On Aug 6, 4:59*pm, "Anyolmouse" wrote:

Serious question- Why do you have to see how much the marbles displace?
If you use the same marbles every time it shouldn't matter. I.E., the
two marbles + 35cc is two marbles +35cc in all cylinder heads.
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Dear Anyolmouse,

To determine our compression ratio we need to know the NUMERIC volume
of the combustion chamber. Using marbles (or whatever) to take up
some of the volume, reduces the procedure to one vey careful discharge
of the syringe. I've a hunch this question would have answered itself
if you had cc'd a head, when you find yourself wishing for an extra
hand or two :-)

Compression Ratio is normally defined as V1+V2+V3 (divided by) V1+V2
(where V1=the swept volume of the cylinder, V2=the volume of the deck-
space, and V3=the volume of the combustion chamber). I think I've
included this procedure in my blog.

-R.S.Hoover