this wont be neat coz i cant be arsed and as JEEVES states i dont know my space key from his hardarse but i hope its some help,we used to build race engines for rally cars and work it out like this...it all hinges around compression...though make sure on your piston extrusion too,you dont want to bolt up and find a 1mm gap coz you added something up wrong,if the piston emerges from the top of the block remember that and measure it for adding on at the end of this....ok....depends on wheather you want to play safe or get every last drop of compression out of your engine,which also depends on boost pressures and quality of fuel-too thin and you will detonate or risc valve/piston touching....work out the compression ratio you want to run at or is suggested best for the engine,you also need to know the cylinder displacement and odd volumes in like the valve cutouts,piston to deck clearance and the head gasket you wish to use..this gives you a total chamber volume..now take them away from the total volume you actualy require which leaves you with the volume the chamber must contain to give you the ratio....no easy but worth the hastle in the end...so the total chamber vol =cylinder disp divided by comp ratio...
oh look found a shift key...
on the 1600 stuff we used to do alot of it was like this...ummm an 11;1 ratio is wanted on a 1600 engine say so total chamber vol is 1600cc divided by 4 over 11;1 which equals 400 over 10 which = 40cc
say for instance 12cc of this vol is contained in piston/deck vol,valve cutouts..and so on..the ratio you want has to be 40-12=28cc sooo the head must be macined until it contains 28cc in its chamber to produce 11;1...
put the head dead level,you could use a spirit level and shims if you want if you havnt got an eng table,and make sure the plugs and valves are in.use a pipette or burette and fill the largest chamber with fluid of the vol you require,then place a straight edge over the chamber and measure down to the fluid from the edge with a vernier or simillar..the figure you now have is the amount to be machined...simple eh...hmmm....you still with me jeeves?
in reality mind something called molecular attraction comes into force and attracts the fluid up to your vernier somewhere around the 0.15mm mark but its ok coz this gives a nice safety net unless you are big time comp where it all matters.
so basically its easier to work before its machined but is ok if not....get the spec on the different gaskets,work ot their vol then work the rest on top..there are other probs with valve/piston contact but i dont think you will be running cam profiles that wild on a big fat lazy revving engine like the supra has...
or-you could just buy a thin gasket and take your chance,or a big fat one and say who cares.
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