Knock sensor

Dont know. Till recently I thought it was a very complicated thing to figure out and get to work properly (like only in a lab). I now read that there are multiple vendors that sell a universal one. Not sure if I believe it or not. Its logical to me that you would have to do some experimenting and tuning to get it in an optimum location so it picks up as soon as possible but does not false trigger from other normal noises. From what I gather the aftermarket ones are just to keep you from instantly blowing up a boosted engine. I somehow doubt they are good enough to work like the factory designed and located ones where they can keep it adjusted to ride just on the edge of detonation all the time.
 
The Aussie crossflow engines mounted a sensor on one of the forward cylinder head bolts. A similar arrangement might work well, but since you don't have any finite data you'll need a tunable system to be able to adjust the response. And l think most sensors require some additional electronics to convert the signal from the sensor into something that the ECU can use.
 
FWIW, GM 3800 Series II have 2, one on each side in the middle of the block, just below the exhaust manifolds - they screw into the water jacket...
 
I read the instructions for one of the aftermarket sets and I believe it also recommended a cooling port. I wonder if that is because the cylinder walls are much thinner than the heads? You would think the liquid would dampen things but maybe at those frequencies it helps by damping out other sounds?
 
I was thinking it might be because sound travels faster through a solid than through air, thus the signal a knock sensor was listening for would be stronger and arrive a fraction of a second sooner.

Plus if the sensor was in the water jacket seems like the sensor would be closer to the noise source.
 
I mounted mine on one of the bolt holes previously used to mount the brackets for the power steering pump braces. It is on the drivers side of the engine towards the front. The sensor and signal converter I purchase let's you adjust the gain of the signal and appears to work well. I have to get the throttle body finished so I stop leaning out the engine to be sure. Whenever I get time to work on it again I'll take some pictures.
Greg
 
Greg":1fpy714u said:
I mounted mine on one of the bolt holes previously used to mount the brackets for the power steering pump braces. It is on the drivers side of the engine towards the front. The sensor and signal converter I purchase let's you adjust the gain of the signal and appears to work well. I have to get the throttle body finished so I stop leaning out the engine to be sure. Whenever I get time to work on it again I'll take some pictures.
Greg


Any progress?

Can you list the part used?

Thanks
 
Here is the knock setup that I have.
http://www.viatrack.ca/

In the MGB with its solid lifters, there was too much noise for the sensor to work. I have pulled this thing out of the MGB and will be putting it on the 300 after the machine shop returns my block. My hope is that the hydraulic lifter 300 will be quiet enough for the sensor to work.
 
There is a sensitivity adjustment on the knock sensor I used (http://www.viatrack.ca/) and it seems to work. Althou, when I get up in the RPMs it knocks all the time. I'm not sure if it is the engine leaning out or the noise in the engine. I do not have megasquirt controlling fuel and no o2 sensor. You can configure megasquirt to ignore the knock sensor over a specific RPM. It is ough to determine what is knock and what is noise in the engine. I think my issue at high RPMs is noise in the engine as I have dialed back the timing and still get the knock indication.

Greg
 
When I did mine, I used the coomon 60 pin plug EEC 4 Ford Falcon XF 1986 to 1991 E6RF-12A69BA item, which looks similar to the old EEC3 and EEC4 Panther platform items for 302 and 351 from 1981 to 1991. It mounts on the common earth strap for the log head bolt number one, US drivers side front bolt. The Alloy head bolt, also used on Classic Inlines engines, is about 0.875" taller, but uses the same sensor bolt as my 1972 XA Falcon engine.

The sensor is Fig 13 on the Page 221 Tomco website listing http://www.tomco-inc.com/Catalog/knock%20sensors.pdf, looks the same as the F150 4.9 six as well. Tomco 22 or 42 (29022 and 29042)

Tomco listes them differently to Standard Parts #KSxx listings, but the Ford knock sensor was the first to the US market in 1981 as a type 21 item, Tomco part number 290021.

The Aussie ford item just polls an on off 3 volt signal back to the EEC4, and that cuts the TFI timing back.
 
fordconvert":b1tpo74c said:
I read the instructions for one of the aftermarket sets and I believe it also recommended a cooling port. I wonder if that is because the cylinder walls are much thinner than the heads? You would think the liquid would dampen things but maybe at those frequencies it helps by damping out other sounds?

actually sound travels faster in water than in air. back in world war two, submarines would fire torpedos when running on the surface, those on the conning tower would watch the runs, and see the explosions, and at the same time the explosions would occur, the sonar operator would sound off "HIT", long before the sound of the hit reached the sub.
 
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