Kohler needs rings

Discussion in 'Mechanic and Repair' started by Ciero, Jun 4, 2009.

  1. Ciero

    Ciero LawnSite Member
    Posts: 18

    I have a cub cadet with a Kohler 18hp magnum. It smokes really bad. I pulled one of the heads and can see a pool of oil in the cylinder. The piston has some slop in it. Is there anyway possible that I can just swap the rings without getting a new piston, new bearings, boring the cylinder, etc. I am laid off right now and I need to get this tractor running again with as little cost as possible. I know that this isn't the right attitude to take when it comes to these things but the difference in spending an extra couple hundred dollars could mean I can't do anything with it. I don't care if it will need a rebuild in a couple of years or I don't get maximum performance out of it. I only run about 45 min a week. Thank you in advance.
     
  2. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 12,963

    I'll bump this along I have two 15hp Kohler engines that are burning oil and wondered the same. I am guessing that that may not be the only way oil gets into the top of the cyclinder. Maybe the valve steam seals leak also?
     
  3. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Ciero,

    Just to slap a new set of standard or .003" oversize rings in there is going to put you in the $150 range with the needed gaskets, Then the cylinders would need to be de-glazed/re-cross hatched so the new rings could break in. Now you are closer to the $200 range. The only way to tell if new standard rings would be worth the money/effort would be to measure the piston and cylinder bore. This would require a micrometer and telescopic gage with proper measuring procedures/specs.....
     
  4. Ciero

    Ciero LawnSite Member
    Posts: 18

    Thank for the reply. This will probably be the route I will take. I will let you know if I wasted my time by not doing everything that I should have done. There are some gouges in the cylinder and should probably need to be bored. But I am not interested in swapping the pistons so I will see how it goes.
     
  5. VegetiveSteam

    VegetiveSteam LawnSite Senior Member
    Posts: 297

    In answer to your question yes, you can just buy and install new rings without doing all of the other things your mentioned. Now the next question is, will that help your problem? Maybe, maybe not. Like Rob said you need to have the bore measured. If by some miracle you have only ring wear and no major bore wear you may be able to just go back with a standard set of rings. And again back to what Rob said you would need to have the cylinders deglazed. If the bore is worn to the point a standard set of rings won't help then all you can do is bore it to the next size over which would be
    .010 or .020 depending on the wear. A .003 over sized ring set could be a great help if they existed. Kohler does offer a .003 piston and ring set but it's only the piston that is .003 over size. It's a common misconception that the rings are also over sized but they just standard rings. New rings might help reduce your smoking problem but there are no promises.
     
  6. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 12,963

    I'll try my question again maybe dumb but can't oil get past the valve stem bearings?
     
  7. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Sorry Ed,

    Valve stem seals do help to reduce oil intake into the cylinder during operation, But... When a seal does go bad it only lets a small amount of oil past the valve guide which in most cases is not enough to cause continuous heavy smoking/pooling of oil.

    If the seal/guide was worn enough to let oil past to pool in the cylinder then the valve would most likely not seat well enough to let the engine run.
     
  8. Ciero

    Ciero LawnSite Member
    Posts: 18

    I should add that I check compression before taking the motor apart. I didn't do a leak down check though. The compression was at 90 psi. From my understanding this is probably normal for a motor with 900 hrs on it. I am hoping that I have a bad oil ring.
     
  9. RonAyersMotorsports

    RonAyersMotorsports LawnSite Senior Member
    Posts: 854

    This is not normal!!! More than likely your engine has had dirt ingestion from blowing filters out instead of replacing. I can't stress enough don't blow filters out!!!!!!!!!!!!!!!!!!!!!!!!!!
     
  10. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 12,963

    On something like a 15hp single cyclinder Kohler what amount of time could I expect on an air filter? Are you saying it would be better to just let the dirt build up on the filter rather than blow it out? I assume you are saying that blowing out a filter actually damages it? Would it be better to simply knock it against concrete to clean it up a little?
     

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