Gas motors:

Grandpa's old coal truck was gas. 302 gas Ford. Yeah, I know, that's small and weak, but the dadgum thing hauled 20 ton of coal around 5 days a week for over 20 years and has a wrecker bed on it now, still in operation.

He went through 2 sets of heads and 1 block in right at a million miles.

Power? The truck was an F700 with a tandem under it, 10 speed and loaded might pull a hill at 30 mph if it wasn't too steep. Divebomb (I-75 around the 51 MM in Kentucky) it wouldn't hold 25 mph. Kinda felt like you could jump out and run along beside or just lift up the old stopsign in the floorboard, stick your feet down and give it the Fred Flinstone.

Seriously, I don't believe you could efficiently make gasoline run in diesel fashion without ignition/spark plugs, etc. For one thing, while gasoline has a higher flash point, it generates less BTU's and thus less power for the same amount of fuel. Gasoline burns up way to quickly where diesel is a much slower burn. Gasoline's power would come extremely fast and not hang on like diesel would. It's kind of the same principal as converting a heating boiler from coal to gas. The coal takes longer to get burning, but once it does, it burns much longer giving off more heat from less. Natural Gas is instant on and instant off so once the burner runs long enough to build up the steam to the set level and turns off, it begins to cool off immediately. Coal will sit and burn even without the blower on delivering some heat the entire way. I know of one conversion that resulted in some monthly bills with gas nearly as high as an annual coal bill.

Secondly, you wouldn't get the lubrication factor with gasoline that you do with diesel. A lot of what makes a diesel as trouble free for what it is comes from the lubrication the fuel gives to the engine.

Torque and power: Just an observation, I know a big truck is different, but the principal is pretty much the same.

Truck A: Dodge 2500 5.9 Cummins Diesel: Figure about 18 mpg on the highway.

Truck B: Dodge 2500 V10 Gas: Similar horsepower, less torque by about 1/3 and about 13 mpg on the highway.

The RPM bands would be a lot different than diesel forcing redesigns of trannys and rear gears to make the truck operate satisfactorily. Cars don't need the torque of a diesel truck, and most gas engines these days have a decent amount of horsepower, but relatively small amount of torque.

For what it's worth on the car diesels, I have a friend in the 80's who had a diesel Ford Tempo or Taurus, I can't remember which. It had a 3 cylinder Mitsubishi in it pretty similar to what they put in compact tractors. This thing was slow to get up to speed, it's take 3/4 of a mile to get it to 60 mph if running down hill, but it got 60 mpg.

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[It had a 3 cylinder Mitsubishi in it pretty similar to what they put in compact tractors. This thing was slow to get up to speed, it's take 3/4 of a mile to get it to 60 mph if running down hill, but it got 60 mpg.

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#### im gunna stick a 3 banger mitsu in my truck hot dang from 6 mpg to 60mpg .

 

Yeah, going 6 mph!

 

Well I've always thought of Diesel being more efficient. More BTUs compared to gasoline and its generally better all around...even cleaner burning if I believe correctly.

I drove a Uhaul (ugh, nightmares) when I moved from MN to Vegas and went over the rockies on 70. That stupid truck had a v12 ford engine with gas and it just sucked the fuel down with no power whatsoever.

When I moved the next year from Vegas back to MN, we used a 26 foot Diesel Penske truck and it worked great. We went through AZ which is much less hilly, but it worked great on the few hills we did have and you could feel the power.

I think the reason you see all the big heavy machines using diesel is because it is the most efficient fuel we have, at least in terms of power. Trains use em, trucks do as well, lots of pickup trucks, a select few cars...etc.

Also, Im not sure how to word this correctly, but just as diesel produces more BTU than fuel; per gallon, more fuel is used up per gallon than gasoline. What I mean is that...and Im not sure of the actual numbers, but something like 65% of gasoline is actually used and lit up and combusted/providing power compared to 85% or something with diesel.

 

[Secondly, you wouldn't get the lubrication factor with gasoline that you do with diesel. A lot of what makes a diesel as trouble free for what it is comes from the lubrication the fuel gives to the engine.


See if you guys follow me on this. When I was in High School auto shop, the instructor told the class that the worst thing you could ever put in a gasoline engine is gasoline. Take your fingers with some gas on them and rub them together, it'll fell like sandpaper. Diesel is an oil and is an exellent lubricant. Gas is abrasive as he**. Thats why diesels can run for a million or more miles sometimes before rebuild. Try the gas thing with your fingers, it's pretty neat. See Ya

 

Exactly the reason why Gasoline engines are not used. If a rig were gasoline, it would probably get somewhere between 4-5 mpg. This would eat into the saving, and then when summer rolls around and diesel is cheaper, it makes very little sense...

A Diesel engine is about 10-15 % more efficient and diesel has about 10% more energy than gasoline. This gives them about 20% more mpg...

Also, gasoline engines produce more of their peak HP at higher RPMS, meaning that a truck pulling a load would cruise at 3000-5000 RPM causing more wear on the engine and more maintenance.

 

I've driven the Ford 543 CID V8, the Intertrashanal 549 CID V8 and the Mack 707 CID straight 6, the Mack would pass everything except a gas station.
With modern diesels there's no comparison, fuel mileage is measured in miles per gallon, not gallons per mile.

 

Never drove the Ford that I remember but I have driven the 549, and the Mack 707, Not to mention lots of Red Diamond Internationals.

I think that Mack got 3 MPG if it was set up right. Id pulled pretty good for the old gal she was though

 

Honda is supposed to have a top secret direct injection gas motor coming out in the next few years. Would work like a diesel with no ignition system. It is for cars. They have some pretty sharp engineers so I imagine it will be a winner if they can work the bugs out. Who knows, maybe someday they will develop a class 8 gas burner that will perform well and be efficient.