Hi, listers;
I was doing some basic calculations on the displacement of my GT6+ engine and
came across something curious.
Using the stock bore: 7.47cm (74.7mm) and the stroke: 7.6cm (76mm) I
calculate a displacement of 332.9cc per cylinder and multiplying that times 6
cylinders gives a total displacement of 1997.45cc- just slightly under the
published displacement of 1998cc. It is obvious to me that the factory didn't
take into account the volume of the combustion chambers in calculating
displacement. Is this common practice?Do most manufacturers publish swept
volume as a measure of displacement?
A GT6+ combustion chamber in a 10.75CR head has a volume of 30cc according to
the Competition Preparation Manual......so......a 9.5CR head should be
approximately 26.5cc plus 4cc for the head gasket. Multiplied times 6 this
would be 183cc which added to 1997.45 gives 2180cc.
The reason for this exercise is that I am trying to calculate the proper
combustion chamber volume for a 10.75 head if the bock is machined for .040
oversized pistons. Speaking of which, does anyone have any experience in
using the .040 oversized pistons.....any block problems, like weak cylinder
walls, etc.
Still trying to decide between a 1998cc engine and the 2498cc from a TR6.
Some listers comments about high revving GT6 engine made me do some more
thinking. In my mind it is still an issue of reliability, not necessarily
maximum horsepower.
Any comments or opinion will be appreciated.
Greg Wolf
1970 GT6+ "Ian"
Ann Arbor, Michigan
Winnipeg MB Canada
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