Diesel vs. Gas

Discussion in 'Lawn Mowing' started by jsr2741, Oct 29, 2002.

  1. jsr2741

    jsr2741 LawnSite Senior Member
    Messages: 392

    Does anyone have an opinion on when buying a ztr would you be ahead to buy one with a diesel or gas. I like the idea of more torque, less wear, and general reliability of a diesel but does it make sense to buy a machine were it will wear out long before the engine.

    This was the response I got from my dealer. I've also asked some friends who work in road construction why their company doesn't use diesel powered pickup trucks. Their response was the same; we wear out the truck long before the engine and its just not feasible.

    Any opinions.

  2. Green Pastures

    Green Pastures LawnSite Silver Member
    Messages: 2,457

    Kubota has some nice diesel ZTR's.

  3. sdwally

    sdwally LawnSite Senior Member
    Messages: 386

    If you compared the same size engines diesel's have more torque and usally less hp. Torque is what is need for powering through heavier loads. Turbos on diesels will increase the hp and torque ratings.
    Diesel's are constructed heavier to handle high compression ratios. Gas engines typically operate at 125psi cylinder compression which is about an 8:1 compression ratio. Diesels operate at 300psi to 400psi which is about 32:1 compression ratio. That is why General Motor's first diesel which was gas engine block converted to diesel was a lemon. It could not handle the higher compression pressures.
    Diesel fuel itself also contains much more available potential energy for doing work than the same amount of gasoline. As an example, with no load on the engine, at idle a diesel engine will use a teaspoon of fuel, let say the gas engine will use a teaspoon of fuel also. At no load and at full throttle, gasoline will use a cup of fuel, while the diesel will only use a few drops more than a teaspoon. However under heavy loads the diesel will increase its fuel consumption to about 3/4 of a cup. While the gas engine's fuel consumption under heavy loads stays the same.
    Gasoline engines are constricted basically by the amount of the air/fuel mixture that the engine is able to get into to the cylinder, while diesel engines are only restricted by the amount of air(oxygen) in the cylinder during the ignition phase.
    Diesel fuel is injected into the cylinder at the start of the ignition phase and for a period of rotation of the crank(longer period of fuel burn for more power). While gas engine has a spark to ignite the air/fuel mixture for a bang of power.
    This makes diesel much more fuel economical in the long run. Also with diesel, there is no carb problems to worry about or any changing of plugs, wires, cap, and rotor on a regular basis.
  4. Brickman

    Brickman LawnSite Bronze Member
    Messages: 1,249

    The diesel engine option will cost more $$ to buy. Put pencil to paper to see if it will pay out in fuel savings over the expected life of the unit.

    If I could make the numbers work, diesel would be the way I would go.
  5. LakeSide Lawn and Landscape

    LakeSide Lawn and Landscape LawnSite Senior Member
    Messages: 337

    I think the deisel engines are too expensive on a mower.There are some great things about a diesel but not enough to compensate for the $$ difference..IMO! THANKS
  6. Gravely_Man

    Gravely_Man LawnSite Silver Member
    Messages: 2,075

    If and that is a big if I could afford it then I would go with a diesel hands down. They are great. Eric Elm was getting incredible amounts of time out of his diesel engines.


    WREBELMACHINE LawnSite Bronze Member
    Messages: 1,089

    I bought a diesel bladerunner last year and just bought a new bladerunner diesel to with it this year. For years I have been using gas engines but after the first diesel there is no comparision in fuel savings, power and the production between the two is incredible! Now I am not comparing the same brand of mowers but when you compare the engines there is a big diffrence! As far as longevity I personnally think if you find the right mower set up correctly you should be able to get 10,000+ hrs. out of the machine. Of course that is not considering employees!
  8. Ricky

    Ricky LawnSite Member
    Messages: 154

    I have the DC XWD-2600. I love mine. I burns about .8 gal of fuel and I almost always run dbls. I have several ac. that I cut about once a month without any problem (don't use dbls on these). Diesel is usually cheaper, but not at the moment. Not all the gas stations carry diesel so this is a little bit of a hassle. Diesels are heavier and will show it on wet ground but it gives you a smoother ride on rough property. Also consider that with it being water cooled, you will have more belts, hoses, and other things to keep an eye on. I have not replaced a belt or hose with over 700 hrs. yet, I know that that could happen any time.

    When I was researching mowers, I kept seeing Eric Ericsons name about his Choppers and dependabality. That is how I met him on the web. He led me to this forum when he was the moderator here. I remember him talking about the hrs. that he had on his DC's. These were gas at the time. He was also looking into getting a diesel and said that "diesel is always better". Well, I got it and he got one the next month or two. It didn't take long for him to surpass the hrs. that I had on mine. As far as I know, he still liked his when he passed. I miss chatting with him about those Choppers.:(:(:( He enjoyed talking about them.:)

    Good info sdwally!
  9. dr grass

    dr grass Banned
    Messages: 242

    diesel diesel diesel!!!! so you run the mower down before the motor pukes! so what!!! look at all the money you saved on fuel and repairs over the course of time you owned the thing!! daaaaa!!!!!

    shep :eek:
  10. cantoo

    cantoo LawnSite Silver Member
    Messages: 2,910

    If the diesel outlasts the mower then just get another mower take the gasser out sell it outright then drop the diesel in and back saving money.
    I buy reel mowers with diesels in them and just resell them for the motors. Last year I bought two Buntons with Kubota diesels in them for Can$1100 they had around 1200 hrs on them. Made some good money. By the way our daily mowers are gas. :)

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