Have a look at this thread and it may give you more info.
http://forum.s15oc.com/showthread.php?2286-VTC-Solenoid-question
http://forum.s15oc.com/showthread.php?2286-VTC-Solenoid-question
Strange rattling sound when first pulling away?
typical, just read the thread on nissansilvia.com
http://www.nissansilvia.com/forums/index.php?showtopic=226138
works out cheaper to get adjustable cam gears then get a replacement solenoid from nissan
like the NZ made ones works out to $200NZD nissan was approx $500NZD for replacement.
http://www.drivenperformance.co.nz/scripts/prodView.asp?idproduct=1612
http://www.nissansilvia.com/forums/index.php?showtopic=226138
works out cheaper to get adjustable cam gears then get a replacement solenoid from nissan
like the NZ made ones works out to $200NZD nissan was approx $500NZD for replacement.
http://www.drivenperformance.co.nz/scripts/prodView.asp?idproduct=1612