Features & Benefits of Coated Engine Bearings

Today I will cover the benefits to using coated bearings vs. uncoated. Coated bearings are not needed in all situations. There are also different types of coatings used in specific racing and performance applications.

Take a look at my tips below and you’ll be on your way to being a bearing expert! Well maybe not quite an expert yet, but you’ll gain some valuable knowledge that is sure to help you choose the right bearing for your engine.

Clevite® coated engine bearings offer thesame quality, same material, and same process as used by both major NASCAR® teams and drag racing teams. All Clevite® coated bearings start out as “H” Series racing bearings, known around the globe as the “leading race engine bearing” whenever and wherever large amounts of horsepower are made.

There is just one exception to the above statement: For the 3,000HP alcohol dragsters and the 10,000HP nitro funny cars, top fuel dragsters and top fuel drag boats, MAHLE Clevite offers a specially engineered nitro V series coated bearing to survive in these hemi-style engines.

Why use coated bearings?

  • Offer added protection against dry starts
  • Provide a barrier layer between the bearing and crankshaft when:
    • High cylinder pressure reduces oil film thickness to almost nothing
    • Detonation causes extreme cylinder pressure which, again reduces oil film thickness to almost nothing
    • Slight misalignment in caps and rods or caps and block saddles reduce bearing clearance to almost nothing
  • Make “reading bearings” easier when the engine comes in for service
  • Near frictionless bearings with increased power
  • Help protect the crankshaft from heat damage when bearing/clearance problems exist

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Uncoated bearings on left. Coated bearings on right. Notice the wiping on the uncoated bearings caused by a very minimal oil film. Observe how much better the coated bearings look from the same engine.

How to choose the right coating for your engine bearing:

You might naturally think; “I want the nitro coating since it’s so tough,” but in reality it’s designed for a specific situation and may cause bearing failure when misused. Nitro and alcohol engines have a service interval of typically a mile or less (1000 ft in a nitro dragster) and they typically have almost no oil film thickness due to the extreme firing pressure load on the bearings. The coating MAHLE Clevite uses is created specifically for this environment and does not work well in long endurance engines (5 to 100,000 miles). The coated H series bearings (CB663HNK for example) are engineered for this and are a far better choice for most racing and performance engines.

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H Series Clevite Coated Bearings

Already getting started? Check out these Engine Bearing Installation & Fitting Tips



. by Doc