questions about high compression 4kq's with NG/NF/Hybrid and CISE

[Derek]

In the continuing saga of this hybrid motor, I've eliminated 95% of the
knocking...
...at the cost of running 0 degrees ignition advance.  Obviously this is not
a solution, as the stock JT motor running 12+ degrees advance probably makes
more power than this does at 0!

Currently,
Ignition: 0 degrees at idle, vacuum advance connected.
Cam: 0 degrees. (triple checked crank/cam/rotor positions)
Fuel: CPR current avg 8mA.
Knock:  Infrequent, and much quieter, but still something's not right.

I spent a couple hours changing cam timing, ignition timing, and fuel, then
running up and down a local freeway.  No compromise would eliminate the
problem and maintain a reasonable level of performance.  If others are able
to get 6-10 degrees of advance out of similar engines, there must be
something pretty seriously wrong with mine, but what?  The only thing coming
to mind is that the mix-n-match pistons from two dead Golfs may not be
ideal.  I took care to locate two HT engines.  On startup, there is a light
tapping noise inside the motor.  It's not lifters, nor big-end bearings, as
I know what they sound like when bad.  The NF doesn't have a vacuum pump and
rod to make noise with.  Could a slightly worn wrist pin have just enough
play to alter compression once warmed up and the oil thins a little?  It's a
long shot, but could fuel delivery/quantiny be an issue here?  If the filter
were clogged or a couple injectors bad and couldn't keep up with flow demand
at high load and rpm, would it knock, or stumble and miss?

Thanks again for your replies.  Anyone have a NF, NG, or KH near seattle for
cheap? :-)
-Derek
'85 4kq  '86 4ktq  '87 Gti16v