Spun bearing on fairly fresh rebuild

Discussion in 'Street/strip 400/430/455' started by Kyle Knautz Jr, Jul 17, 2019.

  1. Kyle Knautz Jr

    Kyle Knautz Jr New Member

    I rebuilt my engine last year 455 bored .030 over crank polished new main and rod bearings stock rods upgraded to hypereutectic 9.5:1 pistons ta performance 284h cam and lifter stock rocker arms and push rods. Edelbrock intake and edelbrock 750 carb. When i first put the engine in it felt like it was faster stock until i had the distributor recurved. Ever since then its ran twice as good. In early may i was on my way to a car show 2 1/2 hrs away and my engine started knocking. So long story short i took it to a shop nothing but metal shavings and copper in the oil and filter. The engine had 3500 miles on it and was running great until then. I was just cruising down the highway taking it easy i don't understand how it happpened. But it never had the sound i was looking for and depending on what is salvageable on tje bottom end what should i do to get that nice street strip exhaust note (hemi killer)! I still have to pull my motor and take it to a shop to see exactly what went wrong. The only thing i van think of is that i possibly over revved it or one of my connecting rods needed reconditioned and i used the same bearings on all the rods? So still trying to budget but not afraid to spend a little on parts if i will see and hear a gain in performance what would you buick guys recommend? Any info would be greatly appreciated thank you for listening!
     
  2. 72STAGE1

    72STAGE1 STAGE 1 & 2

    Better heads, roller cam and rockers and 800 cfm carb
     
  3. alain

    alain Well-Known Member

    :)Take it to a reputable engine shop and have them do the rebuild.
    Cost a bit more but you won't do it twice.
    Alain:)
     
  4. Stevem

    Stevem Well-Known Member

    If it was a Rod Bearing that spun and If during the rebuild the rod bolts where not changed and the rod big end resized to the minimum spec for good Bearing crush then there you have it if it was only one Rod that went south!

    My rule of Thumb is that in a performance motor the Rod and main bolts should get replaced after every 4 torque up session for safety sake otherwise you stand a really good change of them going rubber on you , and even more so with the stock factory Rod bolts!

    In short if you do not know the history of the Rod and main bolts then error on the safe side and replace them, or in the case of how cheap and strong new Rods are , then replace them.

    Also if you assembled the bottom end did not torque up the Rod bolts by the preferred stretch method then that could be the failure point right there!

    Please note that with stock iron heads on your motor your not getting anywhere close to the low ball rated 425 hp that a Mopar street Hemi of yore had!
     
    Last edited: Jul 18, 2019
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Do you have a real oil pressure gauge?
     
  6. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Too many variables to say what went wrong. We can all guess but it won't get you anywhere.

    What you can do is educate yourself some and make sure its done proper this time.
     
    Schurkey likes this.
  7. GlenL

    GlenL I'm out in the garage

    Sounds like a rod. I'll be interested in what it looks like when it's apart.

    Were the bearings plastigauged on installation?
     

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