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Chamfering crankshaft oiling holes?

Discussion in 'The Garage' started by y5mgisi, Jan 9, 2005.

  1. y5mgisi

    y5mgisi 1 ton status

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    I have heard that this is a good thing to do. The 350 im rebuilding does not have the oil holes chamfered. My question is should i chamfer them and should i do it myself? I have a dremal but what bit should i use? Is it realy important to do this or is it an old engine builders tale?
     
  2. beater_k20

    beater_k20 Banned

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    it is definitely a good hing to do, as it improves oil flow through the crank. you might also look into porting your rear main cap, where the oil pump feeds into the system.
     
  3. RustBuket

    RustBuket 1/2 ton status

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    I dunno about doing it yourself tho? You wouldn't want to scratch up the journals. Even the dremel could leave an edge on the crank.
     
  4. y5mgisi

    y5mgisi 1 ton status

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    What about just using a file? Tell me more about the rear main cap porting.:ears:
     
  5. beater_k20

    beater_k20 Banned

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    i've got a book by David Vizard that tells indetail how to do it, and why to do it, along with pics. i'll scan them later.
     
  6. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Whats the book called?
     
  7. wasted wages

    wasted wages 3/4 ton status

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    my .02

    Spend a few bucks and have the crank cross drilled and the oil holes chamfered
    and the journals micro polished by a reputable crank shop. It's money well spent. For those that don't know,,cross drilling the mains will allow the rod journals to be fed oil a full 360 degrees of crank rotation. Most standard OEM or low performance cranks only lube the rod journals every 180 degrees.

    Your bearings will love you for it !!:saweet:
     
  8. R72K5

    R72K5 Banned

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    what diameter hole/bit ?
     
  9. sled_dog

    sled_dog 1 ton status

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    whatever one the machine shop you take it to uses :D Not something I'd say the do it yourself should do unless they have a good deal of engine building experience. I know I wouldn't do it with a hand drill or standard drill press/vise setup.
     
  10. mudjunkie 82

    mudjunkie 82 1 ton status GMOTM Winner

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    I would just take it to your local machine shop and have them do it. It should not cost very much. All it would take is one burr on an edge and there goes your motor rebuild.
     
  11. ntsqd

    ntsqd 1/2 ton status

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    Likewise, I'd also advise letting the machine shop do the chamfering & possible cross drilling. If you lunch it, it's your dollar. If they lunch it, it's theirs.

    The object of the porting of the rear main is to smooth the transitions in the oil flow. Oil, like a lot of things in life, doesn't like sudden changes in direction. This you can do with a dremel though it will take a while. Don't get carried away removing metal. Just carefully blend over and round off all of the edges in the oil cavity EXCEPT those where the oil pump body fits against the main cap.
     
  12. y5mgisi

    y5mgisi 1 ton status

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    Mabey i'll do some calling around tommorow then and see what people are wanting to do that. BTW do you think 190 dollers is to much or a good deal for an engine block prep(including hot tank, check for cracks, bore/hone, cam bearings, and freezplugs)?
     
  13. POWERMAD

    POWERMAD 1/2 ton status

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    That's about the going rate rate for machine shops in the area.

    It's $90 just to have the block cleaned and magged, $100 to have it bored with the cam bearings and plugs installed isn't bad at all.

    It's all the other stuff that since it there that start rackin up the $$$.
    There is a shop over in Vancouver that does realy nice work and they have pretty reasonable rates. I can get ya the # if ya want it.

    I was quoted $175 to have the rotating and reciprocating assy's balanced.
    Damper,crank,flywheel/flexplate, pistons and rods.
     

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