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

[JShadzi at aol.com]

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<<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!>>


Hmm, well, stock JT is 6 degrees, so that's retarded 6 degrees from stock, so
not too bad, but still odd considering my experiences with increasing advance
over stock.  With vac. adv. you're sitting at about 10d BTDC at idle, not
bad.  Few questions, though:

-which ignition system are you running
-which ignition dist. are you running (I assume 4kq since it has vac. adv.)
-which fuel distributor are you using?
-which spark plugs are you running?
-Did you have the head shaved when rebuilt, had it been shaved in the past?
Two head skims could easily bump your compression to 11:1 if not careful.
-Are you using 91 or 92 oct. fuel?

>
> <<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.  >>

Not exactly sure here, but are you positive that the Golf pistons have the
same exact dish profile/volume as the NG/NF?  Were'nt those Golfs 10.5:1
comp?

<<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? >>

Very doubtful, that much movement would cause some other more serious
problems.

<< 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?>>

I doubt that too, detnation is mostly a combination of ignition timing and
compression, detonation from fuel problems only happens if your igniiton is
absolutley optimized, which is not the case, esp. in CIS-E cars.  None the
less, are you monitoring O2 or EGT?

Javad