Published at Tuesday, August 14th 2018, 15:08:54 PM by Martha Mcgowan. Air Compressor. For the people who want a more powerful model, there is Westward 4B220 portable air compressor. This machine uses a powerful Briggs engine. Its powered by a powerful 5.5 HP motor. The machine uses a 2 cylinder pump made of cast iron. It has a horizontally placed tank which has a rated capacity of 20 gallons. It uses a four cycle aluminum block engine. The machine has 21 oz engine oil capacity and 12 oz of compressor pump oil. The machine uses a time tested reliable type H tank which makes it one of the longest performing and most reliable machines that you can buy.