Date:         Fri, 12 Dec 2003 13:52:07 -0600
Reply-To:     John Rodgers <jh_rodgers@BELLSOUTH.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Rodgers <jh_rodgers@BELLSOUTH.NET>
Subject:      Cylinder Types
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I just visited the Raby Aircooled web site. Raised some questions in my
mind. Curious about what cylinder types are available for the WBX
engines. Cylinder material, matching piston materials, ring materials.
Back in my aviation days I remember aircraft cylinder barrels being
steel(or maybe cast iron - machined, but don't think so) with steel fins.

Aircraft engines short blocks were much like that of the WBX and the VW
Aircooleds. Split case, crank, cam, rods and pistons.  There the
resemblance stopped. Aircraft cylinders were - operationally speaking -
one piece including the cylinder head. The head was an assembly made up
of a machined aluminum casting, with valve seats, valves guides, etc.
pressed in. The head was threaded to accept a threaded steel cylinder
barrel. The dissimilar metals were dissimilarly heated, then threaded
together. Once cooled to the same temperature they would not separate. A
crack might occur at the thread line - that I have seen - but basically
the two components would never separate. Each cylinder was then attached
to the case by short studs that suck out from the surface of the case.
This cylkinder barrel assembly was a complete unit. No heads to mess
with, no head gasket leaks, etc, etc, etc. The steel cylinder barrels
interior surface was "Nitride" treated for hardness, or alternately,
chrome plated and then machined again. The chrome would have tiny little
crevices thoughout the surface that trapped oil and provided for
lubrication. Because the chrome was so hard, gray iron rigns were used
in the chrome barrels to allow the rings to wear in to the cylinders
rather than the other way around. Sad the day when someone put in rings
other than the gray iron into a chrome cylinder.

Anyway, I have wondered why no one ever came out with a combination
head/cylinder barrel for the VW. Would have eliminated a ot of
headaches. What type barrels are available out there today????

Regards,

John Rodgers
88 GL Driver