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Conventional or Synthetic oil for 4 cycle equip.?

Discussion in 'Mechanic and Repair' started by RPH2929, Apr 13, 2007.

  1. RPH2929

    RPH2929 LawnSite Member
    Messages: 8

    For your 12 hp + equipment, what do most people prefer, conventional or synthetic oil?
  2. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Messages: 4,289

    Synthetic for us.

    1.It runs cooler and heat is the main killer for these air cooled engines.
    2.It is more stable at higher engine temperatures so it doesnt gum up etc etc.
    3.It maintains its viscosity better.
    4.It is slicker than dino oil and causes less wear on the crank journals, rods and cylinder walls. These engines do not have rod bearings so the slicker the oil the better.
    5.It contains higher amounts of detergents which is important to these engines because of the environment they are run in.

    There is no up side to the use of conventional dino oil other than it being cheaper. Sometimes you really do get what you pay for.
  3. Jason Rose

    Jason Rose LawnSite Fanatic
    Messages: 5,858

    Conventional for the first 50 hours, at least, for proper break in of engine. Synthetic after that.
  4. Lynden-Jeff

    Lynden-Jeff LawnSite Bronze Member
    Messages: 1,405

    I find synthetic a waste. I change my oil twice as often as recommend and filter 4 times more often then recommend and I would never think about doing it with synthetic. I'm sure synthetic is better oil but more frequent changes seem to do the trick for us.

  5. Bustus

    Bustus LawnSite Member
    Messages: 181

    How about for smaller engines, like push mowers? Does anyone use synthetic in them?
  6. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Messages: 4,289

    Im sorry but I am not going to change the oil every week like some guys "claim" they do. If I did everything that a person is supposed to do I would never have any time for myself or my family. Would it blow your mind to know we change our oil 3 times a year and in over 20 years have never had an engine failure due to oil problems? Not only that but it costs us less money and less time to do it this way. :dancing:

    Mobil 1 + Purolator pure one = One happy engine!
  7. lzrj

    lzrj LawnSite Member
    Messages: 245

    Does Mobil 1 make a sraight 30 weight? Is there any harm in running say a 5w-30 or 5w-20 oil. I totally agree with synthetic oils being the way to go. These types of engines only require around 2 quarts, so that only a few dollars extra to protect a 7-12k machine.
  8. Jason Rose

    Jason Rose LawnSite Fanatic
    Messages: 5,858

    There is a large difference between 5w-30 and 30 weight oil! If your book calls for 30wt. for hot weather, then I'd just stick with that, and no, there's no 30wt in synthetic that Iv'e ran across. Most newer engines, Kohler and Briggs take 10w-30. Kawisaki I'm not sure about.

    I know a couple guys that use ONLY 15w40 in everything, gas or diesel. You can get it in a synthetic blend, and 100% synthetic now too. Iv'e heard that it does fine in everything, and has a lot better detergents and is a better grade of oil that most 30wt or 10w30. Best part is not having to have 3 or 4 different weights of oil in the shop.
  9. lzrj

    lzrj LawnSite Member
    Messages: 245

    Just pulled out the owners manual for the kawi FH721V (25 hp). It give the following weights for the temps. 68F and up = SAE 40..... 32F to 95F = SAE 30....-4F to 95F = SAE 10W-30 or 10w-40...... and -10F to 32F = 5W-2.
    It also states that using a multi grade oil will increase oil consumption and to check it more often. Dont understand why. If these engines are running in hot weather mostly, a straight 30 or 40 weight has no limits of how thin it gets. Thats why multi grade oils were created. A 5W-30 will have a flow of a 5 weight when cold and thicken to a 30w when hot. Sounds better to me than using a thicker oil for start up since thats where most of the wear starts. But small engines may be totally different than car engines.
  10. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    I think everybody does it a little different, I am learning there is definitely a trick to breaking engines in, nothing one can explain it just takes practice, but beyond that it is also a matter of sheer luck and factors beyond our control (as in, which of the thousands that rolled off the assembly line did YOU get?).

    The last Kohler I bought, I put conventional in during the break-in, and within minutes of starting it pushed it to the limit and held it there (by forcing the spring-loaded lever manually beyond the factory set full throttle point). One of the valves did crap out and I had to fix that, but then I ran it through some yards at some pretty high rpm's and once I got it to 8 hours I switched to synth and it is the best engine I own, I can rev it so high it literally turns the muffler red hot (but I turned it back down, it still runs a bit higher than standard WOT thou, niiice).

    It may sound stupid, but I am out to prove that with synth an engine can sustain right-at redline rpm's indefinitely.

    I run synth in everything, except for the break-in period (8 hours in my case).
    Yup, even the truck, I don't have a quart of conventional anywhere.
    As for the money, I change oil once / season in most of my machines, unless it turns darker than I'd like to see.

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