Why using the correct oil in your Polaris engine is crucial.

Polaris Prostar engine bearing clearances typically range from 0.0010 to 0.0030 inches, with a target of approximately 0.0020 inches for both main and connecting rod bearings. Proper clearance is critical for oil pressure, at Oregon Precision Powersports we aim for 0.0015 - 0.0020 inches to prevent oil breakdown. 

The general rule of thumb for crankshaft bearing clearance is 0.001" for every 1" of journal diameter. Choosing the correct oil weight depends on balancing this clearance with engine operating temperature and load to maintain a stable oil film. 

Oil Weight vs. Clearance Recommendations

Clearance dictates the viscosity required to protect the engine; generally, larger clearances require thicker oil to maintain adequate oil pressure and film thickness.  

Bearing Clearance Range 

Recommended Oil Weight (Approx.)

Notes

0.0010" – 0.0015"

0W-10 or 0W-20

Typical for modern OEM/tight tolerance engines.

0.0015" – 0.0020"

5W-20 or light 5W-50

Balanced "tight" engine setup for performance. ***Oregon Precision's Standard***

0.0020" – 0.0025"

5W-30 or 10W-30

Standard "traditional" performance/street build range.

0.0025" – 0.0030"

10W-40 or 15W-40

Used in "loose" engines or those with higher operating temps.

0.0030" and above

20W-50

High-load racing applications or worn engines requiring thick film.


 We receive a lot of questions and concerns from customers about using a 10w in their machines.  We state absolutely not.  Your Polaris Prostar engine is built to use a specific weight of oil.  In order or maintain proper lubrication only us a 5w-50 oil

Why We Choose Maxima

When we build engines, we don't rely on marketing claims; we rely on data. After building 100’s of engines and testing a wide variety of lubricants, the pattern is clear: Maxima oils offer superior resistance to heat and fuel contamination.

In our engine teardowns, those utilizing Maxima consistently demonstrate significantly less bearing wear compared to those running other brands. When it comes to protecting high-performance engines against the specific demands of SxS life, the results speak for themselves.