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Shim check please

Discussion in 'XJ Technical Chat' started by Onetrackstu, Sep 16, 2014.

  1. Onetrackstu

    Onetrackstu Member

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    I just need a verification and suggestion on the ones with a question mark.

    Thanks,
    Stu

    1:
    Intake: .10mm
    Shim: 275
    Needs: 270

    Exhaust: .13mm
    Shim: 275
    Needs: 270

    2:
    Intake: .10mm
    Shim: 270
    Needs: 270 or 275?

    Exhaust: .19mm
    Shim: 275
    Needs: 270 or 275?

    3:
    Intake: .13mm
    Shim: 265
    Needs: 265?

    Exhaust: .23-.25mm
    Shim: 275
    Needs: 275

    4:
    Intake: .25-.28mm
    Shim: 265
    Needs: 280

    Exhaust: .13-.15mm
    Shim: 275
    Needs: 270
     
  2. quebecois59

    quebecois59 Well-Known Member

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    Why not using metric gauges for accurate readings?

    There is no way to tell what shim you need with a reading like .254-.279? It should be .25 or .26 or .27
     
  3. Onetrackstu

    Onetrackstu Member

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    I used a blade gap tool from advanced auto and it had SAE as well as metric to the thousandth. I rounded them to make it easier. I really with the US was all metric, so much easier.
     
  4. quebecois59

    quebecois59 Well-Known Member

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    intakes #1 and #2 have the same readings so shim should be one size smaller for both, so #2 shim to install should be 265.

    #2 exhaust is in spec so the 275 shim is correct. Same for #3 intake, it is in spec.

    #3 exhaust is one size too loose, you need a 280. #4 exhaust is two sizes too loose, you need a 275.

    You're correct with exhaust #1 and #4.

    I'd do the measurements one more time to confirm these readings.
     
  5. Onetrackstu

    Onetrackstu Member

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    Ok I'm a little confused but these are the ones I can up with as per your suggestions.

    These are the ones needed to be in "spec"
    1
    Intake: 265
    Exhaust: 270

    2
    Intake: 265
    Exhaust: 275

    3
    Intake: 265
    Exhaust: 280

    4
    Intake: 280?
    Exhaust: 275?
     
  6. BruceB

    BruceB Active Member

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  7. quebecois59

    quebecois59 Well-Known Member

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    Sorry I made a mistake with #4 in my last post

    Intake specs = between 0.11 and 0.15 mm

    Exhaust specs= between 0.16 and 0.20 mm

    Shim thickness increment is 0.05, so if you do the maths you should end with these shims:

    #1
    intake: 270
    exhaust: 270

    #2
    intake: 265
    exhaust: 275

    #3
    intake: 265
    exhaust: 280

    #4
    intake: 280
    exhaust: 270
     
  8. Onetrackstu

    Onetrackstu Member

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    thanks. for the help. here is what the fancy calculator came up with.
    [​IMG]
     
  9. quebecois59

    quebecois59 Well-Known Member

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    Oups, you put your exhaust readings in the intake calculator and vice-versa...
     
  10. quebecois59

    quebecois59 Well-Known Member

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  11. Onetrackstu

    Onetrackstu Member

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    Windows and Mac OSX directions here. It's an excel table you change values in.
     
  12. a100man

    a100man Well-Known Member

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    Not sure I get this, A measuring tool is a measuring tool irrespective of units. Once you have converted the clearance spec into thou' you're up and running (intake 4.4 -6.0) then you only have to remember that each shim is an increment of 2 thou - which is a bit lousy given that it spoans the whole of the intake spec :cry: .

    Also a lot of metric feelers only have a resolution of 0.05 (2 thou) which is pretty useless for this job.

    I understand that it's another variable to deal with but...

    To the OP - some of these clearances seem very wide - can you be sure you haven't got excessive carbon build up or other debris on teh valve. Once I had the head off mine and cleaned it up the clearances came down quite a lot.
     
  13. quebecois59

    quebecois59 Well-Known Member

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    There is no guessing with the proper set of metric guages, you get the readings at a .01 mm resolution.
     
  14. quebecois59

    quebecois59 Well-Known Member

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    What are the results of the calculator with the readings at the right place?
     
  15. hogfiddles

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

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    I just use metric feelers, and I have a printout of the factory shim chart that I have laminated, so I can look at it at a glance.

    No need for converting sae to metric, or doing a fancy excell spreadsheet or anything.....

    dave
     
  16. BruceB

    BruceB Active Member

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    so....did you get your valves in spec?
     

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