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What is quality Main Rod bearing?

Main crankshaft bearings(Main Rod bearing)support crankshaft providing its rotation under inertia forces generated by the parts of the shaft and oscillating forces transmitted by the connecting rods. Main bearings are mounted in the crankcase. A main bearing consists of two parts: upper and lower.

Main Rod bearing
Main Rod bearing

The Crankshaft bearings that support the crankshaft play a critical role in handling the power the engine produces as well as engine durability. Because of this, bearing selection, fit and installation can make or break your engine build.

Every bearing manufacturer has different products for different applications, from stock to extreme performance. If you’ve had good success with a particular brand and type of bearing you might as well stick with the same bearings you’ve been using all along. On the other hand, if you’ve had some failure or fitment issues with a particular brand or type of bearing and the problems have not been due to your own machining mistakes or assembly errors, you might want to rethink the wisdom of using the same bearings in future engine builds. Switching to a different grade of bearing or a different bearing material may be the solution to your bearing problem.

Crankshaft bearings both reduce friction between the rotating part of the engine and the stationary part and support the crank. The bearing material must be extremely strong because of the stresses caused by the explosions inside the internal combustion engine. Reducing friction is accomplished in part by the fact that dissimilar metals slide against each other with less friction and wear than similar materials will.So an alloy bearing material does a much better job of keeping a steel crankshaft moving than a steel or cast iron bearing does.

Main Rod bearing Main Crankshaft Bearing
Main Crankshaft Bearing


-Main Rod bearing(Main Crankshaft Bearing)


Late model production engines are factory equipped with bi-metal aluminum bearings because these bearings contain no lead, are less expensive to manufacture than tri-metal lead-copper bearings, and can last upwards of 200,000 miles in most stock applications. Aluminum bearings also have good seizure resistance. To increase hardness, aluminum bearings contain a small amount of silicon. The higher the percentage of silicon in the alloy, the harder the bearing. Silicon also helps polish the microscopic burrs that are left on the surface of cast iron cranks after they have been ground and polished.


Crankshaft Bearing manufacturers use different aluminum alloys in their products. Alloys are formulated to optimize fatigue strength, wear resistance, seizure resistance and conformability. The aluminum alloys that bearing manufacturers use today are much better than the ones from years ago. Special, high performance alloys may contain extra tin, copper or other ingredients to increase strength for racing applications. Many bi-metal aluminum performance bearings can handle loads as high as 10,000 PSI (550 to 600 hp).


Most factory crate engines, as well as performance crate engines today, are assembled with aluminum bi-metal bearings. But it’s important to remember the bearings in these engines are intended for a certain horsepower level. If the engine is further modified and makes more power than the bearings can handle, the result may be bearing failure. Aluminum bearings typically flake and peel when loads become too great, whereas tri-metal bearings often wipe or smear when overloaded.


-Main Rod bearing(Main Crankshaft Bearing)


Quality control at every step in the manufacturing, machining and assembly process is so important. Bearing manufacturers go to great lengths to assure bearings are made to the correct size. Many performance bearings are bored rather than broached because boring produces more consistent sizes.


Manufacturers also try to match bearing shell thicknesses as closely as possible (to within .0001˝ according to some manufacturers). Yet, it’s not unusual to find brand new bearings in the box that are mismarked or the wrong size for the application they are supposed to fit. It doesn’t happen very often, but when it does it can create a real disaster if somebody doesn’t catch the mistake.


The same goes for machining crankshaft journals, main bores and rod bores. If the finished dimensions are not correct, you can’t expect the bearings to fit properly. The bearings may be too tight or too loose in the bores. That’s why rod and main bearing clearances should always be measured with a dial bore gauge, not a simple plastic gauge check.

We recommend our LandTop Main Rod bearing to you. Our generator accessories are of high quality and favorable prices. We have professional technicians to escort your machines.

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