and a progressively lower valve lift second there is no apparent method for conveniently setting internal mechanical lash during assembly of svl 10 as shown in the 39 175 patent third the axial positions of upper end 35 of slot 32 and locking port 38 define the amount of internal mechanical lash and are subject to variation in manufacturing tolerances of pin housing 24 plug 30 and body 18 making the amount of lash in any given unit and hence the precise point of opening and lift of an associated valve unreliable referring to fig2 a second prior art single pin svl 10 u2032 is shown substantially as disclosed in u s pat no 6 606 972 b2 u201c the 39 972 patent u201d it is seen that the basic construction is very similar to that of first prior art svl 10 except that return spring 25 u2032 is disposed below pin housing 24 u2032 rather than surrounding it while a means has been provided in svl 10 u2032 for setting mechanical lash svl 10 u2032 has the other shortcomings as svl 10 recited above especially since it utilizes a cylindrical locking pin 36 u2032 having a circular cross section that locks into a round locking port 38 u2032 formed in bore 20 u2032 of body 18 u2032 as noted above this shortcomings would also exist if the locking arrangement were used in a single pin shla as an improvement over a single locking pin.