On Sunday 08 October 2006 09:30 am, Terrible Tom wrote:
> hmm - ok - this is where I admit to knowing very little about the
> properties of solids and liquids when it comes to expansion and
> contraction due to temperature. LOL
Ok, so high school chemistry class was a long time ago, but from what I
remember it works like this:
Solids, especially metals, expand and contract slightly with changes in
temperature. Not very much, but enough that you can use this to get two parts
that are machined to fit together to go together a little bit easier by
heating one with a torch and dropping the other in a bucket of icewater. If
the tollerences are machined right, once the hot part cools, it will be stuck
tightly to the cold part that has now warmed up.
Liquids boil, but otherwise don't change much. If they did, then we'd have
trouble with hydraulic systems like brakes applying themselves as the fluid
warmed up.
Gases expand and contract a lot with changes in temperature.
Then there's the whole solid/liquid/gas thing where by varying the temperature
and pressure you can convert one in to the other. And the melting and boiling
points vary with the material(s) in question as well. For example, adding
anti-freeze to water can raise its boiling point and lower its melting
(freezing) point. Adding salt to water raises its boiling point, but I don't
recall what it does to the melting point.
The cooling system shows this. You have a pressure cap set for 15psi or so.
This raises the pressure on the system as the coolent heats up and tries to
boil. With the higher pressure, the boiling point is increased, allowing the
temperature to rise even higher before the solution can boil. Eventually the
rise in temperature generates enough pressure to overcome the cap and does
allow the solution to boil, which pushes some of the mixture out in to the
puke tank and relieves the rise in pressure. The system equalizes, via the
temperature control of the thermostat and the pressure control of the cap.
Later, as the engine cools, the gas generated by the boiling coolent shrinks,
lowering the pressure of the system, and sucking the overflow coolent back
in. There would be some slight expansion and contraction of the rubber hoses,
too, but I think that's probably negligible.
> However one wishes to try and explain why theres no oil in the center of
> the filter, (and I'm open to suggestions) the fact remains that oil on
> one side and not the other is solid proof the element is clogged.
No disagreement on the filter element being clogged.
What I haven't been able to find out yet is which side of the oil pump the
filter is on. Is the pump pushing oil in to the inlet side of the filter? Or
is it pulling clean oil out of the outlet side?
I suspect that it's pulling the clean oil out, which then starves the pump if
the filter plugs up, so they put the bypass valve in to allow the pump to
suck dirty oil if it can't suck from the filter. If so, then I suspect that
the pump was simply able to empty the filter before it finally plugged
completely. The bypass valve would have kept oil flowing through the system,
but as the element clogged up, less and less of it would have been run
through the filter element.
This archive was generated by hypermail 2b29 : Wed Nov 01 2006 - 01:35:00 EST