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HybridZ

Better to buy a new crank than to have the old one turned down?


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I'm finally getting stuff going with both engines and I was just going to throw a new set of bearings on the 350 (vortec) but I noticed the crank was scuffed up a little. I took it to the machine shop and he said it needs to be ground down. So I'm wondering, can I just buy an OE (or maybe better) crank that I won't have to balance and how much and where? How much does it usually cost to grind a crank down? Thanks :D

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If you can get away with a .010" grind an polish you can use easy toi find oversize bearings and probably not have to re-balance. That should be cheaper than a new crank. But... if you want to upgrade to a forged crank, lighter rods, new pistons, or a 383 stroker kit, this would be the time to do it, and re-balance it all togther as a rotating assembly. Depends on how fast you want to spend (to steel a quote from another member).

Steve

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There are different "types" of shops. Joe schmoe shop will grind it .010 - .010. A good shop will ask you if you want it index ground, what bearing clearance you want, ie. ground on the low side, split, or the high side, which should give you .001, .0015 or .002 clearance and what chamfer you want. They will also chamfer the oil passage holes. Don't accept a grind that doesn't include chamfered oil passage holes!!!!! A grind shouldn't effect the balance much although it will some, since the thicker bearings weigh less than the crank material or visa versa. Anyway, don't sweat it, it's not that big of a deal.

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Wow! This thread went from a scuffed journal to a metalurgy discussion. You guys do get deep into these topics. I thought I was the only guy crazy enought to offset grind cranks for more stroke, have radiuses machines between the journal and counterweight face to eliminate stress risers, and buy special radiused bearings... in other words, let my project budgets spiral dangerously out of control because fast enough and relaibale enought, never is. You guys are as demented as I am.

Steve

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"You guys are as demented as I am"

 

 

IM PROBABLY FAR FURTHER DOWN THE PATH TO THE LOONEY BIN IN MY CASE, SIMPLY BECAUSE I LOST COUNT OF THE ENGINES IVE BUILT ABOUT 10 YEARS BACK AT A TOTAL OF OVER 150 SOMETHING.........THAT MAY SOUND LIKE A BUNCH BUT OVER 38-39 YEARS IVE BEEN BUILDING THEM SEMI PRO, AS A SIDE BUSINESS ITS NOT THAT MANY A YEAR, SOMETHING LIKE 6-9 A YEAR

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Thanks for the encouragment! After 8 over years, I'll be finished putting three kids through college in about three more months. That alone will give me a $10,000 increase for next year to fuel the budget for my hobbies. Of course, after taxes, and after splitting what's left with my wife, I'l still only have about $1.49 to spend on cars.

Steve

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