Hi,

Im trying to find a formula for cylinder head internal height:
How much Height do I need to leave left while cutting down its height, yet still be able to make enought volume, but based on factors like:
50% of areal squishband
50% of areal combustion chamber
A set diameter (47mm)
Both squishband and combustions chamber gonna be at a certain compression level, squishband is sometimes taller in the center than in its outer edges("hemi top") and sometimes there are added triangular cuts in the cylinders squishband towards the sparkplug which goes deaper and deaper the more close to center.

My stats:
Rod lenght (L) = 80mm
Half stroke/Radius (R) = 18,9
Clearance = 0mm
Cylinder diameter = 47mm
Distance from cylinder top to eksosport roof = 16,5mm (207,75°)
Distance from cylinder top to transferports roof = 27mm (142,52°)
Piston heigh intake side: 43mm
Distance from cylinder top to intake floor = 64mm (179°)
Squishband height = 0,4mm outer edges , and its centered "dome" would have been 3mm higher but then ur already in combustion chamber.
Squishband = 50% of areal 867,47mm^2 aka 8,309mm wide each side.
Combustion chamber = 50% of areal 867,47 aka 30,38mm wide inner circle.
Dynamic comp = 9,36:1 and 3,42ml / cc

I use theese formulas which can be built upon/used, but somehow i feel this is pure volume of dome calculations.. :
D = Duration (given in deagre of shankshaft rotation)
R = Half stroke
C = Dead clearance
E = Distance from cylinders top to exaustport and transferports roof
H = Piston height (intake side)
F = Distance from cylinders top to intakeport floor
T = R + L + C - E
D =(180-ACOS((T^2+R^2)/(2*R*T))*180/PI)*2 <- I multiply with 180 and devide by PI to get in degreas, due to the fact excel works in radians.

Blowdown = (exaust duration - transfer duration) /2

CC = Cubic
Suggested carbourator size = 0,85 * SQRT (PeakRPM * ( CC / 1000))

Areal cylinder = PI * (Diameter/2)^2

Milliliter/CC over exaustport:
=CC*((100-(Dexaust/306*100))/100)/(Wanted Dynamic compression-1)
or
= 1*(PI/4)*(Diameter^2)*(Ee-C)/1000

And loads of other.


So any1 know a good way of making me get how many mm heigh? i need to have left and still be able to make the correct form and correct volume inside?

I was thikning:
1. Finding volume of dome for piston. (46,95mm wide, 0mm height outer edge, 2mm height center.)
2. Finding volume for squishband (47mm wide, 0,4mm height outer edge, 0,7mm heigh outer edge)
3. Finding volume combustion dome (30,38mm wide, xxmm height center, curved like on picture below)
4. Finding volume of the upper center of piston(from 30,38mm wide and up, the part of squish that is inside combustion chamber volume)

Volume squishband dome + volume combustion dome - volume piston dome - volume of upper center piston.
Then just put correct squishband outer and inner height(mm).
Then put correct dome height of combustion(mm) <- Change this until i get correct volume.