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extra tight valve after fairly recent re-shim, what's going on?

Discussion in 'XJ Technical Chat' started by seca550RK, Apr 18, 2015.

  1. Polock

    Polock Well-Known Member

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    just put the shim in right this time
     
  2. seca550RK

    seca550RK Member

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    I went from 250 down to 230 (my smallest shim) and still only have ~.04mm clearance. I'll crank it over a few more times and see if it seats more.
    Anyone have some links to good rebuild threads?
     
  3. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    I'm not assuming anything. Be sure to turn the crank several rotations before checking the clearance with the 240 so the shim is fully seated.

    EDIT: If you still have a tight valve after the 230 is fully seated you will be visiting a machine shop or getting a used head. Valve seat replacement is not a DYI job.
     
  4. Polock

    Polock Well-Known Member

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    don't hear of valve seats getting beat that far into the head on these that fast. I'am thinking it's more likely a nick in the bucket not letting the shim seat properly. So if all else fails before you take the head off, take the cam out and pull that bucket out. Now you can give it a good eyeball and make sure it's seating right. You're going to take the cams out anyway.
     
  5. seca550RK

    seca550RK Member

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    So I cranked it over at least 6-8 times but still no improvement. When I took it for a test drive It did seem to have more valve chatter than I'm used to so I'm going to take another look and see if it has seated.
    There is definitely something weird going on. The nick in the bucket idea sounds interesting but I did have a proper clearance last time so it doesn't explain why it's still changing so fast.
    taking the cams off does sound like a reasonable first step. I have been using this as my daily driver so I might need to figure something out out while I fix it. This doesn't sound like a weekend project. Luckily I live within biking distance of work if all else fails. lol
     
  6. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Nevermind... Polock got it
     
  7. seca550RK

    seca550RK Member

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    I think Polock is onto something. I took it for a couple mile ride last night, and rechecked the clearance this morning. I've got .10mm clearance now, but I did
    notice that it will tighten up if I spin the bucket and recheck it. I'll see if I can pull the bucket next week and figure it out.
    Thanks for the help.
     
  8. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    If you're checking it after you run it, you will get inaccurate readings. It must be checked with the engine COLD. If its been even just fired up, the heat will cause expansion and change the gap.
     

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