How to find the right Automotive Performance Engine Connecting Rod Bearings AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Automotive Performance Engine Connecting Rod Bearings
- Measured oil clearance
- Measure with a bore gauge and micrometer. A common starting point is roughly 0.00075 to 0.001 inch of clearance per inch of journal diameter, adjusted for oil viscosity and use Clearance controls oil film and pressure. Plastigage alone is too coarse for a performance build.
- Size matched to the crank grind
- Choose standard or the exact undersize the crank was ground to, and check whether you need standard or extra clearance (the X or HX versions) The wrong undersize gives zero or excessive clearance.
- Construction for the load
- Use tri-metal performance bearings, such as Clevite H-series, King XP or ACL Race, for high load, boost or nitrous Performance bearings resist fatigue and embedment far better than standard bi-metal replacement bearings.
- Fillet radius clearance
- Use narrowed or chamfered bearings when the crank has large journal fillet radii Bearing edges that ride on the fillet cause rapid failure.
- Oil hole orientation
- Install the shell with the oil hole or groove in the correct rod or cap half, as the bearing maker specifies A misplaced shell can starve the rod of oil.
Brands that matter
- King: XP performance tri-metal bearings, with coated versions.
- Clevite (MAHLE): H-series performance bearings, with HX extra-clearance versions.
- ACL: Race series bearings, common on import and boosted builds.
- Federal-Mogul / Sealed Power: Standard rebuild bearings for stock-type engines.
What to avoid
- Mixing bearing halves from different brands or series
- Setting clearance with plastigage only on a race or boosted engine
- Using standard bearings on a crank with large fillets
Questions
What does the X in a bearing part number mean?
On Clevite and King it usually means an extra-clearance version, typically about 0.001 inch more, used for looser race tolerances.