non honable kohler cylinders

Discussion in 'Mechanic and Repair' started by East Coast Lawn Choppers, Oct 10, 2009.

  1. East Coast Lawn Choppers

    East Coast Lawn Choppers LawnSite Member
    Posts: 134

    Has any of the rebuilders in here ever run into cylinders that can't be glaze busted or honed ??? We have three of them now... a 25, a 26 and a 27 they will not hone. It is almost like they are nickosil cylinders, but they take the same rings as all the others. The latest one is a 25hp CH25 spec 68606 and we ran the hone in it and it won't touch it at all. We bored one of them so we could use it. We still have 2 more here yet that I didn't want to bore. We even took one to the machine shop and asked him to try it , he put pressure on the stones and even went to his rough stones... barely left a mark in the bore. Only thought other than a crome bore is a lot of hours on it possibly overheating and causing it by heat treating the bore ???
    Any thoughts or knowledge ?
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    Bingo,

    Right from the manual, And it applies to both CV and CH engines. When I run across one I shortblock as stated.....


    [​IMG]
     
  3. East Coast Lawn Choppers

    East Coast Lawn Choppers LawnSite Member
    Posts: 134

    So I guess that is what it is... and they don't sell... or atleast my dealer the special rings for that bore. Even the kohler site lists the same rings for that spec as for the std ones. We have a machine that shop said they can bore them. We bore some but most we send out. Well if I have to do the shortblock at least I already refaced the valves and ground the seats and the heads are ready. It would have been back together today but... damn nickosil
    Where is the best place to get shortblocks at a good value ?
    or do you know whats the part number is for the proper rings because the cylinders look like brand new.
    Thanks
     
  4. Breezmeister

    Breezmeister LawnSite Bronze Member
    Male, from South Jersey
    Posts: 1,458

    Interesting, and this does not apply to the CH 27 ?

    And if I gave you the spec number off a CH 25, could you tell me if that is one of the chosen engines ?
     
  5. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    No, From my knowledge only the 25's and 26's......


    To find if your engine has the nickel bore, All you have to do is look up a piston or ring set. Kohler does not offer over-sized pistons/rings for the nickel bores only standard replacements for if the bore is still with-in usable specs, They only list over sizes for the bore-able cast iron cylinders.
     
  6. Breezmeister

    Breezmeister LawnSite Bronze Member
    Male, from South Jersey
    Posts: 1,458

    Thanks Restro, that explains alot :drinkup:
     
  7. East Coast Lawn Choppers

    East Coast Lawn Choppers LawnSite Member
    Posts: 134

    It is weird thou. All the dealers in our area and the Kohlerplus website say that they take the same rings as the std bore. From the spec # on ours it comes up with the 24-108-04-s rings (now 24-108-14-S) and they list over sizes and all. Did they start using just plain iron rings in all of them now ?
    Do you have a part number for the 25-26 hp rings for the nickosil bore ?
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    My Kohler dealer's website only shows standard rings for your CH25, The same number you posted. If the cylinder was bore-able they would have listed over-sized rings under the standard rings part number.....
     
    Last edited: Oct 15, 2009
  9. East Coast Lawn Choppers

    East Coast Lawn Choppers LawnSite Member
    Posts: 134

    So it does look like they almost all take the same number. The CH25 with the nikosil only lists std, but if you go to CH745-0007 it takes the same number std rings and then lists oversized too. I thought I remember a some of them having a chrome face top ring but now all the ones we get are all plain iron rings.
    Thanks for the help resto
     
  10. VegetiveSteam

    VegetiveSteam LawnSite Senior Member
    Posts: 297

    All CH,CV 25 engines and some CH,CV26 had the nickel silicone plating on the cylinders. Don't confuse that with the 25hp CH,CV730 which were cast iron bore. An easy way to know the difference is put a magnet to the bore. If the magnet attracts itself to the bore then it is a cast iron bore not nickel silicone. Also I know I'll get arguments on this but all Kohler rings are chrome. I know they are black and not shiny like you might think chrome would be but they are chrome.
     

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