combustion chamber questions

[B Thomas]

I am building a pair of 82 Power Products .
When doing these to raise the compression you cut the top off of the blind cylinder and make a replacement head .
Since there are no tech rules in vintage karting The chamber design is open .
I am using 820 West Bend pistons and they have a bit of a dome .
The jugs are ported and booster ported .







I will be running alcohol and open exhaust stack .

I am unsure what else needs to be taken into consideration when designing a chamber .

I have the blanks made for the heads





My question is what kind of chamber would you design.

Any input would be great.

Thanks

Brian
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Brian and Dottie Thomas
Black Dog Vintage Racing
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[Walt Gifford]

Cut the squish band at 17 degrees, make the squish area 45% of total bore area and cut a bee hive shaped combustion chamber until you have a 10:1 compression ratio. Although looking at that head blank I'm not sure you'll have any threads left for your spark plug. I would have left the plugs gasket seat cut for last. You want at least 1/2" clearance from your plugs ground strap to the piston.

Nice job squaring out the exhaust ports, the crack of that exhaust note should sound awesome with no muffler.

Gif
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FAA certified jet engine and aircraft technician
Nicholson Speedway class champion 2001
Yamaha KT100 Service Center
40 years karting experience

[al nunley]

I think McCulloch had it pretty close to right, try it their way.
My personal experience is it makes little difference. There are 2cycle engines out there with just a dome and no squish. The compression ratio, above the exhaust port, (called the effective compression ratio) is what is important.
Running stacks, instead of pipes, means it makes little difference.
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If the data does not support the theory, get a new theory. (Al Nunley)
All else being equal; Compression is the Holy Grail.
45 years, in and around karting