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help is it a knock!??!?!?!?!?

Discussion in '40- & 55-Series Tech' started by Mavric1298, Mar 31, 2003.

  1. Mavric1298

    Mavric1298

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    I just was driving home from school, and there is this horrible noise.  The hood of the car is slightly open, cause the PO put blocks under the hood hinges to aid in cooling before he put the new bigger rad. in.  It started to rain, and all of a sudden there was this horrible noise.  It sounds kinda like super loud exhaust, almost a putting noise.  COULD THIS BE AN ENGINE KNOCK?!?!?!  it speeds up with engine speed, but she'll start up after i turned her off (once).  I towed her to our school parking lot and thats where she sit now, what should i do?!  I was thinking maybe the exhaust man. cracked or something cause of cool water getting in?  She does have an air cleaner, and the opening was dry, so i dont think any water could have gotten in, the oil is at a exceptable level, and i just drove her 120 miles home yesterday, please help my new baby! by the way, 350, with a 400 cam=383 chevy
     
  2. CruisinGA

    CruisinGA

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    Does it still start up? What about coolant? When/if it starts what does it sound like?
     
  3. Mavric1298

    Mavric1298

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    She has started twice for a few seconds (cause i shut her down right away) and she has been at exactly 190 degrees, with 50psi oil pressure both starts, which is what she normally runs at, and when she does starts, its a super loud PUT PUT PUT type sound, but LOUD
     
  4. CruisinGA

    CruisinGA

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    Sounds like you maybe blew a exhaust gasket, or broke a bolt holding the manifold on. Open the hood, stand back, look at US DS of the engine while someone starts it. See if you can see any smoke coming out between the block and manifold.
     
  5. Mavric1298

    Mavric1298

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    Do this on both sides i take it. Luckly she blows a touch of black smoke on start up, but never other then that, so maybe i'll see some. I looked and all the bolts where on, so i'll give that a try tomorrow, im just worried if its deep engine that starting/running it will just mess things up even more/junk the engine
     
  6. woodchuck

    woodchuck

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    What are the chances you recently performed a tune-up? I once bought a beater used toyota pickup from a car lot. On the way home it spit a spark plug or it backed out what ever. It scared the living sh*t out of me.
     
  7. Mavric1298

    Mavric1298

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    Nope havent yet. Tomorrow im doing all fluid drain/and or flush, plugs, header gasket, collector gasket, oil pan/gasket (to check rods), and timing, sound like a good checklist?
     
  8. CruisinGA

    CruisinGA

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    Check for all sparkplugs like woodchuck said. I once tried to start mine with the dist. cap on backwards, and only 2 cylinders were firing. (wasn't me that put it on backwards) Made a LOT of noise, but hey it still ran(kinda rough tho). So yeah check the plugs too.
     
  9. Gumby

    Gumby Supamod Staff Member s-Moderator

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    It doesn't sound like a knock to me. A knock sounds a lot like a knock with your knuckles on wood. Maybe a spark plug, maybe a manifold leak.
     
  10. Gumby

    Gumby Supamod Staff Member s-Moderator

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    Mav,
    I just saw your latest post on pirate and my stupid browser on my kids computer won't let me log onto the PBB. You're header gasket blew right next to the plug that had the toasted insulator.
    No worries.
     
  11. Mavric1298

    Mavric1298

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    Sounds good to me, miss-firing cylinder, and ehaust leak=loud noise...