This ACL High Performance main bearing set is machined 0.25mm oversize, for a Mazda B6/BP/BP-T (1.6L/1.8L) crankshaft main journal that has been reground 0.25mm over standard. Per ACL's own fitment data it's used in the Mazda Miata, 323, MX-3, and Protege, the Mercury Capri, and the Kia Rio and Sephia. Main bearings support the crankshaft in the engine block and are matched with rod bearings to control bottom-end clearances.
Specifications:
- Type: Main Bearing Set
- Series: High Performance
- Size: 0.25mm Oversize
- Engine Fitment: Mazda B6/BP/BP-T 1.6L/1.8L
- Part Number: 5M8353H-.25
FAQ
What does "0.25mm Oversized" mean?
It means the bearing is machined 0.25mm over standard thickness, for use with a crankshaft main journal that has been reground 0.25mm undersize.
What vehicles does this main bearing set fit?
It's sized for the Mazda B6/BP/BP-T 1.6L/1.8L engine, used in the Mazda Miata, 323, MX-3, and Protege, the Mercury Capri, and the Kia Rio and Sephia.
Do I need rod bearings too?
Yes, this listing is for main bearings only. Rod bearings for the B6/BP/BP-T are sold separately.
How do I know if I need the 0.25mm oversize instead of Standard?
Your engine builder or machine shop will specify the size based on how much material was removed when the crankshaft was reground. Standard size is for a stock, unmachined crank.
