Bentley Rolls-Royce Engine Big End Bearing Set RE15121SA

Are you rebuilding the straight-six engine in your classic Bentley or Rolls-Royce? Part number RE15121SA is the correct −0.020" undersize big end bearing set for all post-war six-cylinder Crewe-built models — covering the Rolls-Royce Silver Wraith, Silver Dawn, Silver Cloud I and Bentley MkVI, R Type and S1, from 1946 to 1959.

This is a complete set of 12 connecting rod shells — sufficient for all six cylinders — and is the correct bearing size for engines where the crankshaft has been reground by 0.020 inches to restore a clean, smooth journal surface. Using the correct undersize bearing is critical during an engine rebuild — fitting standard-size bearings on a reground crankshaft will result in excessive clearance, low oil pressure and rapid bearing failure.

The three big end bearing sizes available for this straight-six engine are:

• RE3236SA — Standard size
• RH2100 — −0.010" undersize
• RE15121SA — −0.020" undersize (this listing)

This bearing set is manufactured by a major supplier of high-end engine components and is made exclusively for the Prestige Parts range. It cross-references as RE15121SA-X in the Prestige Parts catalogue.

What are big end bearings? Big end bearings — also known as connecting rod bearings or rod shells — sit between the connecting rod and the crankshaft journal. They allow the crankshaft to rotate freely while transmitting the force from each piston. They are subject to enormous stress during normal engine operation and are one of the first components to show wear when oil changes are neglected or oil pressure is low. A failing big end bearing typically produces a characteristic heavy knocking sound from the engine — often called "big end knock" — which worsens under load.

When to use this bearing set: This −0.020" undersize set is required when your crankshaft journals have been measured and found to be worn beyond standard tolerances and the crankshaft has been reground by 0.020" by a machine shop to restore a true, smooth surface. Always measure crankshaft journal diameter before selecting a bearing size. Consult a specialist mechanic or engine rebuilder if you are unsure which undersize is required for your engine.

Fitment — straight-six engine (4.25 litre, 4.5 litre and 4.9 litre): Rolls-Royce Silver Wraith — 1946 to 1959, Rolls-Royce Silver Dawn — 1949 to 1955, Rolls-Royce Silver Cloud I — 1955 to 1959, Bentley MkVI — 1946 to 1952, Bentley R Type — 1952 to 1955, Bentley S1 — 1955 to 1959.

Call our classic Rolls-Royce and Bentley specialists at +1 845 595 9822 seven days a week. In stock and ships fast from our New York warehouse.