Quote:
	
	
		
			
				
					Originally Posted by  kerry
					 
				 
				I am stlll puzzled by the claim that vacuum parks the piston forward. 
			
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 The physics to support the claim are just not there.  Given the small area of the piston, there is no way that atmospheric pressure is going to offset the force of the return spring.  And from an engineering standpoint, 
not having the roller in constant contact with the cam would be highly undesirable.