http://users.telenet.be/jannemie/FOS%20 ... black.xlsm

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

**ORIGINAL FIRST POST :**

Mj's program to calculate cylinder heads, can be downloaded here :

myweb.tiscali.co.uk/teamsparrow/cylinderheadsv2_3.xls

now I've been playing a bit with it, but have some questions :

on the "Hemi head" page :

- what is the "volume layer" ? I can't figure out what it corresponds to on the figure. Is it the volume of the entire squish-layer ?

- if it is so, then the "volume squish" is the volume under the squish only in the squish-layer, without the volume under the dome in the squish layer ?

- "squish area ratio" : as I reed it, it's the % of the squish-surface from the total bore-area ?

- what is the "bowl" in "height of dome in bowl" ? in the formula, there is a reference to "C33" but there is no "C33"-line ? is the dome = the head radius ?

- what should we learn from the graph ? do we have to maximalise the squish-velocity ? or do we want the area under the squish, but above the piston to be as big as possible ? what's the relationship with the piston-velocity ?

- the table below the graph : what are "Vol squish", "Asq" , "Y" and "Z" ?

and a more general question : do hemi heads have an advantage over conical heads ? 'cause conical's are much easier to produce on a lath