Hitchcocks Forum

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.

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.

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.

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

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 !!!