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Crankshaft straightening


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#1 ol' stonebreaker ONLINE  

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Posted November 24, 2015 - 03:58 PM

  Tried this as I read about it being done a couple of yrs ago. Sorry, no pics so I guess It didn't really happen. Drained oil, set it upside down on some milk crates(boy those are handy) and strapped it down to them. Removed blade and hub, slipped a piece of 1" pipe over the shaft and whacked w/ the 8 pounder until I couldn't see the runout . tacked a piece of flatbar to the deck for the  dial indicator's magnetic base to stick on and worked on it w/ pipe and 2 pounder until I got it down to about .008" runout. Reassembled, filled w/ oil and fired it up. Seems as smooth as any other push mover I've had. Sitting running in the yard now to see if crankshaft is going to break. What surprised me was the crank had about 1/4" of runout but it didn't bend the blade.

                                        Mike 


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#2 boyscout862 ONLINE  

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Posted November 24, 2015 - 04:28 PM

Great backyard mechanicing. I picked up one of the professional straighteners at a tag sale 15 years ago. It is very precise but I'm not sure its worth it. They sell for big bucks at some of the dealers. Sounds like you have the cheap solution. Good Luck, Rick 


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#3 Lmiller3358 ONLINE  

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Posted November 24, 2015 - 06:25 PM

Nothing like a little persuasion !


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#4 Bruce Dorsi OFFLINE  

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Posted November 24, 2015 - 06:44 PM

I have found that the worse the crankshafts are bent, the easier they are to straighten.

 

Of course, this applies to the longer crankshafts. 



#5 Bmerf ONLINE  

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Posted November 24, 2015 - 07:00 PM

Did it blow up?



#6 dthomp17 OFFLINE  

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Posted November 24, 2015 - 07:25 PM

From your description, I'm assuming the crankshaft was not removed from the engine before straightening. How did you manage to not damage the crank bearings or cracking the engine crankcase while pounding with the 8 pounder?



#7 chieffan ONLINE  

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Posted November 24, 2015 - 08:10 PM

Nothing like instant impact.  My Uncle, a German immigrant blacksmith had a saying;  "If it ain't broke, get a bigger hammer"



#8 ol' stonebreaker ONLINE  

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Posted November 24, 2015 - 10:10 PM

Did it blow up?

  Nope, it ran for about 45 min full speed until it ran out of gas. No evidence of cracks or oil leaks.

                                                 Mike


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#9 ol' stonebreaker ONLINE  

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Posted November 24, 2015 - 10:10 PM

From your description, I'm assuming the crankshaft was not removed from the engine before straightening. How did you manage to not damage the crank bearings or cracking the engine crankcase while pounding with the 8 pounder?

  Luck, I guess.

                         Mike


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