okay, i've had to break my code of silence and post....

a bit of experience to share with the tire issue, i've run 15" tires on
my '78 bus without difficulty or speeding ticket, so outside of the 
absolutely fascinating mathmatical possibilities available in this 
situation, the rubber will roll, and turn.

as for the excessive oil usage, i'm in the same boat.  last september
i started getting excessive oil drippage which turned out to be the 
case bolt which acts as the support for the oil drain assembly. 
there is a bolt which in my model (2000cc) holds the pan on and
also the screen etc in the bottom of the case.  this assembly 
has a bracket which the case bolt went thru and somehow thru time
and probably overtightening of the oil drain bolt, the case bolt
caused the case to crack where it screwed in.  a rare case of 
bad design, i'd say.  the case bolt was screwed into a tapped
hole which was merely an aluminum blob cast on the case and it
makes sense that it wouldn't put up with much torque in any 
direction besides in/out.

i will also say that there is a lesson about overtightening the 
oil drain bolt in this engine model or others like it. so the saga
continues...

after two engine outs, we decided to rebuild the engine with a new
case, reworked heads, bearings etc, but no new cylinders or pistons.
we did put new rings in.  since then i have found that the engine
is using almost exactly what you describe as a quart per 200 miles.
my guess in my case is that i need new cylinders and pistons since
there is no apparent drip and everything else is new.  it runs fine
altho maybe a bit shy on power up hills.

there is also no big blue cloud out the back. i am also partly 
mystified and would like to hear from others who know of such 
things.  i did hear that a good way to test compression and 
the cause of loss of such is to do the following...

a.  test the compression 
b.  squirt some (2-3 Tbsp) oil into plug hole
c.  test the compression

apparently if your compression increases greatly, its your rings, since
the extra oil will compensate for any wear.  if not then you have head
problems since the oil will not assist in that area.

as the sign says...

Tips are greatly appreciated.

Andy 

conkaj@aur.alcatel.com

'74 beetle (pepito)
'78 bus (katanka)
'71 westie (nameless until a suitable adventure)