I just had my 91 Accord timing belts replaced after 222,000. After driving it for a few days, my oil pressure bottoms out after a few minutes of driving. Checked with pressure gauge. 70psi at start up. - after reving at 3krpm pressure would fall to under 10psi. Changed oil and filter, but same result. Removed oil sending tube and noticed sludge and fragments of plastic and rubber ran out. Could this be a blown seal or worn oil pump. I've heard that Honda oil pumps are bullet proof. Anyone ever had this problem. A solution? An answer?

 

I am not sure how plastic pieces can find their way into the oil passages.

Excessive bearing clearance will give you low oil pressure at normal operating temperatures.

 

Changing the timing belt should effect any of that at all!
check the tranny side oil seal.. see if there is oil leaking from there..
you should be able to see the oil pump side pretty easily.
the oil pump is actually a metal gear... so there is really no plastic except the seals and silicone sealant.
are you sure you are not seaing bearing pieces or pieces of silicon/oil pan gasket when you pulled your pan?