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Thread: 1970 Jeep cj5 restoration

  1. #1
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    1970 Jeep cj5 restoration

    I have been working on my wife's 1970 cj5. I had the engine rebuilt and it seems to run good except there is a knock that I can,t fiqure out where its comming from. Any help would be appreciated.

  2. #2
    Super Moderator LarrBeard's Avatar
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    Okay - let's get a bit more information:

    Does it knock at idle?

    Does it knock under acceleration?

    Does it knock at speed just moving along?

    Does it knock under deceleration?

  3. #3
    Senior Member 56willys's Avatar
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    What motor is it? Another thing to add to Larry's questions. Does it knock when cold, hot, or all the time. If its a rod bearing then the knock should fade after warmup. If not its likely something else.

  4. #4
    Super Moderator bmorgil's Avatar
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    Does it have oil pressure?

    A wide open question you posed there Garry!

  5. #5
    Super Moderator gmwillys's Avatar
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    Welcome Garry Smith,

    The more information the better on when you are experiencing the knock. Another question to add is what is the speed of the knock? Is the knock at crank speed or faster than crank speed for a valve train?

  6. #6
    Super Moderator bmorgil's Avatar
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    Serious engine knocks (the kind that ruin crankshafts, rods and blocks) typically also have low oil pressure. A knock combined with low oil pressure is serious. A "tick" or knock occurring at twice engine speed as gm is asking, are probably coming from the valve train and doesn't usually affect the oil pressure. Knocking sounds that are not rhythmic with the engine might be coming from the exhaust or other sources.

  7. #7
    Super Moderator gmwillys's Avatar
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    Exhaust dampers can come lose and cause a knock, but as Bmorgil said, it is usually non rhythmic.

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