So I've had this noise from my engine for awhile... familiar to anyone who's read my threads before. I take the car to one of the better shops around, and they tear it down a bunch of times, come up with all sorts of theories. There's an inconsistancy though. They check the bearings, find two switched caps, switch them back to normal, and the noise is still there. They find an oil jet hitting a piston, so they take it out and the noise goes away (but oil gets everywhere and the pressure drops dramatically). They put the jet back in but turn it so that it doesn't contact the piston, and the noise comes back. The guy then checks out my pistons and notices that there is no lower skirt. Basically the upper skirt and where the rings are is the only place the piston is contacting the cylinder. The Wiseco pistons I have don't have the skirt, although most JE pistons and others do. The shops buys off on the theory that its piston slap at BDC, when the bottom of the piston clears the bottom of the cylinder. I get sold on it too, until I get the car home.
What was once tapping is now a rattling (like marbles in a glass jar) when I step on the gas. When I let off of the gas it goes away. Also when I first start the car up, for about 15-30 seconds it goes away. I then remembered that the guy said my oil pressure went very low with the jet removed. Now, these three events (jet removed, decelleration, starting up) all have something in common... low oil pressures. What I'm trying to figure out though, is what in the engine would rattle with normal oil pressure, and not with low? I could see the opposite being true... a rattle with low oil pressure, and when everything got lubricated, it going away... but not this way.
Am I just sort of throwing darts on this one, or does any of this sound feasible? Better yet, has anyone had this problem before? Let me know your ideas on this, they'd be much appreciated.

 

Possibly related to missing a head oil control orriface? I was looking over the Helms manual today for all the pieces and parts involved in engine lubrication, and I don't remember ever seeing this little guy when we put the engine back together. A shop had the head off too, and I would think they'd catch something like that... but then again.
I know the intake and exhuast rocker shaft orrifaces are in place, simply because we went to extraordinarily tight security with them.

 

Do you have an oil pressure guage in the car? Mechanical or otherwise?

 

Is the pressure reading that comes off of the oil pressure switch near the oil filter a voltage (0v-5v depending on the pressure), or is it a latch (ie. pressure below 10psi, it latchs the light on)? Thats all I have. If I could get my laptop working, I'd hook it into the ecm and be able to tell you better. I could probably also borrow a pressure gage from work. Whats your thought?

 

the stock sending unit is a latch, i think

 

yep

 

It really does sound like one o your rod bearing are going out.

 

No no no... no no no... noo noo NO!

I had another guy back me up when I installed them. The bearings were pulled twice by me on subsequent occasions and checked with .001" clearance, with another guy verifying it. Then I took it to a shop and they did the same thing, then replaced the bearings anyways. I don't know what the problem is, but one thing I know for sure is that its not the ****ing bearings.

 

Both main and rod bearings have been checked??? Its rattling my brain also now. Another possibility which is rare on "honda" vechicles is the oil pump clearace going out but Im not sure how much of an audioable noise it would make