combustion chamber profile for pump petrol road

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fred
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combustion chamber profile for pump petrol road

Post by fred » Sun Mar 04, 2018 3:54 am

hello, i came across a old cylinder head i did`nt know i had ,but one side has been mullerd by a ring snapping ,my plan is tig it up and chuck it in the lathe and re profile it ,because of distortion if there is anything i can do to both while i`me at it maybe ,then i can do all the welding and skim it , So from a standard head profile is there anything worth changing ,pump petrol road use ?

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JanBros
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Re: combustion chamber profile for pump petrol road

Post by JanBros » Sun Mar 04, 2018 11:21 am

it all depends a bit on the timings of your engine, and whether you want high power, more midrange, ...

http://users.telenet.be/jannemie/JanBro ... 0Calc.xlsm

squish area 40-50%, high revving engines/power more like 40.
squish height minimum 1% of stroke, but to be on the safe side I use 0.7mm
compression ratio : the higher, the more energ is used to push the piston down, but the less energy that remains for the pipe to do it's work. higher compression = more mid range.
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