Knock knock!

Discussion in 'Race 400/430/455' started by alan, Mar 2, 2002.

  1. alan

    alan High-tech Dinosaur

    Who's there? :rolleyes:

    What will make an engine knock besides main and rod bearings? The mains look OK so far (cap side) except for a little discoloration. I will look at the rods tommorrow, but I didn't see anything unusual when I turned the engine over or wiggled the rods on the crank. If I stacked a rod bearing I think I'd get more than a muffled knock, more like Bang-Bang! (been there!) The flex plate is a thick SFI approved unit. The valve train looks OK. Didn't see pieces of piston missing! :Do No:

    Any ideas for other places to look?



    I had a muffled KNock and found it to be a loose torque converter bolts and I double checked the flywheel bolts too :Do No:
  3. alan

    alan High-tech Dinosaur

    I did find the center of a converter stuck in the end of the crank where the pilot bushing goes! I'll double check the bolts holding the flexplate on.

    If I don't find anything, I'll put it back together and run the poop out of it! :bglasses:
  4. alan

    alan High-tech Dinosaur

    Well, I found nothing nasty with the rod bearings. Other than piston slap or a loose wrist pin, (and converter bolts) I don't know where else to look.

    I hope I don't find out the hard way! :ball:

    GSXMEN Got Jesus?

    Have you tried isolating the area of the noise with a stethoscope?

    Wouldn't the cam bearings/cam make a noticeable noise if one or more went bad?

    Maybe the fuel pump rod/timing chain area?

    Let us know what you find.

  6. QuikBuik

    QuikBuik Yeah, it's Buick powered

    Scott just hit my next question. Fuel pump arm??
  7. alan

    alan High-tech Dinosaur

    Nope, I'm using an electric pump. Here's a picture of the cap side of the rod bearings.

    Attached Files:


    GSXMEN Got Jesus?

    How's the crank look? The bearings don't look bad - although the top one looks like it's wearing a little different.

  9. redbuick

    redbuick Well-Known Member


    alan, make sure none of the rods/rod bolts are hitting the oil pan in the front half, there isn't much room here and if the pan is bent in just a little it can make contact here....seen it happen......
  10. alan

    alan High-tech Dinosaur

    The main bearings look about the same as the rods. The top rod bearing looks "stained", but feels smooth. The engine has a main girdle, so the pan is about 1" lower than normal.

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