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gvr4 · 01-05-2013

NO!

More important than the location of the valve reliefs is the 1mm offset on the wrist pin. That is meant to reduce piston slap and reduce the forces seen by the crank as it passes TDC. If there wasn't an offset, the cylinder would fire at exactly TDC, when wrist pin, crank pin, and main centerlines were all lined up, and for an instant, all the combustion force would be transmitted directly onto the mains. If the offset is backwards, piston TDC is achieved slightly before the crank reaches the highest point in its rotation, so when the piston fires, it's almost like trying to rotate the crank backwards for an instant.

01-05-2013	#2
gvr4 New Member Join Date: Sep 2012 Location: North Branch Drives: I walk. Too many broke vehicles Posts: 40	Re: Piston to valve Clearance? NO! More important than the location of the valve reliefs is the 1mm offset on the wrist pin. That is meant to reduce piston slap and reduce the forces seen by the crank as it passes TDC. If there wasn't an offset, the cylinder would fire at exactly TDC, when wrist pin, crank pin, and main centerlines were all lined up, and for an instant, all the combustion force would be transmitted directly onto the mains. If the offset is backwards, piston TDC is achieved slightly before the crank reaches the highest point in its rotation, so when the piston fires, it's almost like trying to rotate the crank backwards for an instant.