curved flange on the key'd spacer faces, no sure where you are there, sure crank front but where there? its sandwitch of parts at what step did you find this alien part?
this?
http://www.fixkick.com/t-belt/snouts/html/image_3.html
the spacer is called and oil sling'er, and belt back stap,
but no 96 made in usa or canada has such a part, there. ever.
the crank cog, in 1996 had the washer removed slinger. and added and integrated OBD2 1996 tone wheel (spikey thing)
what is engine serial number?
evolution of bottom cog
washer on rear.
then they integrated washer to cog 1995, vin code engine serial G16Smnnnn S=1995
then in 1996 OBD2 became law in USA (only) and the code is not with spikes (tone wheel for CKP crank sensor) engine serial G16Tnnnn 1997 or T , V or W codes 96 to 98 engines.
back side of 96 + sidekicks tracker, USA only , avoid the one on the right.
http://www.fixkick.com/t-belt/snouts/html/image_16.html
that bolt probably never once was set to factory torque setting so is like new.
the bolt acts as spring, length wise. the key way is only for timing and has no function for straighth to hold time.
the answer is that curved washer has no use on any USA car 1996 to 1998 G16bs
ever. so must be wrong engine or other person mixed parts off a 92 to 94? engine.
your 96 has this, a ckp and any washer there would make the tone wheel fail hard.
is this sensor missing too.?
http://www.fixkick.com/my96-16v/ckp-sensor.jpg