Extreme Duty Marine Semi Synthetic 20W-50 Engine Oil

Lucas Oil Products, Inc.

Extreme Duty Marine Semi Synthetic 20W-50 Engine Oil

Lucas Extreme Duty Marine Semi Synthetic 20W-50 Engine Oil is designed for use in high performance boats requiring the ultimate protection.

Lucas Extreme Duty Marine Semi Synthetic 20W-50 Engine Oil is manufactured with the highest quality paraffinic base oils and is fortified with an exclusive additive package containing high levels of Zinc, Moly and Phosphorus that provides a tougher, thicker additive film for maximum protection even under the most sever conditions. It lowers oil temperatures, extends oil life and minimizes metal fatigue.

Lucas Marine Semi Synthetic 20W-50 improves the film strength between the cylinder  wall and piston rings and slows oil burning while improving pressure levels in worn engines. It has good cold temperature properties and stands up to high operating temperatures. This product is compatible with methanol and all racing fuels.

Key Benefits

  • Excellent for use with supercharged, turbo charged or nitrous oxide high performance engines.
  • Protects against rust and moisture during long periods of storage.
  • Safely blends and is compatible with synthetic and non-synthetic oils.
  • Dropping point 540 lbs
  • Provides rust and corrosion protection in both fresh water and salt water environments.
  • Effective Water Resistance
  • Long Lasting
  • Resist Extreme Pressure
  • Extreme Friction Reducer



  • #10654 - 1 Quart (Case of 6) - 946 mL



Product Spec Sheet Technical Data Sheet
Safety Data Sheet Safety Data Sheet

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Craig Michelson uses Lucas Heavy Duty Oil Stabilizer for 1942 M-7 Priest Sherman Tank

My name is Craig Michelson and I am the curator and vehicle maintenance coordinator for American Heritage Park in South El Monte, California. We have over 140 vehicles from World War I to present. The museum has in its inventory a 1942 M-7 Priest which is basically a Sherman tank with the top cut off and a 105mm gun installed. This particular vehicle has a nine cylinder, 975 cubic inch aircraft style radial engine.

Before starting radial engines the motor has to be hand turned to make sure the bottom cylinders do not fill with oil and cause a hydrostatic lock.

About a month ago we used Lucas Oil Stabilizer in our last oil change. This morning the mechanics turned the engine with the hand crank and noticed it started with less effort. After it started there was less smoke coming out of the engine during the warm-up. This is proof to me that your product does what it claims to do.

Craig Michelson

El Monte, California

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