Vertical engines vs horizontal engines

Discussion in 'Lawn Mowing' started by tacoma200, Jun 16, 2009.

  1. tacoma200

    tacoma200 LawnSite Fanatic
    Messages: 5,426

    I have heard that vertical engine don't last as long because gravity pulling down on the pistons wears the cylinder and piston out faster. No, I'm not sure I believe this. Vertical is the better design for most ZTR's and I see the trend going in that direction. Does any one have hard evidence that one type is better than the other? Or is there no difference at all? Of course with a Horizontal engines you get into all kinds of problems like the mule drive.
  2. kaferhaus

    kaferhaus LawnSite Bronze Member
    Messages: 1,444

    All I know is that after tearing down dozens of single and multi cylinder vertical shaft engines I've never detected any additional wear on the "down side" of the cylinder walls or pistons.

    That being said, the cyl and pistions will always wear more nearer the exhaust valve side of the cyl. However even that you don't see much if you're anal about changing the oil regularly.

    Our engines last a long time.... but we're anal about maintenance. I used to "re-build" them but the parts have gotten so expensive that it's actually cheaper to just buy a new one and strip the old of of good parts.

    Most of these engines do not have cam bearings (some automotive engines don't either any more... ) and that seems to be what finally "toasts" them.

    And while many guys do change their oil frequently they do not keep the valves adjusted... either out of ignorance or laziness... my dealer says most engines that he sees destroyed are from burnt/dropped valves and oil starvation (oil pump failures)

    In the "old days" LOL, when I was poor, I bought many a used clapped out mower for next to nothing, did a valve job and replaced the rings on it and used it for years afterwards.... but back then parts were comparatively inexpensive and my time was worth nothing.... spent many nights up until midnight or so rebuilding "junk" into something I could make money with. But... back then you could buy a "overhaul" kit for a single cyl Briggs for under $60 including new valves. The old cast iron Kohlers (good engines those were) were only a little more.
  3. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Messages: 2,524

    I've never heard that, either.

    Some manuafacturers (Hustler, etc.) only use vertical shaft engines to eliminate the mule drive. I had a 27hp LC Kawasaki SuperZ years ago with the horizontal shaft. That's when they used a gearbox which was pretty much a disaster.

    Come to think of it, that's the only ztr I've ever owned with a horizintal shaft engine. I guess I never thought about it until now, but I've never had any major problems with any of my vertical shaft engines.
  4. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    Old wive's tale.
  5. LEM

    LEM LawnSite Member
    Messages: 16

    Horizontal shaft engines can be more expensive if they have output shafts front and rear. Some mower designers would run the hydro pumps off one side, and the blades of the other. I believe that Grasshopper, for one, does this.

    Some mower designers claim that the horizontal shaft engines have better lube systems. I've never heard a good explanation for why they believe that.

  6. dakota2112

    dakota2112 LawnSite Member
    Messages: 55

    Theoretically speaking, isn't a vertical shaft engine more prone to leaking? The main crank seal in a horizontal engine only has to work when the engine is running. But in a vertical engine, the main crank seal is fighting an oil leak nonstop for 365 days a year, isn't it?

    (I have no real-world evidence to show this being a problem though)
  7. SfTD_service_CENTER

    SfTD_service_CENTER LawnSite Senior Member
    Messages: 868

    headgaskets are weaker on a vertical shaft engine. i have done tons of headgaskets on opposing car engines and it seems that like the vertical shaft motor on mowers that the heads are what have the issue. those being flipped have alot of movement that i can see would be a issue, that being said subaru is a over head cam engine and the mowers are pushrod so lol. but with heat disapation and the way they sit i can se a horizontal shaft motor running more efficient with heat disapation, because the way it sits the heads are high in the air and seem like than can catch some extra air, but if you carefully examine the specs at kaw power and kohler web sites i think the engine power advatage goes to vertical shaft motors, i havent loked in a while but i suggest anyone who is curious do so. im just saying what the specs say too so i have no brake dyno to test any of this.

    a neat engine design for a mower would be a v4! they ran them in hondas vfr 750 and 800 still do i think. and won championships with the rc45 race bike which was that design, maybe a horitantal shaft mower with the v4 would be a great new concept for power on a ztr platform i dont hear of any 4 cylinders other than the badboy.
  8. kaferhaus

    kaferhaus LawnSite Bronze Member
    Messages: 1,444

    I'd like to see one that did nothing but drive hyd pumps for the drives and deck. Hyd spindles would be awesome.
  9. TomberLawn

    TomberLawn LawnSite Bronze Member
    Messages: 1,299

    Like a WAM. They are all hydraulic.
  10. chesterlawn

    chesterlawn LawnSite Senior Member
    Messages: 704

    Do they make water cooled vertical engines for mowers?

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