Volvo D6E IEGR System

I have a noisy tappet that needs attention.
I have already made one adjustment but it didn’t fix the issue, I didn’t crank down the valve enough it appears.
My question is can I run the engine without the IEGR system bolted on.
the procedure to adjust valve lash on this engine requires the IEGR system, which is a big chunk of steel bolted on top of the valve assembly, to be removed, valves adjusted then IEGR system bolted back on and the Plungers in the system adjusted much like the valves. I want to try doing the valves only to see if I can get the tappity-tap-tap sound to go away before putting the IEGR back on to save myself the hassle if I have to make another adjustment. I was thinking of disconnecting the solenoid which activates the oil pressure which drives the IEGR system.

I’ve attached the procedure, scroll to page 25 to start
hope this makes sense.

thanks