Sparkem, I think there are two different problems here. One may be that worn lash adjusters (LA) won't hold pressure and so 20W-50 reduces the leakage. The other is that the LA's drain down overnight and take a little time for the oil to pressurize them. My problem seems to have been the latter so using a 0W grade allows the oil pressure to build faster on startup. I don't like using 20W-50 on street vehicles as I think it takes far too long to circulate on a cold engine and I think it is overkill.

92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles