Crack in Piston on Rebuilt Engine -How Could this happen?

I am reminded of my freshman Calculus 101 professor. Dr. Satinder. This was the first or second week of classes and I was one of a couple of hundred students in a large lecture theatre. After waving with sufficient animation to capture her attention I said “I don’t understand what you just did there” to which she replied “I don’t understand why you don’t understand.” This was her first year teaching after having secured her PhD and her failure rate at the end of the second semester was sufficiently high that she was not invited back.

Sometimes the most brilliant experts make the best teachers. Sometimes not. Teachers achieve the most indelible learnings when they guide their students through a process of error and discovery, rather than reveal the answer from the get-go and simply expect them to accept it.

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I was wondering about the vertical wall scratches as well

Based on my learnings from this thread, a wipe with acetone will remove these…
How’d I do?

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Hi Graham When I first saw your photos I initially thought that the deposits were such that those were not new pistons, but then you said the engine was broken in on a dyno, so I didn’t think any more about it. How long was the engine run on a dyno before you took these photos? Ignore this question if you like, I don’t want to raise irrelevant issues, just curious. I’ve seen a fair number of deposits that have an abrupt ragged edge like yours that I also thought were cracks (none ever were) but it’s always been on somewhat aged pistons. By the by those deposits were very hard to remove.

Well, If you’re Scandinavian and have run out of Birch branches….

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Colin Chapman must have worked on the design for his use. :roll_eyes:

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Brings to mind the classic piece from Car Talk, still a legend in discourse:

https://www.cartalk.com/radio/letter/andy-letter

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I don’t have the actual run time but I do know it was only about 10 minutes in NZ and however long it take to tune an engine in Australia.
I guess only an hour or so. I shall try to get more accurate hours just for my own information. The deposits on this engine were relatively easily removed in about 10 minutes of acetone scrubbing.

When you got it off did the “cracks” disappear?

The cracks did disappear much to my delight - see my photos on post 64

Sorry the reply was meant for Terry
The cracks did disappear much to my delight - see my photos on post 64

All right!!! plus 20 or more characters

I appreciate the high resolution of your photos. Tell us a bit about the endoscope used. Medical quality? Make/model?

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It is a cheap one bought on ebay for about $AUD62 and it interfaces perfectly to my apple phone.

Mine is the yellow version -I don’t know the difference to the blue sold to USA.
Great value and it did the job for me.

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Certainly the best-looking boroscope pictures I’ve seen.

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It was a bit boring in the total scope of things to be seen and wasn’t as cracked up as it was supposed to be. :roll_eyes:

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Larry, back away from the keyboard, and lighten up on the turps.

:stuck_out_tongue_winking_eye::smiley::rofl:

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What’s a turp??
Is that like a yoot? ← HEY, I needed 20

Aussie slang for booze…:laughing: