Clevite MS-1266HGX Engine Crankshaft Main Bearing Set H-Series Full Groove

The Clevite MS-1266HGX is an engine crankshaft main bearing set from Clevite's H-Series performance bearing line. Main bearings support the crankshaft on a film of oil, and this set is designed for competition and high performance engines.

Key Features:

• H-Series design: The H in the part number suffix identifies the H-Series, which was developed primarily for NASCAR-type racing and is suitable for all types of competition engines.
• Full 360-degree grooving: The HG suffix indicates a main bearing with full 360-degree grooving, as opposed to the standard 180-degree upper half groove (H = 180 degrees, HG = 360 degrees).
• Extra clearance: The X in the suffix denotes .001 extra clearance, a variant offered for standard size shafts.
• Medium eccentricity and high crush: H-Series bearings have a medium level of eccentricity and high crush for secure retention.
• Enlarged chamfers: These provide greater crankshaft fillet clearance.
• No flash plating: Bearings are made without flash plating for better seating.

Application Notes:

• Use H-Series bearings with crankshafts that have oversize fillets and where engines run in the medium to high RPM range.
• They are a good choice if contact patterns from P-Series parts are too narrow. Contact patterns should ideally cover 2/3 to 3/4 of the bearing surface.
• If you are unsure which type of performance bearing to start with, H-Series is the recommended starting point.

Full grooving helps supply oil to the connecting rod bearings, which makes this set a useful option for performance builds where rod bearing oiling is a priority.