Knock sensing vs gear driven cam

[kjones6039]

383 sbc with gear driven camshaft. Actually very quiet compared to some I have seen/heard! This is a Pete Jackson unit and they claim that it is their quietest gear set.

Am I barking up the wrong tree to even consider this?

Ken

[dontz125]

I will hereby flaunt and proclaim my blissful ignorance and ask, What the heck does pondering a quiet cam gear train have to do with knock sensing? I understand that knock can get masked by engine noise, particularly tappets, but how would this involve trees and barking therein?

[elaw]

I think the concern involves not so much masking, as that cam gear (or any other) noise could be mistaken as knock by the system.

IMHO the only real way to answer this question is trial-and-error. Mount some knock sensors on your engine, preferably on the outside of the block so they're away from the camshaft. Then set your spark advance table to very conservative numbers so there's no chance of the engine knocking. Take it out for a drive, trying to hit many different RPMs, while datalogging so you can get a "baseline" of the knock sensors' output just from engine noise.

Then reset your timing to something that will cause knock, and carefully go for another drive while datalogging.

If you can see a clear difference between the knock values in the second vs. the first log, you'll likely have success with knock sensing. Otherwise probably not.

Of course I'm ignoring quite a few things in the above, like knock window and frequency settings, variations with engine temperature, and so on...

[kjones6039]

but how would this involve trees and barking therein?

That was my attempt to avoid using a more terse, and possibly prohibited term!

I think the concern involves not so much masking, as that cam gear (or any other) noise could be mistaken as knock by the system.

Correct! Somewhere along the line I read about this topic but can't seem to find it now. It concerned the clicking and clacking of the gear set, that might trigger the knock sensor. And, of course, if I read it on the internet it must be true!

IMHO the only real way to answer this question is trial-and-error. Mount some knock sensors on your engine, preferably on the outside of the block so they're away from the camshaft.

Trial-and-error works for me as long I get more trial than error! I have a stock sensor to install, and would intend to install it in the stock location, to try it out. The GM ICM is a bit pricey for experimentation, but I am willing to bite the bullet and give it a go.

Thanks guys,

Ken