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Thread: Sticking Valves

  1. #1
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    Sticking Valves

    My 3.9 Disco 1 has just been diagnosed with having sticking valves leading to a rythmic misfire at idle and low speed/high load conditons. Apparently quite a common problem with these. Ran Vaktek concentrate through inlet to clean valve stems but it's still not right.

    Apart from removing the heads, do any of the bottled injection/carbon cleaners work - Redex, Nulon etc. Seem to recall there was a process called carbon clean around not long ago too.

    Anyone else had this problem?

  2. #2
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    ... NO

    ... YES

    Our experience with sticking valves, especially with late 3.9/4.0 is ....

    Off with their heads! Have the guides reamed, back together, and hiho, Silver, away!!

    HTH

    Pete
    Last edited by Pierre; 2nd December 2008 at 06:40 PM. Reason: /S
    Dizzie, 08 D3 TDV6 SE

  3. #3
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    some of those things will provide a temporary relief....

    but for the long run, heads off and rebuild with kliners.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

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  4. #4
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    I had the same problem with my 3.9 Rangie. Compression was ok but vacuum very low, erratic dying on idle, but ok on revs. 200000km on motor half on LPG. Heads off and found heavy black coke up on the back of inlet valves especially and several varnished sticky valves. Being on LPG also dries out the guides. Pistons quite clean and minimal bore wear.

    Probably got too deeply into it but got concerned about wear on the valve train behind the sticky valves - especially cam lobes and lifters and consequent lack of valve lift/gas flow. Have ended up pulling out camshaft, timing gears etc to do the lot and not go there again for hopefully another 100000.

  5. #5
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    Quote Originally Posted by Blknight.aus View Post
    some of those things will provide a temporary relief....

    but for the long run, heads off and rebuild with kliners.
    What he said!

  6. #6
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    What are kliners? Are they top quality valve guides or inserts? Where can you get them?

  7. #7
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    Quote Originally Posted by aRRon View Post
    What are kliners? Are they top quality valve guides or inserts? Where can you get them?
    K-Lines are a phosphor bronze insert that is machined into the original guide.

    Main benefit is that the tolerances can be far tighter than std cast iron guides and the chances of seizing or sticking even with these tight clearances is minimal if at all and they are about 5 times stronger than cast iron.
    Problem with removing the whole guide is that you disturb the guide to bore contact surface and in an ally head that can mean problems with sealing and needing to oversize the guide to compensate.
    Its easier, cheaper and far more reliable than replacing the whole guide.
    Most head specialists that do major port work will K-Line valve guides allowing them to run shorter guides with tighter clearances due to machining the bottoms of the guides in the ports, plus in Rover V8's run shorter guides at the top to allow for bigger valve lifts.
    The valve retainers in late V8's have a clearance issue with the top of the guide when running high lift cams.

    But i could go on.......

  8. #8
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    Thank you very much LovemyRangie - that is exactly the solution I needed for my guides.

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