Again we need to set the record straight on
terminology. The diameter of the clutch (180mm or
200mm) does NOT go hand-in-hand with the tooth-count
of the flywheel (109 for 6V, 130 for 12V).
As a rule, VW used 180mm clutches on 1200 and 1300cc
engines and 200mm clutches on 1500 and 1600cc engines.
Yes, the 180mm flywheel is a slight detriment to
"revability" compared to the 200mm setup because it
contains more mass near the perimeter - a bit more
than is offset by that of the larger 200mm clutch. But
it's a minor point, trivial compared to the inherent
deficiency of the small clutch when it comes to
handling significant horsepower...a "heavy-duty" or
"Porsche" 180mm cover is needed IMO for anything
bigger than a stock 1300, and the pedal pressure and
wear & tear on the clutch cable and related components
is undesirable - a stock 200mm clutch holds better
with less effort....and the weight of the stock 200mm
flywheel/clutch setup is still plenty adequate for
your bus (it's what the factory used on all `67 buses,
after all).

There were 1500cc engines back in the 6V days (found
in buses and Type IIIs), and VW continued to produce
1200 and 1300cc engines for other markets after the
switch to 12V occurred. Therefore there are six
different stock flywheels:
6V (109-tooth) non-O-ring 180mm clutch (Most common 6V
Type I, used on `61-early`66 bugs and 1200cc buses)
6V (109-tooth) non-O-ring 200mm clutch (1500cc buses
and Type IIIs)
6V (109-tooth) O-ring 180mm clutch (late`66 bug)
6V (109-tooth) O-ring 200mm clutch (late `66 bus/III)
12V (130-tooth) O-ring 180mm clutch (12V 1200/1300cc
engines, never offered in US market)
12V (130-tooth) O-ring 200mm clutch, the most common,
used on every Type I/III sold in the US from `67 on
and on `67-`71 buses...it was also used on some
late`66 'Ghias that still had a 6V electrical system
along with a special starter, rare as hen's teeth in
the US (SR14) - THAT was an effective old-school
hot-rodder combo, running that 6V starter on 12V gave
extra oomph for cranking a high-compression engine
(read on)
109-tooth `wheels do not have induction-hardened teeth
like the 130-tooth ones (look at the tooth area of a
12V `wheel, you'll see it has a blue discoloration
caused by that process) and will rapidly wear out when
you run them and a common SR11 6V starter on 12V. The
starter itself will hold up just fine, provided it's
never overheated by extended cranking, but the
flywheel teeth are another story. Fitting a 12V
solenoid will ease the initial engagement clash and
lengthen the flywheel life considerably, but it'll
still never hold up the way a 130-tooth will...unless
you mill the teeth completely off and shrink on a
hardened replacement ring gear as was done on
factory-exchange engines (you can buy those ring gears
from Gene Berg still I believe, but they're spendy -
as is the machinework).

Now, to the question of fitting a non-O-ring flywheel
to an O-ring crank.
Yes, it will fit. Obviously you must use a gasket
between them, and remember what I said earlier about
the perils of using early endplay shims on a late
crank - be sure to use only the smaller-ID shims
intended for use on the O-ring crank, if they'll slip
past the step onto the main-bearing journal area
they're the large-ID non-O-ring style.

I wouldn't plan on using a non-O-ring 6V 200mm (forget
about a 180mm altogether for a bus!) flywheel on your
future O-ring-crank 1600 just to save the cost of
buying two starters for two reasons. One, the
aforementioned weakness of the non-hardened teeth on
the 6V 'wheel, and Two, the O-ring setup is much more
reliable when it comes to keeping oil off the clutch -
there was a good reason for VW to bother to change the
design.

Now, if you happened to find a factory-exchange O-ring
109-tooth 200mm flywheel that had the hardened-steel
replacement ring gear, you could run THAT on the 1600
with a 6V starter on 12V for a long long time...good
luck finding one ;)

--- Dan <[EMAIL PROTECTED]> wrote:

> This is kind of a weird situation because I'll only
> be running the 1500cc 
> engine (6v crank) for at a few months until I get my
> new engine (12v crank) 
> built.  If possible I am trying to bet by with only
> purchasing one starter. 
> Someone Emailed me saying: "...and by the way: the
> 6V 200 mm clutch flywheel 
> on this vintage bus are an old hot rod item.  They
> are much lighter in 
> weight than a Type I 6V flywheel so you get the
> benefit of a lightened 
> flywheel if you use a 6V bus flywheel in an early 6V
> bug."  Can anyone 
> confirm this?  My bus is being built as a highway
> cruiser and camper not a 
> dragster so a lightened flywheel is not something I
> want.  I always thought 
> the hot rodders wanted the 200mm flywheels for the
> bigger clutch disc.
> 
> -Dan
> 
> 
> 
> ----- Original Message ----- 
> From: "No Quarter" <[EMAIL PROTECTED]>
> To: "Air-Cooled Volkswagen Discussion List"
> <[email protected]>
> Sent: Friday, January 25, 2008 6:27 PM
> Subject: Re: [vintagvw] 12v flywheel on 6v crank
> question - Part two
> 
> 
> > Your idea of the 6V starter isn't a bad one Dan. 
> 6v starters last forever
> > and with 12v they *really* get the engine
> cranking.
> >
> > And I guess I sort of answered your question you
> posted in the subsequent
> > post.  That 1966 beetle I worked on used a 6v
> flywheel that had been 
> > turned
> > down or something to fit on the 12v engine.  If
> Marc can't help you here,
> > you might want to give Phil a call at
> 1-800-805-7098 and ask him.  Then 
> > you
> > might see if he has a starter for you.  At least
> appease him for his info
> > and buy something from him.  I usually buy oil
> change kits or something 
> > like
> > that. :)
> >
> > Erin
> >
> > _______________________________________________
> > vintagvw site list
> > [email protected]
> > http://lists.sjsu.edu/mailman/listinfo/vintagvw
> >
> >
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> > 1/24/2008 8:32 PM
> >
> > 
> 
> _______________________________________________
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