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66mm crank question

I am looking at a 66mm std/std crank that has 1 journal that's been welded. I'm planning to use it eventually to build a 2.5 liter short stroke motor on a 7R crankcase. Should I be concerned about the journal that's been welded?
Thanks!
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Old 03-02-2006, 05:57 PM
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Yes, especially in a SS-2.5, where it should be a very high-revving engine.

You may develop cracks near the welded journal. The higher it's revved, the greater the harmonics acting on the crank, and the greater potential for failure.

If it's just going to be a street motor, it may be O.K., but I wouldn't risk it. Never go cheap on major internal parts that could potentially destroy the entire engine.
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Old 03-03-2006, 09:58 AM
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Tyson, What is your opinion on the CW vs non-CW 66mm crank for a 2.5 motor? I have seen some that say the CW is stronger and that the non-CW spins up faster. This would be for a non-full race motor but one that would see multiple track events/year.
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Old 03-03-2006, 10:02 AM
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I have a 66mm CW crank that is 1st undersized (.25mm) on both rods and mains if you need one.

I also have a 3.0 crank 1st undersized on rods and mains if anyone needs that as well.

Regards,
Andrew M
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Old 03-03-2006, 10:21 AM
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Thanks for the input Tyson!
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Old 03-03-2006, 10:41 AM
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Quote:
Originally posted by jpnovak
Tyson, What is your opinion on the CW vs non-CW 66mm crank for a 2.5 motor? I have seen some that say the CW is stronger and that the non-CW spins up faster. This would be for a non-full race motor but one that would see multiple track events/year.

It's true that the non-counterweighted crank will spin up faster. The advantage of the counterweighted crank is bearing longevity, and reliability long-term. If you run the non-counterweighted crank, you need to rebuild more often, and be very dutiful on your inspections.
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Old 03-03-2006, 12:09 PM
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Quote:
Originally posted by andrew15
I have a 66mm CW crank that is 1st undersized (.25mm) on both rods and mains if you need one.
Do you also have the bearings to fit it?
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Old 03-03-2006, 02:39 PM
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No, I don't have the bearings, but they are available new from our host as well as others.

AM
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Old 03-03-2006, 03:38 PM
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1st over bearings for a 2.2 crank are easy to find.

If done properly a first under crank should be no problem.
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Old 03-06-2006, 08:57 PM
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