What’s the Difference Between ACL Race H (Standard) and ACL Race HX Bearings, and When Should You Us

What’s the Difference Between ACL Race H (Standard) and ACL Race HX Bearings, and When Should You Use HX?

ACL Race bearings are renowned in motorsports and high-performance tuning engines for their durability and ability to withstand extreme conditions. Two of the most popular types, ACL Race H (Standard) and ACL Race HX, are specifically designed to endure the harsh demands of racing, but key differences between them can dictate which one is best suited for your engine. Understanding these differences will help you make an informed decision.

What is the ACL Race H (Standard) Bearing?

The ACL Race H bearings are designed for engines requiring tight clearances. These bearings ensure precise oil flow and temperature control, making them ideal for high-performance engines where oil pressure needs to be maintained at optimal levels.

Oil clearance: The typical oil clearance for ACL Race H bearings is 0.0254 mm (0.001 inch). This clearance provides adequate lubrication between the high-speed crankshaft and the bearing surface while preventing oil loss and pressure drops.

Application: ACL Race H bearings are ideal for engines that require tighter tolerances, where excessive oil flow is not necessary. These bearings are perfect for high-performance street cars or race engines with controlled oil requirements.

What Does the ACL Race HX Bearing Offer?

The ACL Race HX bearings are similar to the H series but offer increased oil clearance due to a slightly larger internal diameter. This allows a thicker oil film to form between the crankshaft and the bearing, which is crucial for high-temperature, high-performance engines where additional lubrication and cooling are necessary.

Increased oil clearance: The oil clearance for HX bearings can be as large as 0.0381 mm (0.0015 inch), which allows more oil to flow between the bearing and the crankshaft. This enhanced clearance improves both lubrication and heat dissipation, especially in engines running at peak performance.

Application: HX bearings are recommended for engines that experience heavy loads or have polished crankshaft journals, which require more clearance for optimal oil flow.

When Should You Choose ACL Race HX Bearings?

ACL Race HX bearings are ideal for engines that demand a thicker oil film due to high loads and increased heat. They are also useful in cases where the crankshaft journals have been polished, and a larger internal diameter is needed to maintain the necessary clearance, avoiding metal-to-metal contact.

Example: After polishing the crankshaft journals, the reduced diameter may cause standard bearings to create too tight a clearance, leading to overheating and wear. The HX bearing’s larger internal diameter maintains the proper clearance, preventing these issues and ensuring longer bearing life under extreme conditions.