Vented or non vented petrol tank cap.

[chevpol]

Hi folks ,

My A2 is currently not running, carburettor away at a friend who runs a garage being looked at, but I noticed that my tank cap says non vented, is this right? Or should ot be a vented one?

Best regards

Mark

[Fil Bonica]

What kind of gas tank?
Emissions on non emissions?

Fil Bonica

[chevpol]

No idea as to type of tank

[W. Winget]

From my memory (which everyone can now jump in to correct )
If the cap has two little fingers sticking outside the round section, it is made to simply be repositioned for fording by turning it a little more, sealing off the tank to outside air. This cap would normally be left in the 1st locking position, allowing air into the tank.

There is also the older provision for a vent bar inside what I believe is the third later version of the A2 cap. Likely because of confusion on how to just not rotate the darn non-vented cap fully closing off the tank. Drivers TM-10 covers it...

Older vented caps had the same small bar inside the top that could be turned to vent or seal the cap, some with welded on tabs on top (or beat down by drivers that tore their pants) or some caps came plain without tabs, thereby preventing tearing of uniforms as soldiers exited the drivers seat.
From memory...V/R W. Winget
Web photos:
151A2 early style, no vent, close to 1st notch (finger) to allow air in:

Note "non-vented" stamped in top


151A2 late style inside option of the bar for venting

Top



Typical M series vehicle vented by rotating the bar inside (early 151's and A1's)

inside, note the bar!

[Tech3140]

Look at the top of your A2 fuel tank. Under the driver’s seat. There should be one big plate with lots of bolts.
Also a smaller plate where a wire plugs into. If that’s all that’s on your tank, it’s a standard tank.
If there a lot of plates and lots of hoses, then it’s an emissions tank and you have a late model A2.

Hope that helps.

[chevpol]

Lots of pipes etc, so thank you, A large model emission one.

[lpcoating]

On the earlier tanks, the fill tube is clocked different for the cap. The later cap with the two fingers interferes and will not lock as one finger hits the filler tube guard.

Notice the notch at the top of the filler neck. One is at 12 and the other at 1. Don't mind where my finger is pointing!





Cap is locked:



Cap will not lock:



Last tidbit: picture of non emissions tank:




Guy