the specs should be right there in the Bentley book.
I just went through this on a  couple of diesel engines..
the spec for ring land clearance is there,
for ring end gap in the cylinder,
or for piston fit in the cylinder.

in general, once the rings are disturbed, they should be replaced, on VW
engines, in my experience.
----- Original Message -----
From: "John Rodgers" <inua@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, May 27, 2011 1:04 PM
Subject: Re: Rings are stuck ...

>  As said, a small screw driver applied to the ring gap should pop them
> out. But, rings are not reuseable. More importantly, if the cylinders
> overheated, it is likely that the ring lands in the pistons are damaged
> beyond use as well. After the pistons are cleaned thoroughly, with a
> feeler gauge you can measure ring to land clearance by putting a proper
> ring in each land and measure the clearance with a feeler gauge.
> Hopefully you can find the specs for this somewhere. Also, you should
> check the cylinder barrels with a dial indicator for out of round.
> Scoring can be felt with you nails, but a dial indicator will give
> better results. Numbers don't lie. If you get much variation at all,
> it's time for new pistons and jugs. That's just the way it is sometimes.
>
> John
>
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, AL
> Http://www.moldhaus.com
>
>
> On 5/26/2011 9:03 PM, HotelWestfalia wrote:
>> Hi to all,
>> I have the four pistons out and would like to free the rings from all the
>> four of them out.  They are all cooked in solid from overheating.  I
>> don't know a sure way of getting them free again.  Would it be some kind
>> of boiling them in something for a few hours?
>> Anyone knows this?
>> Best wishes,
>> Zoltan
>>
>>