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Tech: Propane conversion

Discussion in 'The Hokey Ass Message Board' started by sgtlethargic, Aug 6, 2006.

  1. Propane Conversion Basics
    Kurt Anderson
    8/6/06

    1. Resources
    1.1. Book: The book to get is “Propane Fuel Conversions” by Jay Storer. It’s out of print, ISBN 0-931472-12-1, published by S-A Design, 1986. This book is the only one like it I’ve seen. It’s got a lot of good information, a little misinformation, and a few holes if you’re using it to convert a car. Find it on amazon.com, ebay, at used book stores, the library, etc.
    1.2. Components: Not as easy to find, but MM (was OHG, Ak Miller) are supposed to be the better ones. Marilyn Miller still has a shop in Pico Rivera, CA. Impco doesn’t seem to like to sell to individuals, but their stuff is most common.
    1.3. Other components: Gann Products (gannproducts.com) in Downey, CA has adapters, hoses, fittings, etc.
    2. Reasons
    2.1. Cleaner
    2.1.1. Several advantages to this, the main one for this forum may be that the oil/engine are less contaminated with metal-wearing carbon so your engine should last a lot longer.
    2.1.2. 100+ octane, but the rating goes down as engine speed increases from what i get from the book.
    2.1.3. Cheaper than gasoline: If you buy from a distibutor, it seems to be about 50 cents less per gallon.
    2.1.4. Others: Easy to convert, carbs are simple and can be oriented any way, it seems multiple carbs would be easier to tune, supposed to make 4 and 6-bangers run more smoothly, and works well with turbochargers! Before you say non-traditional, I read in “Gasser Wars” that the Mallicoat brothers used twin turbos in ’65. Ak Miller (R.I.P.) used propane and turbos for a long time.
    3. Components
    3.1. Tank: Get a tank made for road vehicles, and buy it used for a lot less. The tank shouldn’t rust inside unless it’s completely empty of propane. Get as big as you can fit fur better range. The tanks are marked for water content (WC); they are filled to 80% with propane. No fuel pump necessary.
    3.2. Shutoff: Vacuum or electric, this is a valve (and filter) for the liquid propane coming from the tank.
    3.3. Regulator (convertor): This converts the propane from liquid to gas, and therefore requires heating it with the coolant system.
    3.4. Carb (mixer): Air valve, diaphragm, venturi, and combination types are much simpler than gasoline carbs.
    3.5. Hoses/Fittings: Get the proper hoses and fittings for the pressure/media. Basically there are liquid hoses and vapor hoses.
    4. Most important things
    4.1. Ignition: Because of 2.1.2. the initial timing can be advanced, but the overall timing should be less. You’re supposed to upgrade the ignition, also.
    4.2. Valve seats: Same deal as unleaded gasoline.
    4.3. Don’t heat the intake, and you can run a cooler thermostat (as low as 160 °F).

    4.4 Biggest disadvantage is refueling- you have to plan ahead.

    Attached pictures
    • Impco 425 and 225 carbs and vacuum shutoff (lockoff).
    • MM X-450 carb with bonnet for pressurizing with a turbo.
    • MM X-1 convertor and electric shutoff (not shown).
    • 22-gal (water content * .80) = 17.6-gallon tank.
    • 27.2-gal (water content * .80) = 22.2-gallon manifolded tank.
    • Impco Model E regulator/convertor

    PS: Propane tanks in the trunk need to be installed legally, unlike shown in the pictures. Basically, a tank hose/valve leak needs to be plumbed outside of the trunk so propane won't go into the passenger compartment. The easier way would be to convert a pickup and put the tank in or under the bed.
     

    Attached Files:

  2. taskforceranger506
    Joined: May 22, 2006
    Posts: 291

    taskforceranger506
    Member

    Great info there....I have a 1954 331 Chrysler Industrail that is sweet clean inside. Thought about converting her over to stick in my '55 Dodge. I can use this info..WONDER what people would think if I rolled into a parking lot car show with a propane ride? Cool? My 1999 FORD SD F-250 POWERSTROKER HAS PROPANE ATTACHMENT, Will out run most Mustangs ...from a stand still. Ran 13.75 in the 1/4. Great sleeper for sure. Like to seet the faces afterwards at the end of a run.:D :eek: :eek: :eek: Slip to prove it.
     
  3. lakes modified
    Joined: Dec 2, 2001
    Posts: 1,283

    lakes modified
    Member Emeritus

    Been there and still doing that for over 25 yrs. with my big block powered 72 merc pickup & my 351w powered 48 merc coupe.
     
  4. Bigcheese327
    Joined: Sep 16, 2001
    Posts: 6,691

    Bigcheese327
    Member

    Bump for reconsideration and to request that you add a link to this article in the "Alternative Energy" social group.

    -Dave
     

  5. dentisaurus
    Joined: Dec 11, 2006
    Posts: 388

    dentisaurus
    Member
    from Boston

    Sadly I believe it's illegal to convert to Propane for a street driven vehicle in MA. The State has it's undies in a bunch about people using any fuel they can't easily tax. Same problem with running veggie oil, folk do it but you can be fined and have your vehicle confiscated and crushed!
     
  6. 84imsa
    Joined: May 24, 2010
    Posts: 2

    84imsa
    Member

    They're phasing in E10 methanol/gasoline here in the Philippines. So far, they haven't blended the super premiums but that's due in about a year. My research tells me that older cars with fuel systems and engines not designed for ethanol will likely suffer multiple ill effects from the gasohol.

    For that reason, I've decided to gradually convert most of my vehicles to run on propane. The Firebirds can run on Avgas (with lots of lead.) :)
     
  7. Bigcheese327
    Joined: Sep 16, 2001
    Posts: 6,691

    Bigcheese327
    Member

    We've had E10 in Michigan for years, and I've never had a bad experience yet. My dad swears by the stuff for his LT-1 Corvette.

    E15 is supposedly on its way soon, and I'm not losing any sleep over it. The pieces that were vulnerable to alcohol were mostly already gone anyway by the time ethanol replaced MTBE here.

    -Dave
     
  8. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109

    scottybaccus
    Member


    Gotta call BS on this. They have the means and process for taxation and refund.

    http://www.mass.gov/?pageID=dorterm...ess_taxguide_fuels_motorfuelsexcise&csid=Ador
     
  9. I gotta agree with Scotty on this one. I did propane conversions and sold fuel for a number of years. Most retailers don't have "pay at the pump" because propane filling is supposed to be attended anyway. Whenever we filled a motor fuel tank, we'd mark "motor fuel" on the ticket and the tax was added on in the office.
     
  10. I had a Chevy Van that was Propane powered for years. Upside was spark plugs and Oil stayed clean forever and the fuel was about 50 cents a gallon - this was in the 80's when gas was about 1.50.
    Downside, loss of power, hard to find stations that sold it.
    In California there are two types of Propane stations, those that sell it for BBQ's and motorhome appliances and those that sell it for Highway use. They claim the highway use fuel is cleaner but my dealer told me it was merely a road tax issue. It is illegal for the BBQ bottle re fillers to sell it for road use, with very heavy fines. More than once I had to lie or threaten a station in order to get some fuel so I could get on down the road. I had two tanks in the van and carried 57 gallons!
    The guy I sold it to eventually threw a rod (after 200,000+ miles). He never changed the oil after I sold it to him because he said it always looked clean!
     
  11. The fuel is absolutely the same, and any dealer "can" sell it. Many retailers near campgrounds, etc. that don't get much motor fuel business just done't want to have to deal with filling out the forms and sending the check to the State Borad of Equalization or whatever it is. The only part that is illegal is filling a motor fuel tank and not reporting it as motor fuel. It's not like diesel where it's dyed 2 different colors.

    I got around that by having my house tank fitted with a "wet line"...for filling my barbeque tank, of course...;)
     
  12. big creep
    Joined: Feb 5, 2008
    Posts: 2,945

    big creep
    Member

    if thats true its bullshit what the state will do to make a buck! unreal! ive been told that you get no carbon build up with cng. but you do loose top end power? i would do it , but just for my work truck.

     
  13. 50stude p/u
    Joined: Jul 14, 2009
    Posts: 169

    50stude p/u
    Member

    Ah great, now I really want to run on propane
     
  14. ken1939
    Joined: Jul 5, 2008
    Posts: 1,558

    ken1939

    They key is the largest tank you can carry. The btus of propane for example are less than gasoline, so your mileage may be about 20 to 30% less than gas. However, if you buy the propane in bulk, meanig you fill up a 32 gallon tank, your cost goes down. Most Uhauls sell propane this way.

    I wanted to convert my Focus to it, and have dual fuel, its about $1500 from a kit from canada, the only downside for me was cutting into the wire harness to be able to have the brain box take over when you switched from gas to propane. That scared me a little, and gas went down in price.

    I do want to build a rod with that as the fuel though, cool deal.
     
  15. uglydog56
    Joined: Apr 8, 2008
    Posts: 331

    uglydog56
    Member

    Also every flying J has propane for sale, but usually it's kinda high. However, at night it can get you out of a jam.
     
  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 17,903

    gimpyshotrods
    ALLIANCE MEMBER

    True, but if you are building an engine to run propane as the only fuel, you can run a much higher compression ratio, or a higher boost level from a turbo or supercharger.

    The octane rating of Propane is around 110. Bump your compression to to take advantage of that, and you will see most of that power/mileage loss come right back.
     
  17. BuiltFerComfort
    Joined: Jan 24, 2007
    Posts: 1,620

    BuiltFerComfort
    Member

    I used to go up a certain big hill in a stock Datsun mini pickup - the hill taxed the motor but it went up at highway speeds. One day I rode with a guy who had a similar truck running propane and by the top of the hill we were in first gear, slogging along with the overloaded diesels in the extra slow lane. So yes, power is a big issue. Decent 0-60 times are needed even for a daily driver, as a matter of road safety.

    But I liked reading about the turbos...
     
  18. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109

    scottybaccus
    Member

    There is a very simple reason for the power loss and it has nothing to do with the fuel, but with how it is delivered. On a gas carb, the air goes in the top and the fuel joins mid stream, taking up almost no space as an atomized liquid. When you use an LPG fogger, it sits on top of the gas carb. Now the air AND fuel need to pass through the same pathway. LPG is a gaseous fuel having a volume displacement much higher than the gasoline, so less air will now accompany the fuel through that passage way. This reduces a 600 cfm carb (rated on airflow) to be maybe 400 cfm of air with the appropriate amount of fuel to match. That's very old technology.
    Today, you toss the carb altogether. It is replaced with a Mixer, a dedicated LPG carb that mixes the right ratio of LPG and air through a passage that passes maybe 475 cfm, but now the fuel is added below. Use one of these and the engine is back to flowing more air and power is on par with gasoline. Optimize the spark curve, compression and cam profile for LPG and you can exceed gasoline power.
    Now when you line up against a propane car, just ask if he is dual fuel or dedicated lpg. If dual fuel, you can take him.
     
  19. '46SuperDeluxe
    Joined: Apr 26, 2009
    Posts: 255

    '46SuperDeluxe
    Member
    from Clovis, CA

    The guy from "Mother's" polish built a bitch'in ride called "Pro Pain" or some such. The fuel is 103 octane, but because of lower BTU's the old typical conversion you would loose something. This can be offset by upping the compression to 13:1 and LPI liquid propane injection. The fuel expands to a remarkable degree as it is injected near the ports and you get a bit of boost although naturally aspirated (some cooling of the charge too). There is a company down under that makes these rad muli chambered extruded aluminum tanks that fit your application better than the usual steel tank in the bed, farm truck idea. Roush has been on it also, they are racing a car with it now. They also do conversions. You have to be a licensed tech to do them, and from my checking things are hinkey about a guy putting it in his own car in Cali as usual.
     
  20. stude_trucks
    Joined: Sep 13, 2007
    Posts: 4,755

    stude_trucks
    Member

    Wasn't converted properly, read above comment from Gimpy and that will explain it to you.

    But put very simply, propane is not gasoline and the fuels don't burn the same. Run a motor optimized for gasoline on propane, it will run like crap as you have experienced. Run a motor optimized for propane on gasoline and it likely won't run very well, it at all, before you grenade it from pre-detonation.

    Optimize a motor to run on propane, it run very well with little or no performance drop.

    Propane conversions on older carb. motors with no emissions or electronic crap is actually very easy and simple to do. Get a little more tricky with shaved heads or higher compression pistons, super chargers, etc. and the sky is the limit just as with gasoline.

    Plus, contrary to what might seem the case, propane is actually safer than gasoline. It is harder to combust and if leaks it just vaporizes and dissipates very quickly and becomes harmless for the most part unless confined in a space at a very specific range of % to oxygen.
     
  21. burtrido
    Joined: Mar 4, 2001
    Posts: 232

    burtrido
    Member

    Are you talking about the company called "GAS RESEARCH"
    I know that they make a bit of high performance LPG stuff.
     
  22. '46SuperDeluxe
    Joined: Apr 26, 2009
    Posts: 255

    '46SuperDeluxe
    Member
    from Clovis, CA

    The company that extrudes the modern tanks is Propane Performance Industries
    http://www.ppidts.com/

    The engine in the Mother's "Pro Pane" Chevelle runs about 1000hp and was built by Haigh in Australia or New Zealand. They are more advanced on this s#!+ than we are up here. As much talk as the administration talks about clean air and not being dependent on foreign oil (we have LPG out the wazoo) it sure looks like a major roadblock getting it into the hands of rodders.
     
  23. dentisaurus
    Joined: Dec 11, 2006
    Posts: 388

    dentisaurus
    Member
    from Boston

    Not BS I,m afraid. Yes you can use Propane in a vehicle for off road use but you can not change the fuel used in a vehicle from that which the manufacturer of the vehicle used if the vehicle has to pass emissions. Depending on the type of title your vehicle has you may or may not have to pass emissions tests. I wanted to convert an off topic pick up to diesel, but because that model of truck was never sold in the US with a diesel motor the RMV said that this was not legal. If they BSed me I am all ears.
     
  24. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109

    scottybaccus
    Member


    Well, you are mixing topics now. First you said they disallowed conversions on tax reasons, now you are saying they don't allow fuel conversions. I covered the first already and it only took 10 minutes to find another clue in your states own web site. Look HERE, at the bottom of the page, Mass.gov states...

    "Guidelines for Alternative Fuel Conversion [U.S. Environmental Protection Agency (EPA)]

    Cars and light truck owners interested in changing their vehicle’s fuel type must follow the EPA's certification procedures to avoid tampering violations."

    Do your homework. Make the person telling you no show you the law. Go find the state's legislation on vehicle fuels and registrations and lay it all out side by side and read it. Hear-say is a bad thing. I got the run around in TX for a while, too, so I took matters into my own hands and found out that TX doesn't even regulate it. The U.S. DOT regulates the parts used on-road and the commercial installers, but individuals can DIY to their heart's content.
     
  25. Spanielrage
    Joined: Jun 11, 2010
    Posts: 3

    Spanielrage
    Member

    Let me see if I can contribute some knowledge here. Joined HAMB for info on restoring my wife's grandfather's narrowed and shortened T (with an A 4-banger and tranny) and rodding his propane-powered '52 Ford 1-ton. Her grandfather owned an LPG distributorship in Texas from the late '40's to late '70's and he's shared his knowledge and sometimes bad experiences converting gasoline engines for vehicles and irrigation engines over the years.

    First, know your fuel. The names propane, butane, and LPG are used interchangeably, and work the same 90% of the time. However, LPG is what is typically sold, which is a mix of propane and butane, with the mix depending on season and location. The farmboys reading this know how bad butane can be to start in the winter (JD 730 for me), so if you last filled in summer and it's gotten cold, have your jumper cables handy. Ether works on vaporizers, and the modern computer-controlled dual-fuel vapor units start on gasoline before switching to LPG, and some liquid-injection units heat the injectors (wait time like old diesel with glow plugs). A goofy thing about LPG is that it has more BTU per pound than gasoline, but has less density per gallon, which means more gallons of LPG are needed.

    LPG tanks are safer, but have to be periodically recertified for a reason, and on-road tanks have to be permanently installed (rockcrawlers and drag racers can get away with forklift tanks). When installed in trunks, tanks must be vented to exterior. My homeowner's policy won't let me store a LPG-fueled vehicle in my attached garage, as an overfill or house fire heating and pressurizing the tank would vent fuel into an enclosed space.

    For old engines, watch your valves and seats. Gaseous fuels are "dry" and don't lubricate valves. Unleaded engines will still wear quicker with LPG than gasoline. Blow-by is another killer on these engines. Make sure the rings are sealing good and the crankcase is well-ventilated. Loose tolerances on engines until the high-compression era killed many conversions. On vaporizers, backfire can be a problem, especially on poorly tuned engines and startup, so consider a flame arrestor or covered air cleaner. Lean-out on inliners isn't as much of a problem as it is with gasoline, as gaseous fuel atomizes and mixes better, but the fuel has to be up to temp on vaporizers, which is usually done with a line off the water pump. I was told the '52 Ford actually picked up power after the conversion, which I would guess is the result of better mixture and the timing advanced.
     
  26. carbking
    Joined: Dec 20, 2008
    Posts: 2,957

    carbking
    Member

    Before you make up your mind that using LPG is truly less expensive than gasoline, make a couple of calls to your local LPG dealer and ask what fuel they are using to power their delivery trucks.

    As far as comments that LPG is safer than gasoline; LPG is HEAVIER than air. Leaks simply spread along the ground until they find combustion. Gasoline evaporates and becomes lighter than air.

    Jon.
     
  27. Spanielrage
    Joined: Jun 11, 2010
    Posts: 3

    Spanielrage
    Member

    Most use diesel, but only because the 2 1/2 and 3 ton trucks they deliver with no longer come with gasoline engines that can be easily converted. The GM 8.1 big block was the most popular delivery truck, but the medium duty truck and engine are both discontinued.

    Regarding price, local price for LPG today is $1.79/gallon (without road tax, which is collected in by an annual stamp in Texas) vs. $2.46 for gasoline. You'll be hard-pressed to cover your conversion costs and the refilling can be a pain. The real advantage for hot rodders is that LPG won't go bad like like gasoline (especially since the introduction of ethanol) and you won't have carbon and varnish issues, plus it's more forgiving (within reason) of high compression and aggressive cams.
     
  28. stude_trucks
    Joined: Sep 13, 2007
    Posts: 4,755

    stude_trucks
    Member

    I'll take note of that next time I'm playing with gasoline.

     
  29. gimpyshotrods
    Joined: May 20, 2009
    Posts: 17,903

    gimpyshotrods
    ALLIANCE MEMBER

    CNG. They are using Compressed Natural Gas in great numbers out here. All of the big local fleets have a portion, if not their whole fleet running on CNG.

    All of our wast haulers here use CNG. A whole ton of the taxi cab companies do too.

    Next time you are out driving, look for the little blue diamond. You might be surprised how many you see.
     
  30. Richard/SIA
    Joined: Mar 22, 2010
    Posts: 246

    Richard/SIA
    Member
    from No. Nevada

    I have a 1984 Chevy C10 4x4 running on Propane.

    Got it cheap because no one else would make an offer on it.
    Pretty clean and everything but the radio works, too bad the paint is flaking.
    Rebuilt 305 engine, manual trans, stock size tires, slow as molasses in January!

    I used to have a propane powered Jeep Station Wagon, so I knew what I was getting into, but needed a cheap 4x4 ASAP.

    The truck was converted by a guy who worked for a propane company, so I guess he was not paying the $3.50 a gallon for fuel that I am.
    Currently gasoline would be only $2.85 a gallon, have more power, and increase my mileage.
    Cannot use the truck to tow with, not enough torque, the 305 is not helping with that.

    Builder would have taken the truck to AZ with him, but it was not legal there as a propane only vehicle.
    The daughter he left it with to get rid of said the gasoline tanks were removed to comply with Washoe county ordinances, no smog check on propane only.

    I'm not in Washoe, as soon as I can I will remove the propane unit and go back to gasoline.
    This will double the value of the truck, and the amount of space in the cargo bed.
    Win - Win!

    As it is now, I cannot take the truck on a long trip, not every place that sells propane will fill a vehicle, mileage is terrible, power is low, and if you run out of fuel you have to call a tow truck!

    For all the years Propane has been available as a motor fuel is has never really become popular.

    I know why, from personal and CURRENT experience.

    Propane is fine to "make a statement" :p or take advantage of if you have a source for free fuel, but is NOT suitable for most of us in the real world.

    Think carefully before investing in a conversion!
     

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