Valvoline Motor Oil porcelain sign features the large oil can of Valvoline Motor Oil. This sign measures 12 across and has excellent lettering and porcelain! Whether you are displaying this sign as part of your collection in your man cave, shop, bar, or garage, or giving it as a gift, you can also browse my other auctions for more vintage gas, oil, aviation, automobile, motorcycle, and hunting signs. Vintage Valvoline Motor Oil porcelain sign. 12 inches in diameter. Bright colors w/ porcelain on both sides.