[Healeys] Fwd: Re: Oil Cooler on 67 3000

[Robert Blair]

--- Robert Blair <rnbmail at yahoo.com> wrote:

hi listers,

they told me my email was too long, so here is the
first part - look for the second ......

> 
> Hi listers,
> 
> Some comments on oil coollers, and the some theory:
> 
> 1.  they are designed to produce a net lower temp of
> the oil circulating, and they generally achieve that
> by exposing hot oil to cooler external temps via the
> cooler core which is simply a heat exchanger with
> cool
> outside air.  the rate of loss of heat from the oil
> to
> the air is proportional to the difference in temp
> between the oil and the air. simply, hot oil loses
> heat faster than cool oil, and, cooler air extracts
> heat faster than warmer air - just physics.
> 
> 2.  the cooler oil is more viscous - true of most
> fluids, which can be loosly translated into it is
> more
> difficult to pump against a resistance [such as the
> small oilways and tight bearings etc], which can be
> loosly translated into producing a higher oil
> pressure
> being present as measured at the input side of the
> circuit. the pressure drops to zero as the oil
> completes its circuit and drips back into the sump.
> 
> 3.  a more viscous oil will generally [there are
> other
> facots of course] withstand more force between
> surfaces before breaking down and allowing the
> surfaces to physically meet and cause mechanical
> damage. eg oil vs water under your shoe on concrete.
> 
> 4.  at the same time an oil that is too viscous will
> flow more slowly, forcing the input side pressure up
> [ie cold starts], and therefore will not conduct
> away
> heat so rapidly from loaded areas such as bearings. 
> this in turn will increase the local oil temp within
> the bearing [the heat remains resident if not
> conducted away by metal and oil], lowering the local
> viscosity, and may allow a local drop in pressure
> allowing bearing damage in continuous hard use.
> 
>more soon ................... >>>>>>>>

                        Robert Blair
rnbmail at yahoo.com 
Cell: 408-221-5244

   

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