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Lettering on M 38
Posted: Thu Apr 09, 2009 9:14 am
by DocUwe
Hello,
can s.o. tell me what does the following lettering means:

I found this pic in the historic album here.
2nd question: " Caution do not overfill allow for expansion ":
When was this painted, in the factory or in the field? Has the "C" of Caution one horizontal or 2 vertical strikes?
Thanks for answering and for lend out of the albums

Posted: Thu Apr 09, 2009 4:41 pm
by OKCM38CDN
This is a warning that when full the fuel in the tank may expand and cause spillage from the fuel tank.
This was generally done after the unit recieved the vehicle if I am correct...
The lettering was just a standard stencil...
Hope this helps...
Posted: Thu Apr 09, 2009 8:07 pm
by Ryan_Miller
This has to do with the vent fording system.
The vent for the fuel tank ran to the air cleaner. There is a small valve in the tank pickup assembly where the vent line connects to it. When the jeep runs it sucks air out of the tank and vents the tank. When not running it tended to allow pressure to build up. Some times when the tank cap was opened it would gush out or worse yet it would go up the vent line to the air cleaner.
Posted: Thu Apr 09, 2009 11:07 pm
by maeserik
The gascap has a ventilation also ? Is these set to close during submerging ?
Erik
Posted: Fri Apr 10, 2009 9:11 am
by SteveJ
As far as the stencilling of the letters goes. Ive only seen 1950's military ones with the two verticle bars in the C not a horizontal bar. I think it might be a civy stencil but I may be wrong.
Here is a good website
http://www.militarystencils.com/
Posted: Sat Apr 11, 2009 7:43 am
by Jim
In the first photo, with the machine gun, what is the
photo location? It says "West Virginia coal country"
to me. Was this in relation to a strike?
Jim in Darkest Arkansas
Mena tornado missed us by 60 miles or so...
Posted: Sat Apr 11, 2009 7:46 am
by Ryan_Miller
Hazard County KY coal strike
The early M38 gas caps did not have a vent inside which allowed pressure to build up on a warm day.
Posted: Sun Apr 12, 2009 2:50 am
by wesk
We are getting fuel temperature caused expansion confused with the tank's venting system. They are interrelated but they are seperate issues.
The warning "Allow for expansion" means do not fill it all the way to the cap. In almost all cases the fuel coming from the storage system is quite cool compared to the ambient outside temp. So the fuel will expand in volume as it warms up.
There are several caps used throughout M38 production and there was a lot of cap mixing going on. The non-vented cap was used to prevent water from entering the tank during fording operation. There was a manual selectable cap that allowed you to mechnically select vented or unvented. No matter which cap you use the tank relies on it's primary vent system which is the tube running from the pickup adapter on the tank to the air cleaner. Unless this tub gets inadvertantly plugged the tank is always vented irregardless of weather the cap is or is not.