Okay...I think I sus'd it.
Remove the plunger.
Install small spring in plunger.
Install check ball next.
Install check valve with 'o' ring side facing down.
Install plunger into tensioner body from cap end until against retainer.
Install large spring with spacer rod into body making sure spring sits on check valve square.
Compress large spring with cap and screw tight not forgetting alloy washer.
Fit to engine, not forgetting alloy washer.
Job done !
NOTE. The tensioner recieves pressurized oil at the engine/tensioner interface. Oil enters tensioner main body and exits at a predetermined pressure past the ball check valve to exit the tensioner from the hole in the end of the plunger causing the plunger to be pressurized and push against chain tensioner blade.
Vented oil drips into chain case. The large spring is to set tension when oil pressure is low or engine stopped. Small spring sets main chamber oil pressure.
Hmmmmm, neat !