Forum

[Chriscar]

Hello
What are your thoughts, experience.s
using a phosphor bronze bearing instead
of a white metal bearing for a big end
with the same oil holes.
Regards Chris.

[Bullet Whisperer]

It depends on how old you are and how much time you have left to experiment, as some white metal bushes have lasted 50 years or more.

[Tim NZ]

IF the White metal floating bush runs short of oil, the white metal will over-heat, melts and the then the big end starts to knock. You may still get home if you ride slowly...


Facing the same shortage of oil scenario: 'bronze' bush over-heats, expands, seizes, and the con-rod SNAPS. You call for Road-side assistance.


A Bronze bush is at best only a cheap get me home desperation substitute, as the bronze has a different thermal expansion to steel backed white metal. Get the ID or OD dims wrong and it will either seize rapidly or suffer premature wear as a result of oil bypassing due to lack of hydrodynamic film.


Oil viscosity is critical, as too is oil cleanliness. Dirty oil will wear out a bronze bearing faster than a white-metal version. Not advised for High speed/load applications. If it was a suitable option for a High speed crank shaft bearing, you would sort of expect manufacturers to be using it...


DONT DO IT.

[Ian Martin]

As usual the advice and engineering logic presented by Tim is spot on.

[Alan R]

Hi Guys !!
Good reply there TIM and much appreciated........If I may just expand a bit for some of the owners on here who, unlike ourselves haven't the benefit of an Engineering Apprenticeship or lifestyle ??........So, have a look at this for Hydrodynamic Film}---------- https://en.wikipedia.org/wiki/Fluid_bearing -------- (One of the few action Films NOT starring John Wayne,I think -- LoL !!).
OK, now this next one is -- I warn you --- a bit long-winded but given its' Author then its' at least worth a scroll down....Remember that the original question was directed at PHOSPHOR BRONZE for a bearing material}---------- https://www.copper.org/applications/ind ... aring.html --------
From my own personal experiences of high speed application ( Motorcycle Grass-Track engine development ) and high load application ( Heritage Steam locomotive bearing manufacture and fitting ) I would agree with Paul and Tim ie}--- Stay with what the Original Equipment manufacturers stipulate in the form of the steel shell with a white metal lining............Incidentally another "plus" in favour of white metal is that it allows small, solid particles to become embedded within its' surface and still function, something that might compromise a roller type bearing....

And don't forget those REGULAR oil and filter changes !!!