So in my PNW hippy way, it seems that you could both
be right, just at different points in the pistons
travel.

One has to see that the conrod angle pushes the piston
down on the power stroke and up on the return stroke.
The effect of this "non-axial" force is greatest at
90* from TDC, right?  Which just happens to occur
lower in the piston...  Increased force... bigger
taper lower down...  Personally, i see a connection.

However, this doesn't really account for the effects
right near TDC, where i am sure gravity plays a more
significant role (although you don't need a very big
vector to eclipse a 1lb force pushing down - about
3.4"^2 piston area.  Even a mere 150psi compression
test is 513.5lbs of force on the piston... inverse
tangent of that, we get a whopping .002 degrees of
offset conrod angle to exceed that 1lb slug).  Two
hundredths of a degree to equal one pound of force
pushing down really isn't all that much!

Of course, any conrod offset will simply help the
pro-gravity camp, but i feel pretty confident now that
piston forces make the lions share of wear on the
cylinder walls...

All i can say in conclusion, though, is peace and love
man... peace and love.

Better living through science,
-Damon

p.s. i've only ever built one engine, and have never
measured bore, taper, or anything like that, so take
the above commentary for what it is... armchair
mechanics.  Except my chair doesn't have arms...

--- John Connolly <john@AIRCOOLED.NET> wrote:

> But all of this beats around the fact that gravity
> IS an issue, and is a
> prime contributor to the ovaling of VW cylinders in
> the Flat-4 engine. If it
> wasn't an issue, then the cylinders would be round
> because of the offset
> wrist pin, RIGHT? ;-) But I've found they are not
> round, they oval out, with
> the larger dimensions top/bottom instead of
> side/side.
>
> I will concede that I have not measured the
> cylinders on wasser engines,

=====
'84 Westy (Sparky) w/2.3L WBX (wow... it actually works!)

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