The tension of the spring isn't terribly important- - - -it's just a "fail safe" in case pressure might go very high with cold, thick oil on a winter startup. Free travel of the relief plunger ahead of the spring is vitally important- - - - - -if it sticks in even a slightly open position, either from burrs on the piston or a tight fit in the bore, the oil pressure will drop dramatically. Be absolutely sure the relief plunger travels freely.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!