Checking the oil filter for chips

[The Fabricator]

For those who wonder about the condition of their engine.

A simple job that can reveal some evidence.......

 

     

 

  

 

      

 

 

                                                                                                                      Is it steel or other iron containing material.  A magnet will tell.

                                                                                                                            Not in this case.

   

 

 

This aluminum chip appears to be a shaving that is curled up.  It may be 'swarf' from manufacturing.   I wonder how a chip of this size passed through the oil pump screen.  It may have been lurking in an oil gallery passage.

 

  

 

 

  

 

Take note that the oil filter does not filter oil all of the time.  The filter  has a by-pass valve built in to it.  This valve opens to prevent too much oil pressure pushing on the oil trying to pass through the filter element.  Too  much pressure on high viscosity oil [cold oil] can rupture the filter.  Also,  at high RPM's, the pressure can be too high, causing the filter by-pass to open. 

 

From the BMW repair manual for the R1150GS-

The by-pass valve opens at 21psi pressure differential.  At cold start up, after the oil passages have drained somewhat, the pressure  in the oil passages is 0 psi initially, this condition can exist.

The engine operating pressure is 50 to 85 psi.  The oil pressure relief valve opens at 75 psi.  The engine circulates 8 gpm at 6k rpm.  It might be possible for a 21 psi pressure differential to exist at some combination of conditions on a running engine at the upper extremes of engine speeds.

 

The oil pump is the first to suffer from the chip as it sucks up oil that has passed only through a screen first.  A worn pump will pump at reduced pressure compared to an un-worn pump.