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  #1   IP: 67.241.137.168
Old 09-06-2018, 09:49 PM
jkaiser77 jkaiser77 is offline
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Nicks in Cylinder Walls

Hi folks

Finishing up my first overhaul - a fun/fascinating/frustrating experience. Thank you to everyone who has offered advice along the way.

Had the cylinders rebored (0.010) by the local machine shop. The job was supposed to be done last July, but wasn't done until November, and I couldn't pick it up until this July.

When I picked up the block there were a few tiny black spots in the cylinder walls, which I assumed were just dirt or carbon I could clean with carb cleaner. When I did clean them, just before installing the pistons, I found some small nicks (see photos). My fingernail catches on them.

Is this a problem? If so, how big?



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  #2   IP: 99.30.185.198
Old 09-06-2018, 11:36 PM
thatch thatch is online now
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In a "perfect" rebuild, we would like to see cylinder walls with a good cross-hatch pattern and no nicks. In the case of an A4 re-bore, I feel that water jacket thickness trumps a few minor blemishes. I"m pretty sure that with this low compression engine you will not experience any loss of cylinder pressure or see more oil burning. I feel that your machinist made the right decision.
Tom
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  #3   IP: 137.200.32.22
Old 09-07-2018, 08:47 AM
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Are we assuming those nicks were already there and the machinist did not want to overbore too much attempting to get rid of them?
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Old 09-07-2018, 09:36 AM
jkaiser77 jkaiser77 is offline
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Not sure if the nicks were already there or not.
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  #5   IP: 99.30.185.198
Old 09-07-2018, 11:27 AM
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In the upper photo there appears to be some more smaller pits just to the right of the highlighted area. I suspect that all of these pits were caused by water sitting in the cylinders for quite some time.
Tom
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