Oh... now I get it... I think it's time for another egg nog.
Merry Christmas everyone.
Mark Bullard
----- Original Message -----
> Bob:
>
> Well, lets see:
>
> Remember that I have a 1974 motor with a stock compression ratio
of
> 7.75:1, so I need to go a looooong ways to get to 9.5:1.
>
> The milling of the head took the combustion chamber volume to
44.5cc
> (I cc'ed the head to determine how much to remove). The TR6 gasket space
is
> 4.5cc according to David Vizard in "The Theory and Practice of Cylinder
Head
> Modification", so I end up at 49cc for the combustion chamber volume
(CCV).
>
> The stroke is 3.74", and with the 0.020" overbore the bore is
2.96".
> So one cylinder displaces -
>
> Pi x R^2 x STROKE
> or
> 3.1415 x 1.48^2 x 3.74 = 25.7 cu in, or 421.22 cm^3 (DISP)
>
> The compression ratio is defined as:
> CR = (DISP + CCV) / CCV
> or
> CR - 1 = DISP/CCV, so
>
> CR - 1 = 421/49 = 8.60
> and
> CR = 1 + 8.60, or
>
> CR = 9.60:1
>
> Close enough.
>
> Vance
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