Deckwar Tapered Shims is committed to providing a tapered shim made of hard copper alloy, correctly engineered, accurately tapered that will correct engine rod and crankshaft bearing wear and bring them back into their proper clearance. Learn more about our products. Started in 1970, Deckwar Tapered Shims is a family owned and operated business based in Ojai, California. In 1939 the first hand-made Paramount Tapered Shims were installed in a six-cylinder Oldsmobile engine. Ten years later they were removed from said engine and both the bearings and the tapered shims were in good serviceable condition. Now 80 years later Deckwar Tapered Shims are still being made and used in the very same way…to shim up badly worn bearings in engines of all make and size from automobile engines, both new and old, to farm equipment, to any other engine that is worn and need shimming.