It's the heat that expands the steel parts.
The various parts just expand and consume that .006.
Various parts = Lifters, Rocker Arms, Valve Stems, Pushrods, valve seats.
Check out .006 on a feeler gauge, it's about 1/2 as thick as typing paper.

Stan Wilder

----- Original Message -----
From: "Daniel L. Katz" <katzd54@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, June 27, 2004 9:45 PM
Subject: Re: Hydro lifters (# of turn)

> list:
>
> interesting. but does the .006 disappear because the hydraulic lifter
> pumps up, or because a film of oil is created, or what?
>
> surely the .006 in the solid lifter case could not disappear becuase of
> heat alone - the gap itself would be expected to increase roughly in
> proportion to the overall thermal expansion of the engine as it warms up.
>
> dan
>
> On Fri, 25 Jun 2004 13:55:46 -0500, Stan Wilder <wilden1-1@SBCGLOBAL.NET>
> wrote:
>
> >That .006 just disappears when the engine gets warm. The lifters will run
> >very quiet other than the occasional clatter when you start in the
> mornings.
> >I run .006 on the intakes of solid lifters on my Porsche and the .006
> >tightens right up to be total silent with just a little heat.
> >
> >Stan Wilder
> >