Scratches on inside of cylinder head combustion chamber

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kevock1950
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Scratches on inside of cylinder head combustion chamber

#1

Post by kevock1950 »

I recently bought a "freshly rebuilt" motor with repop Vtwins cylinder heads installed...

I popped the heads off to look in the cylinders to determine freshness of rebuild and to inspect heads. I found that the front cylinder head combustion chamber had some scratching in one area that didn't appear like it was caused by the casting process, but I cant be sure. This scratching was not near edge of combustion chamber or anywhere near a valve pocket. But, I removed valves to see if there were any issues with a bent or cracked valve(s) (although these heads truly were as advertised and are brand spanking new). I couldn't determine any problems or issues with valves nor is the piston hitting valves or the combustion chamber.

Before anyone recommends I throw these heads into the trash or swap for OEM ones, I am determined to make these work...

So, should I lightly sand out the scratches, or can I leave the scratches alone? Do I just take off the "high spots" in the scratches?
If I sand them, what do you recommend sanding with?

Thanks in advance for any ideas or information...
1950Panhead
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Re: Scratches on inside of cylinder head combustion chamber

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Post by 1950Panhead »

Sand the scratches out if it makes you happy, use 220 wet/dry.
kevock1950
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Re: Scratches on inside of cylinder head combustion chamber

#3

Post by kevock1950 »

Is it necessary though?
old.wrench
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Re: Scratches on inside of cylinder head combustion chamber

#4

Post by old.wrench »

kevrock,
You don't need to completely sand out all signs of the scratches; don't go crazy with the sandpaper :) .
As long as you knock down the projecting tips of the high spots (if there are any) you should be O.K.
The main concern is with any thin curls or shards that stand proud of the surface and have the potential for heating up and causing pre-ignition.

Geo.
kevock1950
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Re: Scratches on inside of cylinder head combustion chamber

#5

Post by kevock1950 »

Thanks, Geo...

I went ahead and lightly sanded with 220. I knocked them down just enough to ensure there are no high spots...I feel good about the result.

Question is...how did they get there? I guess I wont know.
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Re: Scratches on inside of cylinder head combustion chamber

#6

Post by james »

A picture of the combustion chamber before you sanded them might help to identify.

Jim m
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