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Sunday, September 20, 2015

dorkpunch engines #3: Boring the cylinder.

I had some time to kill at the shop while waiting for my wife. She said she would be over in half an hour, which of course means 2 hours. She even ran a little late so it was more like 2 and half so I was able to knock some holes in some aluminum.

1/8" pilot holes, 3" deep through the cylinder. The two for the valves are the finished diameter for the valve guides. The cylinder has a long ways to go... 7/8" more to be exact.

To drill them I had to use a big 'ole aircraft drill. Started with a normal drill bit, got as deep as it could go, then switched to this long one. Figured there was less chance of the holes going crooked on me.

Makin' chips.

Makin' BIG chips...

and big messes.

"Finished" cylinder. The drill bit is obviously a bit rough, so I plan to hone it with a brake master hone and then match the piston to the finished bore.

Because of the vice I was using, I couldn't drill all the way through. This is not a problem though, because I still need to machine off about 1/4" to get it down to the stroke I want.


Will hopefully start doing some figuring on where the valve ports need to go and the final diameter of the valve heads.

Thinking I should have left the bore a tad smaller- its pretty close to some of head bolt holes. Won't have a lot of gasket area in those two spots.

Live and learn...

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