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Dodgeman |
Posted: 2004/7/23 15:15 Updated: 2004/7/23 15:15 |
No life (a.k.a. DattoMaster) Joined: 2003/6/27 From: Southern Tablelands N.S.W. Australia Posts: 8287 |
Re: The other end If this rod had been lightened, just a little, by following the process outlined in the factory manual [see other photo], then there is every reason to believe that this engine would be alive today.
Polishing the beams removes surface irregularities that can be the source of these fatigue cracks. If there are any surface scratches remaining, created by the polishing process, they should be "along" the beam, which is OK, it's the ones that are across the beam that cause the real grief.
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Dodgeman |
Posted: 2004/7/21 13:24 Updated: 2004/7/21 13:24 |
No life (a.k.a. DattoMaster) Joined: 2003/6/27 From: Southern Tablelands N.S.W. Australia Posts: 8287 |
Re: The other end Does that look like a fatigue crack to you?
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who_your_datty_1200 |
Posted: 2004/7/21 13:29 Updated: 2004/7/21 13:29 |
No life (a.k.a. DattoMaster) Joined: 2004/2/26 From: Posts: 1440 |
Re: The other end that would be the smooth part rite??
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Dodgeman |
Posted: 2004/7/21 13:33 Updated: 2004/7/21 13:33 |
No life (a.k.a. DattoMaster) Joined: 2003/6/27 From: Southern Tablelands N.S.W. Australia Posts: 8287 |
Re: The other end None of it is actually "smooth" but there are two distinct colours & a very obvious line between them. Perhaps i should have a real good look at the real thing tomorrow.
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who_your_datty_1200 |
Posted: 2004/7/21 13:44 Updated: 2004/7/21 13:44 |
No life (a.k.a. DattoMaster) Joined: 2004/2/26 From: Posts: 1440 |
Re: The other end I see what you mean now, very distinct line, just had to open my eyes a bit wider.
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feral |
Posted: 2004/7/21 14:04 Updated: 2004/7/21 14:04 |
Home away from home Joined: 2002/5/1 From: Millgrove Vic OZ Posts: 985 |
Re: The other end The left side centre of the rod has a discoloured area that was originally a small corroded area or bump on the surface. I reckon this has been a stress raiser and started the rod cracking here. It eventually opened up the crack over time till it reached the right side straight line where it had little support left and it opened with a bang.
If any one is interested in this sort of stuff, Caterpillar have a very good course in failure analysis for their diesel engines. It applies to small petrol engines equally as well I think.
This is an example of why race engines used polished beams and shot peened rods.
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woodydat |
Posted: 2004/7/21 14:52 Updated: 2004/7/21 14:52 |
Home away from home Joined: 2004/1/29 From: Posts: 966 |
Re: The other end wat does shot peenin do and wat does polishing do..i thought it made the rod stronger
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holeshot |
Posted: 2004/7/23 11:12 Updated: 2004/7/23 11:12 |
Home away from home Joined: 2003/4/29 From: GOLD COAST AUZ Posts: 360 |
Re: The other end YEP that is a stress crack.Makes you think a bit harder about lighting rods.
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