wrote in message
...
On Thu, 10 Jun 2010 19:45:38 -0700 (PDT),
wrote:

On Jun 8, 5:59 am, brian whatcott wrote:
Jerry Wass wrote:
Where is the best location to mount a knock detector on a 4 cyl
Continental---(4each,O-470 jugs--314CID )

The knee jerk response would be on the hot cylinder at the back!

Brian W

The knock sensor is to detect detonation, which occurs in the upper
combustion chamber. Knock sensors should go on the heads.

But what good are knock sensors unless you're using electronic
ignition with variable timing? Is that what the OP is using?

Dan
Knock sensors on automotive engines are virtually NEVER on the heads.
On the crankcase thy catch the knock amplified by the clearance on the
"big end" of the connecting rod and/or the knock through the cyl wall.

That's really quite interesting, as I really never knew where they were
placed. But it suggests by inference that, at some time past, the
automotive manufacturers outfitted a few similar engines with a number of
knock sensors in various places and then found the locations which gave the
best sensing and the least variation between the cylinders. That should
have been fairly simple in the lab, especially when they intended to
manufacture thousands of identical engines, as they would only have needed
to vary the ignition timing for all cylinders together and vary the mixtures
for the cylinders individually--which should be easy with individual port
ingection.

Peter