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Camshaft end play??

Discussion in 'The Garage' started by southernspeed, Jan 8, 2005.

  1. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    I've just put a new edelbrock TBI cam in with a new OEM style timing chain set.
    (Edelbrock say you have to use theirs but I can't see why)
    My book says camshaft end play should be zero but there is nothing to stop it 'walking' out. Infct if I pull on it I can pull it out by a good 3/16" so where are they measuring a zero end play?
    Or am I missing something very obvious here??
    Thanks:grin:
     
  2. bigblock44k5

    bigblock44k5 1/2 ton status

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    Think they mean end play as in side to side not in and out. Its normal for it to have in out movement the chain will keep it in place.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    They are talking about measuring it after the timing chain cover is installed I'm sure, my Crane roller cam wanted minimal end play.

    I believe there is a plug on the end of the block that if removed would allow you to measure end play, but otherwise, it was stick a screwdriver against the edge of a cam lobe and see how much it moves.

    Fairly worthless measurement, since the timing cover isn't stiff enough to keep the cam in place.
     
  4. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    OK thanks guys. I was thinking it was a bit of an odd one!:)
     
  5. HarryH3

    HarryH3 1 ton status Author

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    Flat tappet cams have a very slight angle ground into the lobes. Each lobe is ever so slightly larger at the rear edge than it is at the front edge. This serves 2 purposes. First, as the cam rotates, the pressure of the lifters on the lobes causes there to be a slight rearward force on the camshaft. This keeps the cam from walking in the block. Second, it causes each lifter to always rotate in its bore, so the friction between the lifter and cam isn't concentrated on a single part of the lifter.

    Roller cams don't have the angle ground into the lobes. This is why roller cams require a cam retainer or cam button to keep the cam from walking forward. :cool1:
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    So why does his (assumed) flat tappet cam recommend checking end play? I've installed but one flat tappet cam, and I don't ever recall endplay being something to check, maybe it was just selective reading on my part. :)

    Roller cam can't "walk" forward due to the cam button obviously, but you still need minimal end play so the rollers track along the same general path on the cam lobe.
     
  7. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Now that's what I call an informative answer! Thanks. It's all together now anyway but it's good to now for peace of mind anyway.:grin:
     
  8. HarryH3

    HarryH3 1 ton status Author

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    I'd guess that Edelbrock has an typo in their cam install sheet. ;) Prolly a cut-and-paste error between the instructions for the two different cam types. I don't recall any end-play check during cam swaps either.
     

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