1983 380 SL valve guide?

[deportes]

I keep coming up with questions about this job. I am hoping to avoid the removal of the driver side head in order to inspect the valve guide seal and guide for that matter. While trying to remove the spring using a top side spring compressor tool, I compress the spring enough to be able to move the valve down into the cylinder approx 1/2 inch, while not being able to loosen and remove the keepers I notice that when I push down on the valve the cylinder press does not drop. Is 1/2 inch downward movement on the valve not enought o release the 180 psi I have pushing up on the valves. I am nervous about continuing the effort to remove the keeper when I am not sure how the pressure is not being released into the intake manifold when I push down on the valve. From my past days of rebuilding engines I remember the valve seat was not deep, Am I missing something? At the same time when I depress the valve on the pressure gauge contraption being used to pressure up the cylinder and left in place attached to the compressor in case the press should start dropping, it releases the press and you hear the discharge. What am I doing wrong? other than not taking the car to a pro.