This is what ddgonzal is meaning

http://datsun1200.com/modules/myalbum/photo.php?lid=22032

http://datsun1200.com/modules/myalbum/photo.php?lid=6248

http://datsun1200.com/modules/mediawiki/index.php?title=Doors

Straigten it out and it will work but if it does show to be a lock issue

If you want individual locks check this...

http://www.new-datsun-parts.com/datsun-1200-parts-locks.html

but as you can see they are individual locks and keys which sucks

I did this and just updated it all and all keys work for all locks and ignition

http://www.ebay.com.au/itm/KEY-SET-CY ... ories&hash=item3a7cd3cb80

Unfortunately bprojects did have the door lock mechanism itself but are out of stock currently so hopefully that gives you an idea