanks,
John