Yeah JDMClifford, I didnt think about the fact that in pulling your cams, you have to bleed the lifters, because if the cam was pressing down on one (which it is, no matter what position it was in when you pulled it) and you relieve that pressure, air gets sucked in... anyway, you can check for compression first if you want, just hook up a compression gauge and turn the engine over by hand and see if you're remotely close (if there's a problem with lifters/compression, your readings will be somewhere around 20-50, instead of >120). Here's some info from jgycustoms.com:
Does your SR20 have a "TAP-A-TAP-A-TAP-A-TAP" noise? The most likely suspect is air in the lifters. If you look at my finger location in the picture, I'm pushing down on the back of the rocker arm on the section that rides above the lifter. While pressing, if you feel any movement, you have air in that specific lifter. SR20 lifters are hydraulic but can not bleed themselves like most hydraulic lifters. To bleed your lifters you must remove your valve cover, the cams, and rocker arms. Pull the lifter out of its sleeve making note not to tilt it sideways, submerse it in oil, and insert a thin piece of rigid metal inside the hole on top of the lifter. Keep in mind, entire lifter must be completely submersed in oil. You will feel a groove with your metal probe, if you press down it will compress the internal mechanism. Do this repeatedly, many times, or until it doesn't depress anymore. Carefully insert it back into the sleeve without tipping it so that air does not enter it. Reinstall the rocker arms, cams, and valve cover and listen to see if the noise persists.