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Pitted valve stems

Discussion in 'XJ Technical Chat' started by a100man, Mar 5, 2016.

  1. a100man

    a100man Well-Known Member

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    I just stripped a head as part of a new engine build project I'm going to try (gotta do something while my wife stares at soap reality tv nonsense). It's been exposed to water or moisture in the past (PO) as all the shims were pitted but now I also find the top 20mm of about half the valves are also pitted some only slight, the sealing rim at the valve heads probably just need a fine grind in with paste however. Since I think the pitted region is outside of the valve seal travel area could I get away with re-use ? At about 50 quid (70 USD) a po,p buying new would write off the bike ! I have another head but I fear that would be similar and it has worse cam journals that this one..

    Cheers

    J
     
    a100man, Mar 5, 2016
    #1
  2. specialk

    specialk Active Member

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    As long as the pitted region doesn't come in contact with the valve seal then it shouldn't be a problem. If not, the only problem you'll experience would be small oil consumption. You could try put a bit of jb weld on the pitted areas then wet sanding the valve stems to remove the excess. Rather crude method but I know some people do it with pitted forks.
     
    specialk, Mar 5, 2016
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  3. k-moe

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

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    It'd be easier to evaluate with photos of the affected area of each valve. Missing material can lead to cracking and dropped valves.

    A for filling in the pits with epoxy; don't. Valves run in a far harsher environment than fork tubes do.
     
    k-moe, Mar 5, 2016
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  4. hogfiddles

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

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    I wouldn't do that with engine valves....
     
    hogfiddles, Mar 5, 2016
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    k-moe likes this.
  5. k-moe

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

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    Why? Don't you like rebuilding engines?
     
    k-moe, Mar 5, 2016
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  6. hogfiddles

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

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    I meant I wouldn't do the " fill the pits with epoxie/JBWeld/etc" procedure for valve stems....
     
    hogfiddles, Mar 5, 2016
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  7. hogfiddles

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

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    Uh..... You said that as a joke, didnt you? I just got it......lol
     
    hogfiddles, Mar 5, 2016
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    k-moe likes this.
  8. k-moe

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

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    I did. I am subtly hilarious. There are jokes I told decades ago that people are just now laughing at.
     
    k-moe, Mar 5, 2016
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    rocs82650, Stumplifter and XJ550H like this.
  9. cds1984

    cds1984 Well-Known Member

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    Would love to see pictures also.
    I have pulled a bunch of valves and never really paid much attention to the extraseal areas (so to speak) it would be interesting to do some analysis on valve grinding and replacement at some point.
    Oh and... K-moe... you are a funny bastard!
     
    cds1984, Mar 6, 2016
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  10. a100man

    a100man Well-Known Member

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    I'm hopeless with pics - maybe this works..
    [​IMG]
     
    Last edited: Mar 7, 2016
    a100man, Mar 7, 2016
    #10
  11. k-moe

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

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    Those should be fine to run IMO. There is only light surface pitting from the looks of it.
     
    k-moe, Mar 7, 2016
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  12. a100man

    a100man Well-Known Member

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    Hi K

    Meanwhile I have harvested some other valves from my extra spare head that look better (apart form teh one that's
    shaped like a cork-screw - from the cylinder that threw its rod...:eek:

    I'll line them all up and pick the best I think.
     
    a100man, Mar 8, 2016
    #12

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