Author Topic: Piston Failure Analysis  (Read 1360 times)

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Offline Cut4fun .

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Piston Failure Analysis
« on: December 12, 2012, 02:32:14 pm »
Piston Failure Analysis

Just a little guide to help people out.   In 2 links to read below in this post.
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Offline davbell22602

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Re: Piston Failure Analysis
« Reply #1 on: December 12, 2012, 02:40:27 pm »
Piston Failure Analysis

Just a little guide to help people out.   Should be 2 links to read.

Thanks for sharing that info.

Offline Cut4fun .

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Re: Piston Failure Analysis
« Reply #2 on: January 27, 2014, 02:11:17 pm »
What do you think?  Aftermarket P + C on 360 intake side.   He says  exhaust side looks good.  Ate something?  Says  crank bearings are not loose, but are not very smooth. 

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Offline jmester

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Re: Piston Failure Analysis
« Reply #3 on: January 27, 2014, 08:21:37 pm »
I would say ate some thing for sure. Would be looking on the flywheel side for what happen. I would lean toward a piece of the cage has came out.
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Offline Cut4fun .

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Re: Piston Failure Analysis
« Reply #4 on: January 27, 2014, 09:06:35 pm »
I would lean toward a piece of the cage has came out.

Thats what I was thinking.
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Offline jmester

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Re: Piston Failure Analysis
« Reply #5 on: January 27, 2014, 10:33:19 pm »
I say the flywheel side for the deep score by the ring lands on the flywheel side. Looks like it came up the lower transfer. But you are probably already ahead of me.
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Offline aclarke

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Re: Piston Failure Analysis
« Reply #6 on: January 27, 2014, 11:45:18 pm »
Bearings aren't smooth because of the crap they were fed.  Intake port shape is clearly evident in the damage profile on the piston.  Foreign object damage wouldn't be to concise

Offline KilliansRedLeo

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Re: Piston Failure Analysis
« Reply #7 on: January 28, 2014, 10:01:42 am »
Had a Jred 2171 that came in here a while back with almost identical damage but on the clutch side. Bearings rough also. Turned out that the ball retainer in the clutch side main failed. (Metal retainer not plastic) Got caught (I think) between the skirt and the jug on the up stroke more than once. Most of it was still in the crank well. Also scored up the bottom of the crank well.
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Offline 660magnum

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Re: Piston Failure Analysis
« Reply #8 on: January 28, 2014, 10:21:14 am »
My experience with the ball bearings is that the cage is the first thing to wear out. It is best to change the bearings before roughness or looseness failure because the damage the metal of the cage does. Even the plastic cages actually mess up the edges of the rings. So if you have a plastic Polymide cage failure, you should also replace the rings as you will find the edges to no longer be sharp.

Any high time engine should have the case split and the bearings and seals replaced even if you are just slipping ring(s) in it.

The higher rpm the engine is run, the faster the cage wears.
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Offline KilliansRedLeo

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Re: Piston Failure Analysis
« Reply #9 on: January 28, 2014, 11:11:10 am »
Agreed, 660!
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