Rod bearing question

Discussion in 'PSI Superchargers Tech Questions' started by Kongen pa Mona, Mar 10, 2020.

  1. Kongen pa Mona

    Kongen pa Mona New Member

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    Hi
    Anyone that knows why my rod bearings look like this?
    It is just the 3,5 and 7 rod bearing.The rest of the bearings is just fine
    its a blown alcohol chevy 496 with 10/71 blower makes around 24 psi
    Brooks alu rods
     

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  2. JNR

    JNR TA/FC

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    How many runs on the rods ?
     
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  3. jay70cuda

    jay70cuda Active Member

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    The radius on the cranks isn't the same as the even side would be my guess. I've seen that before.
     
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  4. Kongen pa Mona

    Kongen pa Mona New Member

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    I have about 40-45 runs on the rods and the upper half of the bearing is fine
     
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  5. JNR

    JNR TA/FC

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    Get a new set of Rods and you are Good !
     
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  6. Ryan D

    Ryan D New Member

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    Mine do that to on my hemi. Never came up with a definitive answer, I checked all clearance’s and oil pressure is good. I’m chocking mine up to crank flex it’s the only thing I can think of that makes sense. This is the lower after 20 passes.

    85892A3B-4839-41F6-AFC5-9D2FCA34065E.jpeg
     
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  7. Kongen pa Mona

    Kongen pa Mona New Member

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    I got a tip to use softer bearings for the rods, so I will try that. I m running clevite 743 hxnd now,and I will change to king bearings
     
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  8. Ray Hadford

    Ray Hadford New Member

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    HI Ryan D ......... Is your bearing issue possibly Methanol corrosion? Does not look like a wear issue to me.....

    I have seen the same thing in my supercharged methanol small block.

    I am long way from the worlds expert on bearings.....
    Someone else please jump in.

    Ray H.
     
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  9. Ryan D

    Ryan D New Member

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    Ray Hadford, And I guarantee I’m further away than you lol this is only my second year with a blown alcohol combo. First year with me as the builder.

    I had forgotten that someone else had stated Methanol corrosion for my issue as well. And thinking about it, you are probably right, seeing on how I run 14 quarts in a wet sump application. I’m sure my crank and rods are floating in 70wt and methanol between races. I’ll try draining the oil between races to see if that helps or if it goes away completely. Thank you for your help.

    Kongen pa Mona: I too am going to try a softer bearing, as I was running an H as well.
     
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  10. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    I would recommend the Clevite V bearing over the King. I think the King is going to be too soft for extended use between bearing checks.

    Also softer bearings won't fix whatever the real problem is. It appears the clearance is tighter in those spots which could be the rods or could be the crank.
     
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