I was wondering if there is any difference in the v-tec syleniods of a B18C1, C5, or B16?

 

alllllll the same!

and by the way, its spelled "solenoid"

so·le·noid A Pronunciation Key (sl-noid)
n.
1. An assembly used as a switch, consisting of a coil and a metal core free to slide along the coil axis under the influence of the magnetic field.