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Old 12-10-2011, 12:14 PM
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Default broke driveshaft imco ext box?

Has anybody broke a driveshaft in a imco ext box.I will be putting 1200-1300hp thru it. Im just worried about the extra length shaft being weaker then a short standard shaft.
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Old 12-10-2011, 02:36 PM
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Ive been running imco scx drives for years with 1300hp to each drive and I've never had a problem with anything breaking above the lower drive.
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Old 12-10-2011, 02:39 PM
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and thats with extension boxes and the longer driveshafts. as long as you keep the u-joint and coupler well greased you shouldn't have a problem. Its not a common breaking point. Most guys will have drive gear failure long before seeing the driveshaft break.
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Old 12-10-2011, 09:33 PM
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I think the longer input shaft gives it a lttle "torsional" cushion, Smitty
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Old 12-10-2011, 09:35 PM
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Originally Posted by articfriends
I think the longer input shaft gives it a lttle "torsional" cushion, Smitty
yes i agree, having a little flex will save parts from breaking, you will have a drive failure long before you have 1 of those shafts break.
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Old 12-10-2011, 11:34 PM
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Thanks for your guys input.This would be the new style xr joints on a scx drive.
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Old 02-03-2012, 12:08 AM
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The one part I've never broken is the Imco extension box shaft. Honestly shocked that I haven't yet actually...
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Old 02-03-2012, 02:54 AM
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Before upgrading to XR shafts, I did break a std u-joint(1.077cup) IMCO shaft right in the middle where the old shafts tapered to a pretty small diameter.

The new XR shafts are a lot beefier, with no taper. As mentioned, probably not a weak link.

With that said, when I broke my port helmet in Oct(picts on pg4 of the broken transom plate thread), I did however bend the XR shaft. I mounted an old gimbal bearing in a vice and spun the shaft in it, and the splined end has at least 1/2" of run out.

LE
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Old 02-03-2012, 05:54 AM
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I was told at one time to make sure there are no nicks in the shaft, causing a weak point. But I have not heard of any failures. I just installed the new one for the SCX and it is a beefy unit.. I wouldnt worry about it.
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Old 02-03-2012, 06:54 AM
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We broke one in the Svl with 550 HP. It had over 10,000 miles on it and was 4 years old. It broke about 4-5 inches north of the U joint.
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