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any way to stop a motor from knocking?

Discussion in 'The Garage' started by thezentree, Aug 15, 2004.

  1. thezentree

    thezentree 3/4 ton status

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    my 97 vortec 350 knocks, and i'd like it to stop. is there anything short of a rebuild that would help this out?

    and almost as importantly, what exactly makes a motor knock? pinging is predetonation (correct me if im wrong), so what is knock?
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    knock=rod knocking on the crank=needs new bearing.

    you can just pull it apart and put new bearings and rings in it. northern sells a rering kit for this.
     
  3. bigburban383

    bigburban383 1/2 ton status

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    Higher octane fuel or boosters will prevent ignition knocking. A rebuild will stop the rotating assemble knocking.
     
  4. thezentree

    thezentree 3/4 ton status

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    i switched to a higher octane fuel to stop pinging, since the local stealership doesnt know their ass from a hole in the ground and screwed something up. but i digress....

    i'll take one new motor, please!
     
  5. TSGB

    TSGB 1 ton status

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    No hijacking here, but I would also like to know what leads to the conditions that cause an engine to knock. Just lack of oil changes...? My 3.8 in my Cougar knocks more than a Jehovas Witness...


    Damn furds.
     
  6. ntaj*ep

    ntaj*ep 1/2 ton status

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    There are many different kinds of knocks.
    I have heard fuel pump pushrods knock in a SBC. The "new" generation Vortecs have piston slap that in some trucks are louder than diesels /forums/images/graemlins/eek.gif(a condition deemed normal by the general /forums/images/graemlins/shame.gif) Also a cracked flex plate can sound like a knock. To properly pin point a sound like a konck you would need to find the area/conditions when it will appear.
    Usually a low pitched hollow sounding knock rythmic with engine RPM would indicate a rod possibly main bearing failure. But there are so many things that it can be its hard to say what caused it and how to fix it...
     
  7. thezentree

    thezentree 3/4 ton status

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    [ QUOTE ]
    No hijacking here, but I would also like to know what leads to the conditions that cause an engine to knock. Just lack of oil changes...? My 3.8 in my Cougar knocks more than a Jehovas Witness...


    Damn furds.

    [/ QUOTE ]

    in my case, its probably water intrusion from the time i almost hydrolocked it /forums/images/graemlins/doah.gif
     
  8. Blue85

    Blue85 Troll Premium Member

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    [ QUOTE ]
    any way to stop a motor from knocking?

    [/ QUOTE ]

    Turn it off? /forums/images/graemlins/dunno.gif





    Sorry.
     
  9. TSGB

    TSGB 1 ton status

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    So is there a way to hunt a knock down in an engine, and actually find out where it is without completely stripping it?
    /forums/images/graemlins/confused.gif
     
  10. diesel4me

    diesel4me 1 ton status Premium Member

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    You can use a mechanics stethoscope(looks like the doctors!)to help pinpoint the source of the noise,and by pulling the plug wires off one cylinder at a time it will usually deaden or reduce a rod or main bearing knock in that cylinder,wrist pin or piston noises usually get louder when the plug wires on that cylinder are pulled--be carful because the HEI ignition coil can put out up to 50,000 volts,use insulated pliers make for that purpose,or you'll get zapped for sure.Is your motor rapping(like a rod knock?)or is it just "pinging" like when you have cheap gas and overadvanced timing?. /forums/images/graemlins/crazy.gif
     
  11. thezentree

    thezentree 3/4 ton status

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    well, it does both, but it doesnt ping hardly at all anymore because i run 89 octane fuel. im thinking that i got water in a rod bearing and warped it or something
     
  12. down4thakrown

    down4thakrown 1/2 ton status Premium Member GMOTM Winner

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    try any lucas??
     
  13. thezentree

    thezentree 3/4 ton status

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    yea, it helped, and oil pressure is up about 10psi when at operating temps and idling, but its still knocking a little bit
     

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