Re: 2.0L 8v Questions

[Dan Bubb <jdbubb@ix.netcom.com>]

I've read in a number of places that mechanical noise can effect knock
sensors. Apparently, the interference typically happens at higher RPM
when the mechanical noise approaches the frequency where the KS
operates.
On the other hand I've run a KS ignition with a solid lifter head. (as
does Andrew Stauffer who recently pulled 123 HP at the wheels on a
Mustang dyno with his 2.0 L 8V) I've also swapped back to the stock
ignition on occasion and can say with authority that the KS ignition
gave more power while it also clearly eliminated knock just like it's
supposed to.
Clearly, incorrect valve adjustment or worn valve guides or tappet bores
will make enough noise to make the KS retard the timing. Also,
significant vacuum leaks that cause the engine to run lean (and
therefore want to ping all the time) will retard the timing.
One way to reduce KS sensitivity is to put aluminum washers on both
sides of the sensor then retorque.
Obviously, correct torque on the sensor bolt is critical. If I remember
correctly, it is 7-9 ft-lb.
Dan
 

Doctor Dubsalot wrote:
> 
> Steve:
> I'm very interested in your statement about a knock
> sensing ignition system working on a solid lifter
> engine. I installed a complete 86 gti ignition on my
> 2L 8v engine, observing the correct knock sensor
> torque as per bentley manual. long story short, i was
> plagued with detonation. I completely trouble shot the
> whole system, as per the bentley manual. No faults
> found. I then removed the complete system from a car
> known to be good and tried that. Same deal. I then
> installed a non knock sensing system, and it ran fine.
> I can only conclude from my own experience that a
> knock sensing system doesn't work well with
> mechanical lifter. If you could direct me to any
> information regarding modifications that might allow a
> solid lifer/knock sensing setup to work, I'd greatly
> appreciate it.  Thanks!
> Dr. Dubsalot
> 
> Merry Christmas!
> 
> On Tue, 18 Dec 2001, Doctor Dubsalot wrote:
> 
> > head is Hydraulic. Using the hydraulic head will
> allow
> > one to utilize a knock sensing ignition system from
> > say, an 85 golf gti. With this setup, you can run
> your
> 
> I have heard, from a number of sources, that one can
> use knock sensing
> ignition with a mechanical head. the knock sensors
> bolt low on the
> block
> and filter out everything except teh frequency they
> monitor, which is
> very
> different from the frequency of valvetrain noise.
> 
> No personal experience in this area, but the
> explanations i have heard
> make sense to me. so, i'd put knock sensing in a car
> with mechanical
> lifters, for sure.
> 
> take care,
> 
> Steve
> 
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