521 locking gas cap ?

[sergio521]

Wondering if anyone knew where I can get a locking gas cap or do something to lock my gas cap for the 521 any help will be appreciated

[thisismatt]

Either find a fuel door lock (was an option on the 521), or you can buy a Stant G-764 or G-764E.  Search ebay for Stant (764,G-764,764E,G-764E)

[DanielC]

You should be able to find a standard gas cap that will fit at a good auto parts store.  Be aware, there were two different gas caps that I know of that were used on a 521.  Early L-16/521 trucks did not have a evaporative emission system, then California 521 trucks got the system, and later all USA trucks had evaporative emissions systems.  If your truck had evaporative emission control, the easiest way to tell is a square box in front of the left rear wheel well, in the bed.

Evaporative emission gas caps were sealed.  They DO NOT allow air into the gas tank as the gas is used.  If you put an evaporative emission cap on an earlier 521, it will seal the gas tank, and the engine will starve for gas, or worse, it could collapse the gas tank.

Datsun actually had a locking gas cap door as an option for 521 trucks.

[sergio521]

Okay so i have an emissions system still on the 521 so I should look for one that doesn't vap though the gas cap i will need one that seals all the vapor in the gas tank