exactly what Tom says here.
It sure 'should be' what we're calling a square ( I'd call it flat ) seal,
and uses a sealing washer ..
that you just leave on the spark plug, where it should automatically be.

driver's side rear is # 4 in any opposed four VW engine.

as long as the insert doesn't come out with the spark plug, it should be
fine.
If there is a compression leak at the sealing surface where the plug screws
into the head and insert...
you should hear the leak with the engine running - listen there with a
listening tube held to the ear.

Scott
www.turbovans.com
----- Original Message -----
From: "Tom Hargrave" <thargrav@HIWAAY.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, May 03, 2010 6:02 AM
Subject: Re: Found a timesert in the spark plug hole

> Mark,
>
> 2 spark plug seal designs exist.
>
> The square seal is the one with the crush washer you have to make sure is
> on
> the plug before you install it.
>
> The taper seal has no crush washer. Instead the sealing surface on the
> plug
> and the head are tapered like a flare fitting.
>
> All the VWs I've owned had the square seal but I've not owned anything
> with
> the wasserbus engine yet.
>
> Tom
> www.stir-plate.com
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
> Mark Dearing
> Sent: Monday, May 03, 2010 7:16 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Found a timesert in the spark plug hole
>
> In a message dated 5/2/2010 2:36:04 P.M. Eastern Daylight Time,
> syncronicity1@GMAIL.COM writes:
>
> So a  question, does the Vanagon spark plug hole have a tapered or square
> seal at  the top?  Could this old "timesert" thing be the source of  low
> compression if it was incorrect?  A couple of compression tests  several
> months ago showed this cylinder low (can't recall the number, the  rear
> one
> on the driver's side).
>
>
>
> hello Roland there are a bunch of different plug inserts out there. They
> all
> work about the same.  no compresion loss if installed correctly and  head
> has no cracks.  hole is not tappered and I don't know what you are
> calling
> a square seal? Plugs do have sealing rings on them and should be left on
> later  mark d