<VV> Valve lifter noise

[Hugo Miller]

I just dragged one of my Corvairs out of hibernation, & there was a 
loud clatter from one of the valve lifters on starting, which persisted 
for several minutes before gradually fading away. I assumed it was just 
that the oil had drained out of one of the lifters due to standing for a 
long time. But the next day the noise was back. Again it faded after a 
while. I've only been running it for about three days now, but if this 
is going to happen every day I shall need to do something about it. Has 
anybody else experienced this phenomenon?