[AT] Weird broken crank(not the 430!)

[Spencer Yost]

Base height and crank size and shape are critical:  the rest I can deal with.   The impeller required a crank that is tapered, keyed AND tapped to accept a bolt.   The height is critical because I would have to re-engineer  the impeller housing. 

I'll check out harbor freight and see if they have something that matches up.

Spencer Yost



Spencer Yost
> On Aug 2, 2017, at 2:52 PM, Dennis Johnson <moscowengnr at outlook.com> wrote:
> 
> Spencer,
> 
> Torsional Vibration is something I should have said in my first reply. The flywheel trying to smooth out torsional vibrations causes stress in the crank. A small imperfection can grow and grow until this happens.
> 
> Thanks
> Dennis
> 
> 
> Sent from my iPad
> 
>> On Aug 1, 2017, at 8:39 PM, Spencer Yost <yostsw at atis.net> wrote:
>> 
>> It's on a lawn vacuum, and it was running fine.  My wife was operating it so I didn't hear it.  She  said it just stopped, making a bunch of noise in the process.   The crack occurred right behind the bearing, inside the crankcase at the flywheel end, not the impeller end.
>> 
>> There was a good level on the dipstick and an oil change in the winter so it was not oil related.
>> 
>> Spencer Yost
>> 
>>> On Aug 1, 2017, at 9:05 PM, vschwartz1 at comcast.net wrote:
>>> 
>>> Spencer; I do not have any real knowledge about this kind of break but it would appear to me that one side or the other would be smooth. I simply have a case of nose trouble. What was the engine doing when the crank broke? Was the break at the throw? For both pieces of the crank to be like that photo looks I would think there must have been some end play. Maybe that is a normal thing, now define normal. 
>>> Just wondering, 
>>> Gil 
>>> 
>>> ----- Original Message -----
>>> 
>>> From: "Spencer Yost" <yostsw at atis.net> 
>>> To: at at lists.antique-tractor.com 
>>> Sent: Tuesday, August 1, 2017 6:04:09 PM 
>>> Subject: [AT] Weird broken crank(not the 430!) 
>>> 
>>> I have a small Briggs that broke a crankshaft yesterday. The weirdest thing I've ever seen. Have you ever seen a crank break and leave this type of a star pattern on both ends? 
>>> 
>>> 
>>> 
>>> [image/jpeg:image1.JPG] 
>>> 
>>> 
>>> 
>>> Spencer Yost 
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