Valve chatter at high rpm’s

Discussion in '40- & 55-Series Tech' started by Ian Rogers, Nov 7, 2005.

  1. Ian Rogers

    Ian Rogers

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    So on the way back from surf n turf I was experiencing valve chatter when on the freeway in 4th gear. It would only happen when I would load up the truck i.e. going 55mph and give it more gas. It only seams to happen under load. What could be causing this? I ran a quick go-no go valve clearance check and they were all right on. Intake .010” and Ext .014”. I am running a E-67 135 F motor with the timing bumped to about 10* with a NON-USA distributor

    Thanks for the help

    Ian
     
  2. trekker

    trekker

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    Just last night I noticed a chatter and thought it was valves at high rpm but discovered that my clutch slave needed a little adjusting. Sound went away with a little pressure.

    Just trying to eliminate the obvious (or stupid stuff) first. :)
     
  3. honk

    honk

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    Sounds like spark knock, preignition, whatever. Low octane gas and/or too much advance under load is the usual culprit.

    If you were to keep your foot in it while it's doing that you could find yourself with a hole in a piston, but most of the time if you just back off when you hear it you'll be OK. I wouldn't use the sound as a tachometer - waiting for it before downshifting or letting of the gas. That's a dangerous practice.
     
  4. IDave

    IDave

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    Yep. Ping.
     
  5. Pin_Head

    Pin_Head

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    X3

    Sorry I missed it. Sucks having to work.
     
  6. Ian Rogers

    Ian Rogers

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    you guys got it i turned the timing back 1/2 turn and it ran like a champ
     
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