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Old 08-31-2019, 04:32 PM   #8
Royce P
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Join Date: May 2010
Location: Tulsa OK
Posts: 473
Default Re: High compression head question

The math is quite simple. You need the volume of the combustion chamber with the piston at TDC. You need the volume of the combustion chamber + the cylinder's swept area with the piston at BDC. Add the two. Then divide the larger sum by the other.

Variables include type of piston and the bore size. Several capable folks have measured the cylinder head and done the math with results in the neighborhood of 6:1 ratio. If Mr. Prus says otherwise ask him to provide the math that he is using to come up with a different answer.

I personally have never seen one but hear nothing but good reviews of the product. If you think a high compression head is what you need then why not just buy one and try it?

Originally Posted by AzBob View Post
I would like to see the data that proves the Prus head does not deliver the advertised 8:1 compression. I was assured by Mr. Prus himself that it indeed delivers 8:1.
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