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Valve clearance

Discussion in '1982-Present GM Diesel' started by Muddytazz, Jan 29, 2005.

  1. Muddytazz

    Muddytazz 1 ton status

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    My dad is finally putting his diesel tractor motor back together after it sitting for close to 4 years. What he needs help with is how to set the valve clearance on the rockers when the motor is cold?
     
  2. BlueBlazer

    BlueBlazer 1/2 ton status

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    You need to refer to a service manual for whatever model tractor it is.
     
  3. Muddytazz

    Muddytazz 1 ton status

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    Its not a matter of the clearance size as we know what that is, its just a matter of how to do it. Is it just like clearancing the valves on a gas motor? Cause all the service manual says to do is install the rocker arm assembly, set valve clearance and bleed fuel system. Doesn't explain how, or if you need the #1 piston at TDC or what?
     
  4. BlueBlazer

    BlueBlazer 1/2 ton status

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    Is this an I6 or V8?
     
  5. Muddytazz

    Muddytazz 1 ton status

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  6. BlueBlazer

    BlueBlazer 1/2 ton status

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    With #1 at TDC, you can set exhaust and intake on #1, and then either exhaust or intake on #2, then the opposite on #3, and # 4 should be on overlap so no setting there. Then, put #4 at TDC (compression stroke) and set all remaining valves. You can get all valves set with two revolutions of the engine. You may want to still refer to a manual since it has been a long time since I worked on a 4 cylinder, but the process above should work on all inline engines.
     
  7. Muddytazz

    Muddytazz 1 ton status

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    My next question, is how do you know when #1 is at TDC? I've never worked on a diesel so I don't know crap about them. I know with a gasser, you pull the spark plug. How do you know with a diesel and how do you know your on the compression stroke also?
     
  8. BlueBlazer

    BlueBlazer 1/2 ton status

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    There should be a way to externally tell if its at TDC. Some use a hole in the flywheel housing and a hole in the flywheel and a pin to line the two up. Some use a pointer and mark on the damper and there are other methods as well. Once you determine how to find TDC, finding whether you are on compression or exhaust is a matter of looking at the rocker positions. If both have lash, you are on compression (where you want to set lash). If they are on overlap (no lash) you are on exhaust.
     
  9. Diesel Dan

    Diesel Dan 1/2 ton status

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    I just hand roll the motor over and watch the valves. Watch the one that's open, wait till it closes and the other just starts moving. Not really technical:blush: but works when your in a hurry and don't have the firing order.
     
  10. BlueBlazer

    BlueBlazer 1/2 ton status

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    That would find what for you? TDC after the exhaust stroke?
     
  11. Diesel Dan

    Diesel Dan 1/2 ton status

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    I'm not so much concerned about TDC. Just making sure the lifter is on the base circle of the cam profile, regardless of TDC. It does require rolling the motor over more than once, so it could be seen as more time consuming:what: .
     
  12. Muddytazz

    Muddytazz 1 ton status

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    We have the firing order.....1, 3, 2, 4 so thats not a problem. Turning the motor over on the other hand is a problem. The motor is still mounted in the tractor, there is about 1/2" space between the crank pulley and the front axle pivot mount. Any idears?
     
  13. BlueBlazer

    BlueBlazer 1/2 ton status

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    Is there a hole in the flywheel housing to put in a turning tool?
     

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