Stock D16Z6.

I have a pitter patter knock. Started in October (very quiet) and got louder as time went by, I'd say it planed out a couple of months ago.

Thought it was the ISB so I put a backup trans in (unknown condition). Noise didn't go away. Split my trans open tonight and the ISB spins fine, no noises from it. All other trans bearings are good. Throwout bearing was replaced when I put the backup trans on (about 1.5-2 months ago).

Something is wrong with the backup trans as it does not make the noise at idle with clutch in. Let off the clutch and it makes the noise. Does not make the noise while revving the engine with no load (neutral). Noise increases with RPM. Does not sound like loose valve lash or rod knock (definitely doesn't sound like rod knock). The noise is a pitter patter type noise and not like a knock noise. When cruising with the good trans at 80mph I'm at 5k. Noise is very very light (almost un-noticable) at that RPM until I give it gas to pass or when the engine is has a load put on it (going up hills, etc).

Oil doesn't show signs of a spun bearing.

Going to adjust the valves tomorrow morning and swap the trans out tomorrow night as well as replace the pilot bearing (this is one of the places I think it might be coming from) and inspect the clutch (no problems with the clutch just checking it).

So what might it be?

 

My .02
Just the other day we got a car in the shop with a knock clank sound, weird... sounded like the clutch/throwout bearing was bad...turned out to be the flywheel, the gear ring separated from plate causing a distinct noise..and all this time i thought honda made one piece flywheels

 

my gsr has a wierd noise coming from somewhere around the engine bay...no idea what it is...it dont sound like a knock or valves ticking..it sounds like a loose washer raddling...but then again i cant seem to figure it out....car drives good its just annoying not knowing what it is....hopefully its not something with the clutch or pressure plate or anything with the damn motor at all...its not too loud but you can hear it ticking or something...yet its not the valves either

 

Any ideas? Going to do the trans now. Need this taken care of before Friday or I'll have to find a longblock and get it in before Sunday.

 

pilot bearing had a few cars do it already it gets dry and makes the dumbest noises