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Repairing the damaged cylinder

This is a close up of the damage to the cylinder, and you can see the broken valve head has caused some nasty impacts, so I decided to scrap the cylinder.

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As these are all in one cylinders and heads, as in very deep, it's a mess trying to get down to weld and machine afterwards, and I thought it wasn't worth the effort. I found another cylinder that was a similar size with the liner removed, and I will update this.
First up I had to make a jig for the CNC machine to hold the cylinder in the desired position, and so a flame cut lump of metal was ordered, then I needed the dimensions for the CAD model,and this is where a Faro arm comes in..

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Next up a partial twin plugged cylinder had the standard exhaust seat removed as a precaution, as well as the valve guide later on. Notice all the deposits that oozed out of the seat removal process, which tells you this one was loose.

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…and after a clean, and you can seat the exhaust valve seat recess fretting marks…

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Now to create a test piece, to double check the accuracy of the jig, which had been CNC'ed from the CAD model I drew up previously.

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Then time to double check the accuracy on the Faro again, but this is now September 2014. I have been working on other stuff whilst trying to progress this.

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Another check a few weeks later, to make sure the milling machine can reach the bottom of the combustion chamber.

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After all this there was a twist in the jig, and it needed to be machined, but at least it was spotted before any cylinders were done.

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Finally in early December 2014, it is time to machine the new valve seat recess in the combustion chamber.

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Then a quick check of the seat size, and a tweak to the final cut.

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…and this is the finished seat recess cut into the head, with concentric valve guide hole done at the same time too.

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After Christmas, it was time to make the guides and other stuff.

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