It never stops tapping loudly!  I have one that takes 20 to 30 minutes, sometimes more, at 50-60 mph to stop tapping, it eventually does.  It's best to run it at high rpm right away because it's a bit easier on the cam. The lifter "floats" a bit and doesn't hit the cam lobe so hard.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John Rodgers
Sent: Friday, March 06, 2015 5:02 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Valve lifter

How would one positively identitfy a lifter that refuses to pump up?

I have a bad one and need to replace it.

John