you can check the link http://www.engine-parts.cn/en/showroom/engine_bearing/ to check more detailed information about the main bearing.
The following info was removed from the page because it lacked citation. Information on the Ford V8 and Chevrolet 6-cylinder was incorporated from other wikipedia articles. I'm putting the removed content here in case someone wants to find citations and add this to the page.
- All [MOST]single- and V-twin-cylinder engines have at least two main bearings, one at each end.
- Parallel (inline) twin engines as used in motorcycles may have two, three, or four main bearings. Broadly speaking, older British twins had two main bearings. Japanese twins typically have four.
- Most modern four-cylinder petrol [engines have five main bearings, though three were once often used.]and [S]some inline six engines have [used] three main bearings, [such as some old Hudson engines,]the third in the middle. However, [all current design] four-cylinder inline diesel engines usually have five main bearings, due to the heavier loads imposed on the crankshaft.
- Almost all current production inline six-cylinder engines have seven main bearings. Older inline sixes often had either three or four main bearings.
- All modern V8 engines have five main bearings, with one crank pin between each pair of adjacent main bearings. Old designs, such as the Ford flathead V-8, produced from 1932 through 1953, often had three mains.
- Most straight-5 engines have six main bearings, to help counter the essential imbalance of this design.