[Vwdiesel] hillbilly tuning
scameron at compmore.net
Sat Apr 9 12:02:37 EDT 2005
At 10:26 PM 4/8/05 -0400, you wrote:
>Thanks, so that means you look at the IP mount as you move it to determine
>the distance moved?
There are 2 bolts accessed throught the sprocket
(you have to remove the belt cover and set the engine to TDC to get at them)
Goes without saying, but, "always double check you have not left a wrench
hanging on one of these, or a peg stuck in the timing hole in the sprocket
before starting the engine"!
A third bolt on the front flange is in backwards and is accessed from the
outside, on the front of the flange facing you as you lean over the front of
There is a 4th bolt at the back end (where the outlet pipes go to the
injectors) down low and toward the engine block, actually under the pump.
I can do pix if you do not have a Bentley.
All these bolts go through slotted holes, so when loosened, the pump can be
rotated a little.
There is a stamped "boss"), or line or mark, pressed into the belt cover
back plate near the top of the pump. This more or less lines up with the
notch in the "front" (pass. side end) edge of the sprocket when the engine
is at TDC.
There is also a raised ridge cast in to the aluminum of the pump body at the
top front end (sprocket end) which more or less lines up with these marks.
Before moving the pump, scribe a mark on the mounting plate where the flange
meets it, and a match mark on the aluminum pump flange, so you can tell how
far you moved it. This is where the "pencil line" 1mm increments will be
Rotating the pump forward (top toward the front of the car) retards timing,
and backward toward the engine advances the timing (early).
Late will make the engine hard to start cold, but very quiet idling, and
early will result in loud clattering and is hard on the engine and head gasket.
Serendipity is somewhere between the 2.
When I was a kid, I had a 1929 jaloppy, (gas) that had a "spark" control on
the steering wheel that would be set to "retard" for starting, and to avoid
a broken arm if hand cranking.
Had to remember to set it back to advance for running, or it would overheat.
Also. once I had a bit of experience, I could tune the spark timing for best
running, a little retarded for lugging up hills, more advanced for
economical level ground cruising.
Thats all done by the computer nowadays. In the middle years it was done by
a vacuum servo operated by intake manifold vacuum.
Hagar and I bemoan how we have lost touch with the ghost in the machine.
Automation has taken it all away from us.
We have an intuitive understanding of how they work, so everything is done
with a "pencil line" a "calibrated wrist", etc.
Never ask how many bolts I sheared calibrating the wrist.
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