Distinguishing Knock from Mechanical Noise

Hi guys, after some advice with how you guys deal with mechanically noisy engines where its hard to hear exactly what is going on?

This is one of those situations I guess where you fall back on your experience, but if you're like me you don't tune cars day-in day-out, you won't necessarily have that!

I use Plex V1. Quite often I hear what I believe must be mechanical noise, which appears around the knock frequency, approx 2/3 rpm range ticking / buzzing and can't be removed by pulling any amount of timing. Switching between 1st & 2nd harmonic doesn't help if the noise is at or around the knock frequency. So this leaves me then with zero confidence and it's frustrating - so do you guys have any tips & tricks for working around this?

I also find it difficult to induce light knock under "safe" conditions with boosted engines with relatively low compression - what I mean is, to generate knock conditions at lower rpm/load to establish a baseline for knock vs noise and to get "tuned in" to the engines own knock sound.

So what do you guys do? Practical real world experience please, not theory :D

Hello i use plug reading and dyno figures to play it safe. i tune several engines a month like this, it used to scare me a lot but after 30 years I've got used to it, often shifting the knock sensor to the head will help also

Hi Ross,

Thanks - I’ve often checked plugs for evidence but always been concerned also that light knock not be immediately obvious and go undetected.

So I guess I can only work on the basis that if pulling timing doesn’t make a noticeable change to the noise then it must be mechanical noise and not knock?