Spark Plugs - pre ignition issue

[vwtype53 at yahoo.com (Benjamin Harder)]

--- Bradley Peet <btpeet@effervescent.com> wrote:
> Sounds like you are right on the threshold, though, and -- I know it's
> frustrating -- but 2 degrees of timing should not be a night and day
> difference.  Is there any possibility the timing is not set where you think
> it is or the advance is somehow too aggressive?

 Yes, it is possible that I am thinking the timing is at 6-8 degrees when it is
really actually at 10-12 or something.  I say this due to the cams... the car
idles with quite a lump at 1000 rpm where I check the timing.  With the timing
light looking at the timing mark on the flywheel, the 6 degree mark jumps
around a lot... but usually settles enough to observe the mark as being set
at 6-8 degrees.

Just setting the timing by feel, it *feels* good  when the mark is around 
6-8 degrees and not as rev-happy around 4-6 degrees... so feel tells me that I
have the timing where I "need" it to be, but that is where it pings!
Which is why I thought of running a  colder  rated plug to help dissipate
heat in the combustion chamber... seemed like a good idea since I have
no other solutions right now.  :(

Thanks for the input Bradley!


=====
Benjamin Harder
86 Scirocco 16v
80 Scirocco 16v
93 Passat GLX

http://www.geocities.com/vwtype53/

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