I own 2 D16z6 engines. Engine #1 came with my '95 Del Sol when i bought it (used) and engine #2 i purchased off craigs list when i threw a rod in engine #1. Well, not to long ago i spun a bearing in #2 and am now in the process of a rebuild.

The problem i have is, the two oil pans look different, though both engines are marked as being D16z6. The oil pickup off of #2 also sits about 1/4" deeper than the one off of #1. Im thinking that one of the engines was rebuilt with different parts or off of a different civic, but not sure how to identify what pan originally comes on the '95 Del Sol d16z6.

Engine #1 on left
Engine #2 on right

 

are there any stamps on either? As long as the pickup tubes mate to the oil pump correctly, and bolt up and pick oil up fine, I wouldn't worry about it. People swap parts on these motors all the time.

If I were you, I'd just pick whichever one is larger or better shape and use it to rebuild one good motor. If you have a good crank, pick 4 good rods, new bearings and rings, deglaze the cylinders and try it again.