Signs that point to rebuild

Engine & Related

  1. richardgoesfast

    richardgoesfast Active Member

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    I've got a 1970 383 that shows 34,000 and change on the odometer. Although who knows what that actually means.
    So I don't know the history of this car, and really wondering if engine was ever rebuilt. Are there any signs that indicate a rebuild? If the car says 34,000 maybe that means 134,000, and there is no blue smoke out the tail or anything like that.
    Engine bay does look pretty clean, I will say that.
    Any ideas appreciated.
     
    roadrunnerbob likes this.
  2. quikbird

    quikbird Well-Known Member

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    Compression test the engine and see if get a god reading. If low means the 134. How fast it leaks down can also tell you how well the rings seal to the cyl walls
     
  3. 69hemibeep

    69hemibeep Sponge Bob Square Wheels

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    Again I agree with quiky :poke:
     
  4. richardgoesfast

    richardgoesfast Active Member

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    I'll get a compression meter, and guessing if I do this on 2 - 3 cylinders that should give me a pretty good idea of whether this thing has been rebuilt.
    Is 134 psi the figure for a healthy engine. Again, I've got the 383.
     
  5. quikbird

    quikbird Well-Known Member

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    Probably should be closer to 150. What you also want is all the cylinders to come in within 10% of each other. The 134 is my reference to the mileage and I was being lazy on typing. My note on leakdown was it gives you an idea of the wear in the cylinder.
    There is a engine builder on the site who could probably offer some really good advice
     
  6. quikbird

    quikbird Well-Known Member

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    Bob are you well, not terminally ill?? Agreeing with me I’m just not used to.
    :lowdown::rofl:
     
  7. richardgoesfast

    richardgoesfast Active Member

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    Got it 150 psi. I'll put this on the list of things to do. Really would like to know if there has been a rebuild.
     
  8. 69hemibeep

    69hemibeep Sponge Bob Square Wheels

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    do all the holes and then go back and do them again with a couple squirts of oil in them to seal the rings. This will give you a look at the valves vs rings.
     
  9. richardgoesfast

    richardgoesfast Active Member

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    Got it. Will do it.
     
  10. quikbird

    quikbird Well-Known Member

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    All of these will just give you a hint. Almost have to start taking the engine apart to be sure. If you can pull the oil pan you will then be able to see the main bearing girdles. If they have stamping on them to help identify them such as numbers or letters someone has been inside the engine.
     
  11. Russ69Runner

    Russ69Runner Well-Known Member

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    I got a 383 and the motor will have a stamp on it some where if they bored it over. The put a small o and 30 after my vin number on the motor by the oil pain up front on the passenger side. It has new freeze plug's in the back. But I will pull the motor down and look at the crank main bearings. Also look at the cylinder wall check the cross hatching this can tell you a lot and look for scoring in the cylinder. Check cam bearing's and the cam. Hoping that all I have to do is reseal and gasket the motor and rebuild the water pump. Think I will install a new fuel pump push rod while in their. Good luck Hope you find the motor in good shape and don't have to spend a small fortune on it.
     
  12. richardgoesfast

    richardgoesfast Active Member

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    I'll look for this. I had no idea that a rebuilder would actually write in that it was taken 30 over. That's pretty cool. I rebuilt a Vette once, don't think my guy ever thought to do that.
     
  13. ACME A12

    ACME A12 Plaid Sport Coat Wearing Moderator Staff Member

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    Most machine shops don't, so don't count on this...
     

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