Knock sensor on M20 engine

[BertjeConti]

I want to mount a knock sensor on my M20 engine, but ofcourse it doesn't have a suitable mounting area on the crankcase.

One thing i defenetly don't want to do is drill a hole in the crank case, so i came with another solution.
I made a mounting plate for the knock sensor.
This mouting plate i want to glue with J-B Weld to the crank case above the starter motor. J-B weld should be as strong as metal, heat resistant, chemical resistant, but would this solution transfer the knock sounds to the knock sensor?



What do you guys think about it?

[nas80]

I think location is vital. Where you going to mount it exactly? I'd follow what bmw did with the m5x and mount in the same equivalent locations

using my "man science" I theorise chemical metal dries very hard so it wouldn't have any sound absorption.

[BertjeConti]

The position i planned for the knock sensor is at the intake side on the crankcase . Near cylinder 4 as high as possible. So as near as possible to the cylinder head.

[BertjeConti]

Mounting plate for knock sensor glued on its place.

Its near cylinder nr2, behind the distributor and fuelpump which will be unemployed soon:



and with the knock sensor in place:

[hairyscreech]

I can chip in a little on this.

One improtant thing to mention is that the knock sound will ring differently in different materials.
An alu block will sound different to an iron block. Thus it is important to calibrate the sensor to the block either by sensor or ecu setup.

Jb weld should transmit sound ok but it will change the sound.
What ecu are you using to pick this up?

[BertjeConti]

I've designed my own knock sensing circuit which is hooked up to a megasquirt based ecu.

Engine is now running with this ecu, ignition only at the moment.
It is very hard to get this engine into 'knock', i have tried ignition advance up to 45 deg. but it wont knock. Running very rich on its carbs will be the cause i gues.