[Vwdiesel] Black smoke - low power

[Dana Morphew]

"Pinning the pump" and checking the TDC notch on the flywheel are ballpark measures
to get you on the correct tooth of the belt.  The fine tuning comes when you set the
pump timing.  Once you have the belt on and tensioner tightened, recheck the notch
on the flywheel and remove the pin.  Set pump timing next by getting as close to the
center of the TDC notch as possible before reading your gauge.

My thought on pump timing (all things being equal) is to retard it as the
compression is lower.  If you have around 500 on all four, go for .98 mm.(again this
is with my '82 pump).  If the compression is around 400, try .85 mm..  As the engine
has lower compression it is that much later in the stroke that the combustion temp
is reached.  You want most of the combustion to occur after TDC.

Check your valve timing too if you haven't yet.  This will have some effect on the
powerband rpm.

Dana

Jim Arnott wrote:

> So the question logically arises... Do I set the pump for the motor or
> for the pump?  Vanagon spec (pump) .86mm +/- .02 or the Rabbit spec
> (motor) .92mm
>
> And repeating an earlier question, should I pin the pump pulley to
> assure TDC? (Rotate back, zero, rotate to TDC, pin, adjust timing.) The
> TDC notch is a quarter inch wide! Parallax makes it difficult to
> determine just exactly when it's at TDC.
>
> Jim
>
>
>
> Harmon Seaver wrote:
>
>> On Sun, Aug 11, 2002 at 08:15:15PM -0700, Jim Arnott wrote:
>>
>>> Not on the list...
>>>
>>> 0-460-494-102
>>> VE R 48-2
>>> 068 130 108K
>>>
>>> When I rechecked the timing this afternoon, I found it at .95, I backed
>>> it down .82mm.  Is that advancing or retarding the pump?  Bentley says
>>> Vanagon spec is .78-.88 with optimum setting @ .86 +/- .02
>>
>>
>>
>>    You're going the wrong way. More advance -- more degrees.
>>
>
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