Here is a modification of Bulley's method in case you really want high
accuracy:

Take all the plugs out, it is much easier to turn the engine by hand.

Instead of using a finger, take an old spark plug and break the center
and side electrode off, clean it up with solvent, then epoxy a 1 1/2" x
1/4" bolt into the hole (head first) you have created and wait for it to
cure fully.

Just to be absolutely safe, disconnect the battery.  Then insert the
modified plug half way (to minimize compression that will make the
engine harder to turn), making sure the #1 piston is down.  Hand rotate,
don't use any tools, VERY SLOWLY AND CAREFULLY until the piston touches
the new tool you have just made, mark the pulley at the case parting
line, then rotate the other way and do the same.  Measure the exact
center between the two marks and you have it within a half a degree.
You can attach a degree plate to the pulley now if you like for things
like cam timing, etc.

Have fun, and don't forget to remove the "tool"!

Bulley wrote:
>
> That's not really the most accurate way. Although we don't now if you are
> talking about an air-cooled or water-cooled van, you can find EXACT TDC the
> following way.
>
> Assuming you are looking for #1 TDC, remove the #1 spark plug, and the
> distributor cap. Roll the engine over by hand (using a wrench) until the
> dist. rotor points 'roughly' at the #1 quadrant of the distributor (where
> TDC should be).
>
> Wet your right pinkie finger, and loosely jab it into the spark plug hole.
> Roll the motor over in the proper direction (clockwise) with the wrench.
> You will feel either pressure or suction, depending on whether the piston
> is BTDC or ATDC. Roll the motor back and forth until you find the mid-point
> between BTDC (pressure) and ATDC (suction). Once you find the midpoint
> (your finger is still in the hole) curl your pinkie finger and attempt to
> touch the piston crown.
>
> On Type 1's, older 911's, 356's and type 4's you can feel the crown at TDC.
> I've never tried on a wasserboxer, but I'd bet you can, if I were a betting
> man. Move the motor slightly to confirm the piston is ALL THE WAY to the
> top. Mark the pulley.
>
> If you have fat fingers, find someone with thin pinkies.
>
> G. Matthew Bulley
> Bulley-Hewlett
> Corporate Communications Counselors
> www.bulley-hewlett.com
> Cary, NC USA
> 888.468.4880 tollfree
>
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--
Stuart MacMillan
Manager, Case Program
800-909-8244 ext 208

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