Aluminum: Pistons, bearings, cases (heads & blocks).
Chromium: Rings, a trace element in steel.
Iron: Cylinders, rotating shafts, the valve train, and any steel part sharing the oil.
Copper: Brass or bronze parts, copper bushings, bearings, oil coolers, also an additive in some gasoline engine oils.
Lead: Bearings.
Tin: Bearings, bronze parts, piston coatings.
Molybdenum: Anti-wear additive, some types of rings.
Nickel: Trace element in steel, platings on some cylinder types.
Manganese: Trace element, additive in gasoline.
Silver: Trace element, some types of bearings.
Titanium: Trace wear metal, additive in some brands of oil.
Potassium: Antifreeze, additive in some oil types.
Boron: Detergent/dispersant additive, antifreeze inhibitors.
Silicon: Airborne dirt, sealers, gaskets, sand-casted parts, spray lubricants, antifreeze inhibitor.
Sodium: Antifreeze, additive in some gasoline engine oils.
Calcium: Detergent/dispersant additive.
Magnesium: Detergent/dispersant additive.
Phosphorus: Anti-wear additive.
Zinc: Anti-wear additive.
Barium: Detergent/dispersant ad