Race Crank Balance

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perfconn
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Race Crank Balance

Post by perfconn »

How close are racecranks normally balanced? 1% over/under-10% over-under?
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Mark O'Neal
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Re: Race Crank Balance

Post by Mark O'Neal »

Normally? Depends on the opinion of the guy building it.
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SchmidtMotorWorks
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Re: Race Crank Balance

Post by SchmidtMotorWorks »

perfconn wrote: ↑Fri Dec 07, 2018 3:57 pm How close are racecranks normally balanced? 1% over/under-10% over-under?
The pro teams order lot's of them at once (because of long lead time) in bob-weight steps of about 20 grams.
They rarely balance them beyond that.

Still never heard of a good reason for overbalance.
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Mark O'Neal
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Re: Race Crank Balance

Post by Mark O'Neal »

Because 99% of engine building is opinion.
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Dave Koehler
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Re: Race Crank Balance

Post by Dave Koehler »

more like best guess. :wink:
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ijames
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Re: Race Crank Balance

Post by ijames »

SchmidtMotorWorks wrote: ↑Fri Dec 07, 2018 7:27 pm
perfconn wrote: ↑Fri Dec 07, 2018 3:57 pm How close are racecranks normally balanced? 1% over/under-10% over-under?
The pro teams order lot's of them at once (because of long lead time) in bob-weight steps of about 20 grams.
They rarely balance them beyond that.

Still never heard of a good reason for overbalance.
Or, to put it as a %, if the bobweight is 1500 grams then 20/1500=0.0133 or 1.3% so they can get within +/- 0.67%.
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Walter R. Malik
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Re: Race Crank Balance

Post by Walter R. Malik »

Mark O'Neal wrote: ↑Sat Dec 08, 2018 12:34 am Because 99% of engine building is opinion.
But, in crankshaft engine balancing that opinion is normally based upon RPM range to be run;
not whether it is to be designated "Race" or not.
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Re: Race Crank Balance

Post by Mark O'Neal »

Dave Koehler wrote: ↑Sat Dec 08, 2018 7:12 am more like best guess. :wink:

People seldom defend a "best guess" to the death.
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Re: Race Crank Balance

Post by Dave Koehler »

There is that.
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