Could be a broken spring/check valve, but I'd give it an hour of driving before you replace it. I've always been reluctant to put a new lifter on an old cam, but maybe it would be okay, especially if you coat the lifter with a  good quality cam break-in grease.

Stuart

-----Original Message-----
From: John Rodgers [mailto:jrodgers113@gmail.com] 
Sent: Sunday, March 08, 2015 2:18 PM
To: Stuart MacMillan; vanagon@GERRY.VANAGON.COM
Subject: Re: Valve lifter

I've tried the speed run over time and distance. Just doesn't pump up. 
Loud as ever!

John

On 3/8/2015 4:07 PM, Stuart MacMillan wrote:
> 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
>