Kamikaze

What is it exactly that makes an engine knock when the bearings are bad? Is it the bearings spinning and the tabs hitting?

shortyz

isnt knocking pre-ignition. (not sure)

88crxSi

That's detonation As for knocking, I dont know what causes it exactly.

Semnos

I think knocking has to do with detonation.
If your engine is knocking then it is detonating...that's why they made the knock sensor so when knocking accures it retards your ignition timing.
I hope I didn't just write dumb *** ----.
Because I sometimes mix things up hehehehe

Rolla1990

You could also have a "rod knock" where the bearings on the big end of your connecting rods are worn, it starts making noise at certain rpm's and loads.

Semnos

What up Rolla?
You got your new Clutch?

Kamikaze

Yeah I'm pretty sure it's what rolla said about the rod knock at higher rpms. I know when the rod bearings are worn out it makes that knocking sound, but I was wondering what exactly makes the sound. Does anyone know if the crank bearings being bad would make the knocking sound too. I know if your valve clearance haven't been adjusted for a very long time it also makes a knocking sound too.

Special FX

A lot of times, you hear a rattle-type knock when the bearings ---- up, but usually if they are very worn, you are hearing the piston hit the cylinder head around the squish rim. This is especially true on engines with closed-chamber heads and factory flattop pistons.

Kamikaze

So if this occures over a long period of time isn't your head pretty much ruined?

Rolla1990

---- yeah! Its an eight puck! wooooooot! I had no idea that it would be an eight puck clutch. Very, very tough looking. Its the strongest clutch centerforce makes for my car. BTW- I'm gettin' my new engine on Friday!