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Automotive term

Bearing wash the way i heard it that too much oil pressure some how would wash or strip off bearing material & after time cause the bearing to fail but i would think more pressure would be better could they be talking about babbit bearings the old type newer bearings are a harder material right.

Yes, that is possible, but with this “alien” term, everything is mere speculation.

This topic was discussed to death yesterday in the following thread:
http://community.cartalk.com/posts/list/2138826.page

Many of todays shell bearing inserts use babbit or lead as the primary surface…

I’m not sure ANY amount of oil pressure can “wash out” a plain bearing. Over time, perhaps a very high flow rate could erode a bearing.

You must understand, once the oil is in in the bearing, a wedge of oil forms in front of the rotating shaft and is squeezed under TREMENDOUS pressure that the bearing created itself by its design and the shafts rotation. This wedge of oil prevents the shaft from ever actually touching the bearing material except for a few moments during a cold start-up…

There are MANY examples of plain bearings that operate just fine with just a modest amount of non-pressurized oil… Most rail-road cars roll om plain bearings with nothing more than a packing of oil-soaked rags to keep 40 or 50 tons rolling along smoothly and at very low friction… The old steam locomotives had their connecting rods lubricated with a hand oiler and little oil cups on the rods…

It is pretty much accepted that in high-speed automotive engines, an oil pressure of 10 PSI per 1000 RPM is sufficient to cool and lubricate the engine. Boosting the pressure above that accomplishes nothing and wastes a lot of power.

Back in the days when a big repair shop would have the capability of “Pouring Babbit”, rebuilding connecting rods, the term “Bearing Wash” may have been used either correctly or incorrectly… Today, this term has no place in the automotive jargon…

The old babbitt bearings were a little softer than modern bearings. They tended to be made of “white metal” which was a term for several different combinations of babbitt alloys. I recall that most of the older engines that I have owned or worked on had an oil pressure of about 30-40 psi. Todays engines run a little higher oil pressure. Most oil pressure gauges max out at 100 psi but I’ve seen some as low as 40 psi. I don’t think that high pressure would cause any damage to the bearings. Oil pumps are basically constructed the same with exceptions for high volume and high pressure units.

Babbitt bearings were made of an alloy of tin and copper, lead and tin and copper and lead for the most part. Modern bearings are made of steel with a coating of bronze. Babbitt bearings usually lasted 50K on average with modern bearings going 200K or more with the proper periodic maintenance. Babbitt bearings were softer and did wear quicker. I don’t think you need to be concerned about high oil pressure destroying bearings. The real enemy of engine bearings is low or no oil pressure.