Knock Sensor Mount 400B Engine Holley Terminator X

[Roman1970RR]

Hello all,

Has anyone mounted a knock sensor to a 400B block? If so how and where? Only place i can find is at the top of the block front face. It is supposed to be between the middle cylynders a little low so no valvetrain noise. Any ideas?

 

[PurpleBeeper]

How does it attach? The side of the block seems like the place if possible

 

[Roman1970RR]

How does it attach? The side of the block seems like the place if possible

They bolt to the block but we don’t have spare blind holes. I’ve heard of people making brackets but I don’t understand how you’d make one with zero vibrations to be accurate.

 

[j-c-c-62]

I thought water jacket block drain plugs were acceptable?

 

[Roman1970RR]

I thought water jacket block drain plugs were acceptable?

Are they? I shall research. Has anyone fitted one that’s working?

 

[j-c-c-62]

Are they? I shall research. Has anyone fitted one that’s working?

I have read that on a slant 6 two mounted (front and rear) on the block as mentioned is beneficial, as the ECM is only looking/listening for detonation spikes during a very specific narrow time window, and it ignores all the other mechanical noise before and after per each ignition event.
Let us know your research.

 

[PurpleBeeper]

View attachment 1814772


They bolt to the block but we don’t have spare blind holes. I’ve heard of people making brackets but I don’t understand how you’d make one with zero vibrations to be accurate.

I see no reason why JB Weld wouldn’t work

 

[6872n73]

I used the knock sensor from the old GM 502 marine application that screws into the side the water jacket. It had the closest range for the piston diameter.

 

[j-c-c-62]

I see no reason why JB Weld wouldn’t work

It prevents metal to metal contact?

 

[RJRENTON]

Hello all,

Has anyone mounted a knock sensor to a 400B block? If so how and where? Only place i can find is at the top of the block front face. It is supposed to be between the middle cylynders a little low so no valvetrain noise. Any ideas?

It prevents metal to metal contact?

Do you know what a "knock sensor" is and how it functions and just what data it provides the vehicle's on board computer. A knock sensor is an accelerometer that responds, or generates an electronic pulse based on a vibration induced or "ringing" in an area of the cylinder block that resonates or concentrates the vibration produced by a cylinder detonation (one or all cylinders), due to fuel, spark advance or several factors, specific to a engine assembly....it's NOT in the same location for every engne.....it depends on the resonance of the casting.....not arbitrarily selecting the coolant drain passages/plug.....research where the factory installed the sensor on a similar type of engine.....plus you must know the output of sensor, in terms of 4-20 ma or voltage range and where the signal modifies the spark advance program and then reprogram the computer......it's not a simple plug and play installation....just ny opinion.....
BOB RENTON.

 

[j-c-c-62]

Do you know what a "knock sensor" is and how it functions and just what data it provides the vehicle's on board computer. A knock sensor is an accelerometer that responds, or generates an electronic pulse based on a vibration induced or "ringing" in an area of the cylinder block that resonates or concentrates the vibration produced by a cylinder detonation (one or all cylinders), due to fuel, spark advance or several factors, specific to a engine assembly....it's NOT in the same location for every engne.....it depends on the resonance of the casting.....not arbitrarily selecting the coolant drain passages/plug.....research where the factory installed the sensor on a similar type of engine.....plus you must know the output of sensor, in terms of 4-20 ma or voltage range and where the signal modifies the spark advance program and then reprogram the computer......it's not a simple plug and play installation....just ny opinion.....
BOB RENTON.

I believe this discussion only concerns aftermarket knock sensors/EFI systems. Correct me if I am wrong. We do not have the luxury of extensive testing in labs to decide best location. I disagree with your summation that any detonation induced "ringing" is sought by the ECM to signal detonation in our case. The ECM is looking for a specific waveform spike shape in a mechanical vibration (which is a sound btw, but maybe above or below human range of detection/hearing) caused by detonation at a very specific time during a crankshaft revolution for each cylinder. Might it cause a ringing, sure but that is not the target, ringing is likely filtered out of the signal by the ECM as its not relevant. One can research any engine they want, but for aftermarket users its always going to be a guess. If you guess wrong, you move it. If you add a layer of epoxy between the metals, you risk filtering out what the ECM is looking for in order to detect a detonation spike. If you have on our typical CI old school V8's a better location for dual knock sensors, that is away from as much as possible any noisy valve train, and able to "hear" each bank equally well, without drilling, please share. As goofy as a coolant drain outlet might appear on face value for a sensor location, it might actually be the lessor of any other evils.

 

[Roman1970RR]

I believe this discussion only concerns aftermarket knock sensors/EFI systems. Correct me if I am wrong. We do not have the luxury of extensive testing in labs to decide best location. I disagree with your summation that any detonation induced "ringing" is sought by the ECM to signal detonation in our case. The ECM is looking for a specific waveform spike shape in a mechanical vibration (which is a sound btw, but maybe above or below human range of detection/hearing) caused by detonation at a very specific time during a crankshaft revolution for each cylinder. Might it cause a ringing, sure but that is not the target, ringing is likely filtered out of the signal by the ECM as its not relevant. One can research any engine they want, but for aftermarket users its always going to be a guess. If you guess wrong, you move it. If you add a layer of epoxy between the metals, you risk filtering out what the ECM is looking for in order to detect a detonation spike. If you have on our typical CI old school V8's a better location for dual knock sensors, that is away from as much as possible any noisy valve train, and able to "hear" each bank equally well, without drilling, please share. As goofy as a coolant drain outlet might appear on face value for a sensor location, it might actually be the lessor of any other evils.

Yeah, my understanding is they need calibration and it can be done by installing knock sensor (in whatever location you can find on a block that never had them) turning the sensitivity right down idling the motor and slowly increasing revs and keeping an eye on what the sensor is detecting. At idle there is almost certainly no detonation the ecu learns what the engine sounds like and then once you have a baseline you increase load and sensitivity until you just start getting detonation and from there your knock sensor is calibrated. I also read it should be done using professionals or something but I haven’t got anything like that in my toolbox.

It sounds like it sounds like the glue is out. Here are 2 ideas one was plug suggestion above and the other is longer bolt and extra nut where the top engine mount bolt and dipstick are secured?

Or bit agricultural but what about fabricating a c shaped clamp threaded and clamping to the bottom of the center lug which appears to serve no purpose?

 

[RJRENTON]

I believe this discussion only concerns aftermarket knock sensors/EFI systems. Correct me if I am wrong. We do not have the luxury of extensive testing in labs to decide best location. I disagree with your summation that any detonation induced "ringing" is sought by the ECM to signal detonation in our case. The ECM is looking for a specific waveform spike shape in a mechanical vibration (which is a sound btw, but maybe above or below human range of detection/hearing) caused by detonation at a very specific time during a crankshaft revolution for each cylinder. Might it cause a ringing, sure but that is not the target, ringing is likely filtered out of the signal by the ECM as its not relevant. One can research any engine they want, but for aftermarket users its always going to be a guess. If you guess wrong, you move it. If you add a layer of epoxy between the metals, you risk filtering out what the ECM is looking for in order to detect a detonation spike. If you have on our typical CI old school V8's a better location for dual knock sensors, that is away from as much as possible any noisy valve train, and able to "hear" each bank equally well, without drilling, please share. As goofy as a coolant drain outlet might appear on face value for a sensor location, it might actually be the lessor of any other evils.

I'm well aware of how an accelerometer, aka "knock sensor" is and how it operates. I was speculating as to the location of the device to achieve the greatest accuracy or best performance and provide the repeatable signal, during adverse conditions, for best or desired results. The other issue may be the home installation person and reprogramming of the computer to utilize the knock sensor input in the appropriate sub-routine.....assuming the owner has the original program (or a copy) and knows the how's any why's of how to access it.......just a thought.......
BOB RENTON

 

[j-c-c-62]

Yeah, my understanding is they need calibration and it can be done by installing knock sensor (in whatever location you can find on a block that never had them) turning the sensitivity right down idling the motor and slowly increasing revs and keeping an eye on what the sensor is detecting. At idle there is almost certainly no detonation the ecu learns what the engine sounds like and then once you have a baseline you increase load and sensitivity until you just start getting detonation and from there your knock sensor is calibrated. I also read it should be done using professionals or something but I haven’t got anything like that in my toolbox.

It sounds like it sounds like the glue is out. Here are 2 ideas one was plug suggestion above and the other is longer bolt and extra nut where the top engine mount bolt and dipstick are secured?

Or bit agricultural but what about fabricating a c shaped clamp threaded and clamping to the bottom of the center lug which appears to serve no purpose?

View attachment 1815066

View attachment 1815067

View attachment 1815073

I like that block ear, if it is available on both banks and you willing to drill. I would guess the smoothest/flattest contact surface for the knock sensor no matter where located would be preferred.