Date:         Sun, 17 Nov 2002 14:33:51 -0800
Reply-To:     Mark Keller <kelphoto@HIGHSPEEDPLUS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Mark Keller <kelphoto@HIGHSPEEDPLUS.COM>
Subject:      Timing adjustment procedure on Digifant system
Comments: To: danoer1@ECLIPSE.NET
Content-Type: text/plain; charset=us-ascii; format=flowed

Hi Dan,

I've long suspected that many waterboxer "low power" complaints have
iginition timing that is in tolerance but less than optimum value.
 Below is a procedure to set an optimum timing value. If you can, search
the archives under my name, available through Vanagon.com's website,
I've posted many articles on tuning the waterboxer's fuel injection
system as well. You must verify that correct timing and fuel pressure
are present since these two things are assumed by the computer  when
setting it's basic fuel injector pulse length.

Your right the Bentley  timing procedure on page 28.42  is confusing.
 Heres how I've translated their instructions.  The basic idea is to
start a warm  motor, raise the rpm to 2400 RPM, see note 1;  then remove
the wiring harness connector from the Temp II sensor (see note below);
then hold the timing light and check or adjust timing until  the V-notch
is lined up with the crankcase seam which is 5 degrees BTDC + or 1
degree. The half moon shape is TDC.

Next Bently's advice seems to say that with a properly set timing, the
max advance is 40 degees when the engine is operating above 3000 RPM.
 There math is:

 Final timing in degrees before TDC @ 3000 Rpm( full advance)
          minus the idle timing should equal 35 degrees + or - 5
degrees. If the final advance was 40 degrees then subtract the idle
timing of  5 degrees  = 35 degrees of  ADVANCE by the distrubtor  is
being added. Pretty confusing.

My translation below:

So in theory the possible tolerance  range of max timing advance would
be: -34 to - 46 degrees. I made a guage  with three marks at 0 degrees,
-5 degrees and -46 degrees. While holding the guage's -5 and 0 degree
marks over the crankshaft pulley marks I marked and  then notched  the
crankshaft pulley at - 46 degrees before TDC.

To check for optimum timing re-connect the Temp II sensor; operate the
engine at 3000 Rpm; use the timing light  to verify what maximum advance
is being achieved by comparing the -46 degree notch with the crankcase
split mark.  I prefer to run as close to this as possible to wring every
possible horse from the motor.


Note1-- I put a nickle or a quarter coin between the idle stop and the
throttle valve to hold the rpm above 2000 Rpm.

Note 2 --I found it best to disconnect the harness connector first
without the engine running, as it takes some dexiterity to press the
wire bale and then wiggle the thing off.  Onec you've done that push the
connector back on, but don't fully seat it. The start the motor for the
timing test, and you'll be able to remove the connector with ease.




Sincerely,

Mark Keller
91 Carat