knock sensor mounting on a TC engine

[Robert]

Hello Guy,

Ther's a while I did not ask for some information...

If you want to monitor the knock on a 130 TC engine, where do you mount the sensor ? Indeed there is no fixing point like we can find on other blocks near the head on top of the block. I plan to use a Bosch sensor with a 8 mm screw but I don't want to drill the block !!!
Do you have an idea from your experience ?

Thank you,

Robert

[Guy Croft]

Robert, hi

All I can really reliably tell you about this is that knock sensors were used on the Integrale 8V and others, and the sensor was mounted in a boss in the same location as one of the cyl head temperature senders.

Whether you will pick up knock at all or be able interpret knock correctly is a very good question. Tuning the device to filter the knock frequencies that don't actually matter is a pretty difficult undertaking.

Insofar as your twin-carb engine is concerned it's pretty knock-resistant anyway. It will only knock if you:

1. Use low octane fuel
2. Draw hot intake air
3. Run the engine too hot
4. Use the wrong grade of plugs (you should be on NGK B9EGV race grade)
5. Run the ignition out of spec (either over-advanced or retarded can lead to overheating of the combustion chamber)
6. Use a silencer system with high back pressure - though of course this usually shows up in the early stages when you cannot jet the engine up properly and the unit won't accelerate freely (on or off load).

G

[Robert]

Hi Guy,

Thank you for your prompt reply !!

I confess I thought to this location but now I know how to do. Not sure I will try...
In fact I did an audio amplifier with sensor as microphone and I would try it on my engine...

It is for a friend who wants listen to the noise and knock during tuning of engine on dyno. I (and he) know that the knock occurs only inside a window starting before TDC and has a specific frequency. May be I will undertake electronics with the following "flow diagram": pre-amplifier, ajustable band pass filter, peak detector, LED bar graph. This signal path is windowed (around 60° of the cycle).

Regards,

Robert