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-   -   Here is a dumb question about a cranshaft (http://forums.pelicanparts.com/porsche-911-technical-forum/846584-here-dumb-question-about-cranshaft.html)

ChrisP911 01-13-2015 10:22 AM

Here is a dumb question about a cranshaft
 
I had my crankshaft checked out, Today I get a call that it is cracked at the first two rod journals are cracked. So the dumb question is can it be re-welded.

Hil911 01-13-2015 12:47 PM

If it were mine, I wouldn't. That's based on my feeling rather than knowledge.

It seems to me that cracks result from two causes: fatigue (thermal or mechanical), or brief, extreme stress events.

Either way, cracks concentrate stress which is why they propagate. Similarly, I really doubt whether a weld could either close up a deep crack or not itself allow stress concentration. And the crankshaft has provably already had a hard life. There are two cracks but it's hard to believe that the rest of the crank is in virgin condition.

If I welded the crank, I would be just waiting for it to fail again, every time that I pushed it.

Hil

ChrisP911 01-13-2015 01:45 PM

that's what I thought. I called 5 machine shops and they said no go.

ChrisP911 01-13-2015 01:45 PM

So it just scrap metal.

Bleedsblue 01-13-2015 02:00 PM

I would call it expensive art.

TimT 01-13-2015 02:06 PM

Quote:

So it just scrap metal.
Pretty much. What engine is the crank from? You can get good used cranks, measured and cleaned for not to much dinero from a number of sources...

irl 01-13-2015 06:49 PM

http://forums.pelicanparts.com/uploa...1421207377.jpg

ChrisP911 01-14-2015 10:48 AM

Love the lamp Idea


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