You cant "adjust" them like you normaly would on most other motors, You have to reshim the lifter bucket.

Get a chilton or FSM for any car with a Dohc KA and it will show you how to shim the valvetrain. After you take all the specific mesurements, go to Nissan and buy the shims according to what thickness you need.

PS it sucks, and you will have to take the cams out to insert the shims. Lable the shims so they go back in their correct spot.

G/L