[6pack] Compression Ratio Calculation

[Robert Lang]

On Mon, 7 Jan 2008, Navarrette, Vance wrote:

> 	The 0.080" number that Roger Williams mentions is based on a
> starting compression ratio of 8.5:1 (?).

That is correct.

If you look in the Kastner TR6 Competition Prep Book (aka the Bible), it 
tells you this very number - later heads must take off and additional .080 
to get the the numbers. He uses 10:1 and 10.3:1 (stock block and decked) 
and 12:1 / 12.3:1 (stock block and decked) as his target compression 
figures.

But in every case, to know the exact combustion chamber volume, you need 
to do what Vance did - set up the burrette and measure.

Interestingly, TR6 cylinder heads have very good tolerances, so the "mill 
this amount" method does work, even if it's not "exact".

And the chart on Goodparts is a great guide.

> 	Vance

regards,
rml
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