Engines don't just randomly stop working.
Timing doesn't randomly jump either.
If it was running as it should have been before you pulled the engine, then something either wasn't installed correctly, or was broken in the process.


How are you figuring that it is 180 degrees off?
Are you saying the cams are 180 off? Or the dizzy is 180 off?
Are you checking it at TDC on the compression stroke?

Did you remember to plug in the distributor? The plug on the side of it?
Given the symptoms and the codes, it sounds like the CAS in the dizzy is the problem. Either the plug itself is bad, which happens rather often, especially with unplugging and plugging it in a few times. Or the sensor has gone bad. Which it isn't as common, but it does happen.

diagnostic procedure for code 11 starts on page 93 start with, and solve this first as the solution could solve both issues.
http://www.nicoclub.com/FSM/240sx/91-94/EC.pdf
code 21 starts on page 104.