Thread: compression
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Old 01-12-2009, 01:05 AM
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Gaz64 Gaz64 is offline
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Lads, overlap has nothing to do with compression pressure while cranking.

The valve event that influences cranking pressure is inlet valve closing point.

After all, compression can't start until the inlet valve is shut.

So if the closing point was example 90 ABDC, the piston would be halfway up the bore on the compression stroke and no pressure will build at 300 rpm (cranking) until the inlet is shut.

Static compression ratio could be 12:1, dynamic would be 6:1.
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Last edited by Gaz64; 01-12-2009 at 02:01 AM..
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