Yet another "fact" gathering question that a search here turned up nothing :(

Anyways, I am curious about the benefits/disadvantages of each type of injection. Obviously diesel and propane have the same benefits as EFI in terms of running at "any" angle.

From my understanding, diesels don't like to rev and thus require an overdrive of some sort in order to be "usable" on the freeways. But they are cool running. They also weigh a shit load. They have no vacumn so power brakes need a vacumn pump or hydroboost assist. In CA, this conversion makes one smog exempt. Is this correct? Do they require anything special in terms of fuel tanks? Or will any tank that works for gas work for diesels? Does the engine run cleaner(in terms of oil contamination)?

From my understanding, propane uses a regular gas powered block with no special requirements. It does run hotter. It requires a special tank. It actually is "delivered" to the engine in a gassious state. It requires a significant advance of the timing. Dual fuel provisions are available but not really worth the effort or time due to piss poor performance for both systems. Is this correct? How much warmer than a standard gas engine does it run? Does the engine run cleaner(in terms of oil contamination)? Does a conversion to propane(not dual fuel) make a vehicle CA smog exempt?

Did I miss something that would make a huge difference?

TIA for ANY usefull information,
John

I can't help at all about smog laws. I've never even seen a smog-Nazi.

Propane runs 5-25 degrees warmer then gas on average. You should block off the exhaust crossover in the intake manifold (If you have one) They run quite clean from the oil point of view.

diesels generally need additional cooling to perform well. They DO cool down while idling, which is handy. Average is 250-700 lbs over a comparable gas motor. Max revs depend on the motor, anywhere from 2200rpm to 3600 rpm. The torque curve lets you get away with numerically lower gears, which helps negate the lower redline. Diesels are harder on oil than gas or propane, but much easier on fuel. Maintnence requires no special skills, but extensive motor work should be done under the guidence of a pro. A couple other advantages to diesels in trail rigs are: No ignition to drown out. A tight diesel can literaly run underwater: this also means that charging troubles won't sideline you. As long as you don't stall and don't need the radio or winch, you can run w/o a battery.


I say go RUDY.

I think diesels and LP motors have a major coolness factor to them. Perhaps I think that because my rig has yet to get any real cool points at all in my eyes. Anyhoo, I have been told that once you put gas in a tank, you should never use it as a diesel tank because of some reaction that I am still not clear on :p If you are a tree hugger, propane burns much cleaner than gas or diesel so that would be a plus. I think overall, propane is just damn cool IMO :rolleyes:

Originally posted by The Mick

Propane runs 5-25 degrees warmer then gas on average. You should block off the exhaust crossover in the intake manifold (If you have one) They run quite clean from the oil point of view.


I was always told that propane ran cooler, where did you find that it runns warmer, and what is the point of blocking the exhaust cross over???

Thanks

Ian-

44Runner, you mention not to use diesel in a tank that has had gas in it before... however, is there anything special about a "diesel" fuel tank?

Hopefully I wasn't being misleading when I mentioned the tank as if I did a diesel conversion, the tank would also get replaced.... but my curiousity about gas vs diesel fuel tanks stems from the question of "would I be able to buy a new stock fuel tank for my vehicle and use it with diesel":p

the fuel tank is the LEAST of one's concerns in a diesel conversion. Just drain it thoroughly and fill it up with diesel. A little gasoline mixed with diesel won't hurt anything. You are supposed to avoid zinc with diesel so a Grignard reaction won't happen (Zn + aromatic hydrocarbons = crud).
Charlie

I had a dual fuel 2001 F-450. It ran Ice cold on propane. It ran like shit but Ice cold. I think the exhuast might have been hotter. but not totaly sure.

Anyways it ran cooler on propane than gas.

Originally posted by KrustyKruiser


I was always told that propane ran cooler, where did you find that it runns warmer, and what is the point of blocking the exhaust cross over???

Thanks

Ian-

The fuel is already atomized and a hot intake manifold just kills the power. More BTU's in propane , that = more heat and a gas vapor doesn't carry off heat like a liquid vapor.

Originally posted by Old Scout


The fuel is already atomized and a hot intake manifold just kills the power. More BTU's in propane , that = more heat and a gas vapor doesn't carry off heat like a liquid vapor.

Everything I have seen says gas has more BTU's thats why you see a power loss when going to propane

Originally posted by Old Scout


The fuel is already atomized and a hot intake manifold just kills the power. More BTU's in propane , that = more heat and a gas vapor doesn't carry off heat like a liquid vapor.

How would i find our if my intake has one?

Thanks

Ian-

Originally posted by KrustyKruiser


How would i find our if my intake has one?

Thanks

Ian-
What are you running?????????
2F, SBC????

95 % of all engines are using a exhaust heated intake. Blocked gaskets are usally the the quick and dirty away of cooling it off.

I have a 1957 Allis Chalmers WD-45 tractor that I have run on propane with a turbocharger for nearly 30 years.

Propane has a lower BTU rating than gasoline and it won't make near as much power, thus the turbo. Even with the turbo the engine water temp runs @ 15 degrees cooler than gas. The exhaust temp though, is MUCH higher. It's static comp ratio is 10.6:1 and I have the wastegate set at 16 lbs boost which more than makes up for the lower BTU rating. I have run as much as 30 lbs with no detonation, but it burns the exhaust valves.

I change the oil every 50 hours or 3 months. The old oil is as clear as the new. The rings have been in that engine since '73 when I installed the high comp pistons and turbo.

I got the info and the turbo for the conversion from Ak Miller. He used to do lots of racing in SoCal in the 50s and 60s. He used to sell propane/turbo kits and had at least 2 books out on the subject. Don't know if they are still in print or not.

Scouter 5.7 Your right about the BTUs being lower. The reason that gas runs cooler is it by-products of combustion .

Combustion is also that process which converts the potential energy of fuels into kinetic energy (heat and light). Most fuels (gasoline, diesel oil, propane, etc.) are compounds comprised primarily of carbon and hydrogen. These hydrocarbons represent an excellent source of potential energy which is released as heat during the combustion process. A common example is the oxidation of propane, the fuel used for gas ranges:

C3H8 + 5 O2 -----> 3 H2O + CO2 + Heat
As propane burns in air, its carbon atoms are oxidized when they combine with oxygen to form carbon dioxide. In turn, molecular oxygen is reduced by the hydrogen atoms, forming water. The heat produced can be used directly such as in the cooking of foods or to cause the expansion of the gaseous products produced to perform mechanical work such as in an internal combustion or steam engine.

Many other substances besides hydrocarbons can be used as fuels. For example, the alcohols, such as methanol (CH3OH) and ethanol (CH3CH2OH) are often used in racing cars. Ethanol mixed with gasoline, called gasohol , is currently being explored as a substitute for gasoline. Among the simplest fuels is molecular hydrogen (H2) which readily reacts with oxygen forming water as shown:

2 H2 + O2 ------> 2 H2O + Energy

Propane is (C3H8) and Gasoline is ( C8H15-18) There is more hydrogen in gas to create more water vapor, More water = cooler running engine.