Mongo

Really? That is impressive! the Electromotive guys know their stuff.

Lizard928

The other manual way to listen for knock is the fold a copper pipe up a couple times, then drill a hole through leaving 1 end open. Put a hose over the open end and then put the hose up to a set of covering ear protection. You will be able to hear knocks as well.

Little more ghetto than entropy's way, but works well in a pinch.

Martin's928

"...knock sensor and put on a long cable with a mono headphone jack on the other end. That plugs in to the external microphone jack on a laptop computer."

Ok, I'm going to try that when I'm back on the road with the car. Snow has to melt first…..maybe beginning April…and I'll have a go.

Thanks!

Carl Fausett

I was shown how to take the big-*** screwdriver from the toolbox and hold the handle up to my ear, other end on the block. You can locate a noisy tappet at idle that way, can hear it clearly. But if the engine was doing a pull, you cant separate the sounds at all.

entropy_engineering

Solid lifters, loose fitting (2618 alloy) forged pistons, etc. can make it difficult to hear, especially at high rpm. i had a a buddy getting inappropriate knock retard once we traced to a turbo down pipe just barely rattling against the sway bar under full throttle runs as the mounts flexed. The gold wave software is handy for this because once you can isolate the knock frequency at lower rpm; it never changes regardless of engine speed or load, so it can be filtered out from the other noises. Their is a very interesting article about this published by Motec. One thing interesting is they showed how adding a full racing roll cage and solid mounts to a Mitsubishi Evo rally car actually changed the knock frequency. The difference in weight and stiffness to some degree between manifolds, engine mounts, flywheel weight/material, etc. can alter the exact pitch it rings at.