Why do Subarus spin bearings?

Why Subarus Spin Bearings
Subaru engines are known to be at a higher risk of spinning bearings due to several factors related to the design and maintenance of the engines. The physical size of the bearings used in Subaru’s EJ-series engines is relatively small, leaving less margin for error if the engine is suffering from detonation or oil control issues. When the oil film between the bearing surface and journal disappears, typically due to a sudden loss of oil pressure and flow, metal-to-metal contact occurs, causing scuffing, increased friction, and heat. This can lead to catastrophic damage, including the familiar knocking noise (AKA “rod knock”) and the potential need for a complete new bottom-end on the motor.
One of the contributing factors to oil pressure and lubrication problems in Subaru engines is low oil level in the oil pan due to leaks, maintenance neglect, or improper filling. Additionally, oil pump cavitation and aeration at high RPM due to pump design and restrictions can also contribute to these issues. Pinging or pre-detonation from improper tuning or running too hard in extreme, hot conditions can overload the bearings in many Subaru motors, further increasing the risk of bearing failure.
In terms of maintenance, it’s important to monitor oil levels constantly and use the correct oil weight for the driving conditions. For example, during summer track days, stepping up to a higher weight oil like 20W-50 can help prevent oil starvation in the engine. Additionally, using an aftermarket pickup, such as the KillerB pickup, can help prevent oil starvation issues caused by aggressive cornering.
In summary, the risk of spinning bearings in Subaru engines is influenced by factors such as the physical size of the bearings, oil pressure and lubrication problems, and maintenance neglect, including improper oil levels and oil weight for driving conditions. Addressing these factors through proper maintenance and, in some cases, aftermarket modifications can help mitigate the risk of bearing failure in Subaru engines.

What is a spun bearing Subaru?

Sometimes the bearing catches on the crank and starts spinning with the crankshaft, which builds an intense amount of heat that can lead to con rods snapping and blowing the entire block apart. Subarus seem to be at a higher risk of these failures due to several issues with the EJ-series engines.

Do Subarus have wheel bearing issues?

Subaru wheel bearing replacement is a common requirement especially for older Subaru models that don’t have the type 2 bearing design.

Why do motors spin bearings?

What causes a spun rod bearing in an engine? First, there are engine mechanical problems. Poor lubrication is the leading cause of most bearing failure. This could be anything from a low oil level to a defect in the oil pump and oil galleys.

What causes a Subaru to spin a bearing?

Subaru EJ motors have a common failure – in stock or modified engines, that is a spun bearing, typically it is a rod bearing. Thinking aloud, the normal cause for a spun bearing is lack of oil.

Why does my engine keep spinning bearings?

A spun bearing is usually the end result of a chain of unfortunate events. These include high operating loads, excessive heat and a loss of lubrication. Spun bearings are often blamed on a loss of oil pressure, but there can be numerous contributing factors that eventually cause the bearing to seize and spin.

Can an engine with a spun bearing be fixed?

Yes, most of the time ,but it may be necessary to do some expensive machining work on the crankshaft or engine block. You might need a new connecting rod. But sometimes the damage is bad enough that repairs aren’t practical, unless maybe the engine is extremely valuable.

Why do Subaru bearings fail?

With the Subaru EJ engines having such a small oil capacity, the oil gets saturated with combustion by products and other engine material sooner. This dirty oil wreaks havoc on bearings and causes them to wear prematurely. With the bearings already being at a disadvantage due to their size, wear also occurs sooner.

How do you stop a bearing from spinning?

Even simple measures can be reliable and economic solutions to keep bearings in place. Form-fit means that the bearings shape in itself serves as an anti-rotation feature. You can achieve this easily by changing the round outer shape of a bearing into something with an edge or any other protruding feature.

How long do wheel bearings last on a Subaru?

How long does a wheel bearing last? Wheel bearings have an average lifespan of 136,000 to 160,000 km (approximately 85,000 to 100,000 miles). This is only a rule of thumb though, the actual lifespan of a wheel bearing depends on the quality of the wheel bearing and the operating conditions.

Does a spun bearing ruin engine?

Yes, once a bearing spins oil circulation beyond bearing stops so damage starts. Typically the bearing journal has holes in it to supply oil pressure to the bearing, and if one of them turns in the housing along the crank excessive leakage drops the oil pressure overall.