Kohler CV-22 crankshaft gear position

Discussion in 'Mechanic and Repair' started by KenM, May 3, 2011.

  1. KenM

    KenM LawnSite Member
    Posts: 18

    Having a problem with a Kohler CV-22 - see my earlier thread dated 4/29 on this forum - and am wondering if the gear on the crankshaft might have shifted when I threw a rod (it wasn't pretty). It appears that that gear is not keyed to the crank, but is probably just pressed on. If that gear has shifted a bit, it obviously will throw off the valve timing, maybe accounting for my loss of compression as the lifters pump up. So the question is: anybody know what the correct position is for that gear, relative to the keyway at the other end of the shaft (or any other reference)? Thanks!
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    I haven't seen nor heard of gear slippage issues, But I'm not saying it couldn't happen.

    This is the best I can do in relation to crank/valve timing;


    [​IMG]


    That will be the pto end keyway they're speaking of.....
     
  3. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    The crankgear is a zero fit ( The gear is heated and installed on the crank)
    The gear is in the right position when the timing dot is lined up with the line cast into the counter weight. The line will be about the width of a tooth on the gear and have a ground finish.

    They dont usually slip..they crack and break.
     
  4. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    This picture should help

    IMG_0139.JPG

    IMG_0141.JPG
     
  5. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Posts: 450

    I agree with Piston slapper on the dot. Pretty much lined up with the casting mark.

    I must dis-agree on the slippage issue. Have had 3 do it in the last couple of years, 2 verticles, and one horizontal. Exmark, Dixie chopper, and Bobcat. The chopper just happened 3 weeks ago. Crank was over $200.00
     
  6. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Posts: 450

    Not trying to make you spend money, but replace the cam if you replace the crank. Only reason I say this, just like a ring and pinion, they wear in together. Replace the crank without the cam, you'll be pulling it apart in a couple of weeks.

    Ask me how I know:eek:
     
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    OK....somrbody's gonna ask sooner or later....
    HOW DO YOU KNOW?:confused:
     
  8. KenM

    KenM LawnSite Member
    Posts: 18

    Thanks for all the replies! I pulled this engine from the mower a few hours ago to see where my crank gear dot is, relative to the casting midpoint. It's right where it should be. Maybe I should be happy since I'm not looking at a new crank and cam. But, something is interfering with compression during the starting process and all I can think of is that the lifters are pumping up and not relaxing fast enough, allowing one or more valves to not close on time. So, cam/valve timing is not the culprit. I'm gonna yank the heads apart and measure the new valve lengths vs the old valve lengths (not likely to be the problem, but may as well rule it out); also gonna evaluate the valve springs vs those from a sister engine. Do they weaken after 1700 hours? I'm getting close to just shimming the rockers up as piston slapper previously suggested, but I'd sure like to understand what's going on. Thanks again for all your help to this point. Any other ideas?
     
  9. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    I just read your other thread, Did you ream the valve guides to proper oil clearance for the .25 oversized valves ?

    You can't go by feel, They must have 0.056mm or 0.0022in clearance for proper oiling so they won't bind in the guide.

    The valves may have "felt" good until you added the tension of the spring, Then add the rocker arm not pushing the valve open dead center and square could cause valve/guide binding.....

    What I'm getting at is the engine ran until it blew, The only thing that changed was the oversized valves so that's where I'd be looking.
     
    Last edited: May 4, 2011
  10. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    DITTO....DITTO....DITTO...etc.....

    KenM ...you created your own problem....It aint the valve springs.

    Sharpcut1....still waiting for you to learn me up about cranks and cams....

    RestroRob...Are we speaking a foreign language ? This aint rocket science...
     

Share This Page