When it comes to engine reliability and performance, bearings play a critical role, and few names carry the reputation that ACL Bearings do. Whether you're rebuilding a daily driver or pushing the limits on track, understanding the differences in bearing types and applications is key to making the right choice.
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Who are ACL Bearings?
ACL (Automotive Components Limited) is an Australian manufacturer renowned for producing high-performance engine bearings. Their Race Series bearings have become a staple in motorsport and tuning circles, trusted by builders worldwide for their durability under extreme conditions. ACL also offers standard replacement bearings, designed to meet or exceed OEM specifications for everyday use.
Standard vs Race Bearings: What’s the Difference
|
Feature |
Standard Bearings |
Race Series Bearings |
|---|---|---|
|
Material Composition |
Typically bi-metal or tri-metal |
Hardened tri-metal with copper-lead base |
|
Load Capacity |
Suitable for OEM-level loads |
Designed for high-load, high-RPM environments |
|
Clearance Options |
OEM spec |
Available in tighter or looser clearances |
|
Oil Groove Design |
Standard oiling |
Enhanced oil flow for better lubrication |
|
Use Case |
Daily driving, stock rebuilds |
Track, drag, drift, and high-performance builds |
Race Series bearings are engineered to withstand the rigours of motorsport, including higher temperatures, increased loads, and rapid RPM changes. They often feature advanced metallurgy and precision tolerances that reduce friction and improve longevity under stress.
Main Bearings vs Conrod Bearings: What’s the Role?
Understanding the difference between main bearings and conrod bearings helps clarify where each fits in your engine build:
- Main Bearings - These support the crankshaft within the engine block. They absorb the forces generated by combustion and rotation, keeping the crankshaft aligned and spinning smoothly.
- Conrod Bearings - Also known as big end bearings, these sit between the connecting rods and the crankshaft journals. They handle the reciprocating motion of the pistons and transfer combustion force to the crankshaft.
Both types are critical — but they endure different stresses. Main bearings deal with rotational stability, while conrod bearings face intense pressure from piston movement.
Oversized Bearings: When and Why?
Oversized bearings are used when the crankshaft journals or housing bores have been machined — typically during an engine rebuild or repair. Machining removes material to correct wear or damage, and oversized bearings compensate for the increased clearance.
Common Scenarios for Oversized Bearings:
- Crankshaft Grinding: If journals are worn or scored, they’re ground down and oversized bearings are fitted to restore proper oil clearance.
- Block Line Honing: When the main bearing bores are honed for alignment, oversized bearings may be needed to maintain correct fitment.
- Performance Builds: Builders may choose specific bearing sizes to fine-tune oil clearance for high-RPM reliability.
Oversized bearings are marked with designations like +0.25mm or +0.010", indicating the extra thickness to match the machined surfaces.
The Round Up:
ACL Bearings offer precision, reliability, and performance, whether you're refreshing a stock engine or chasing podiums. Understanding the nuances between bearing types and sizes ensures your build is not only powerful but dependable. If you're unsure which ACL bearing suits your application, consult your engine builder or reach out to us and our team will help wherever they can.