Movement Motor
When you start the motor, how does the oil pressure get up?
In most modern cars, is it the movement of the crankshaft? There's no oil pump in most cars right?
Oh sorry. I never heard of an oil pump going bad tho. Fuel and water, never oil. They must be reliable since they're drenched in oil...DOH!
Thanks Jeff, you're a true professor of mechanics, cheers!
the guy is trying to learn here. get your snippets right! the only stupid question is the one not asked.
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to answer your question,
they all develop pressure by design. within the pump and, in that all the passages journals and races have clearances such that they provide lubrication with back pressure.
oil pressure helps ensure components float in their journals/ races/bearings. so they don't actually touch when turning. many incorporate a spring loaded return check valve in the pan as well to help ensure positive back pressure as the oil, upon returning to the pan, has to overcome spring tension.
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all internal combustion motors have an oil pump. not necessarily all vehicles as there are electrics.
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pumps do fail. commonly, they can get worn to a bypass condition and not provide enough flow or pressure.
usually caused by running a motor when the required amount oil in the block is not met or if the oil pickup screen is clogged. in some engines, those with check valves in the pan, the pump can be compromised by simply leaving the oil fill cap off and driving. makes a big mess in the bay.
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most old motors had them in the oil pan. and were mostly driven by a shaft from under the distributor that led to the top of the pump in the pan. some home built hypo motors could sheer shafts on cold oil starts. this method is still used to day on at least all chain driven timing gear blocks.
newer ones may have them behind the front engine plate that surrounds the crank and are driven off the timing belt.
so in the end, all internal combustion motors (in land locked vehicles) have a pump, incorporate some sort of splash lubrication, and rely on gravity to return the oil to the pan.
i did not mention all the forms of lubrication out there. just the ones that are most common to our beloved auto's.
class dismissed!
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FYI,
back in the day, most motors if not all, did incorporate "splash" lubrication methods in the crank area. now out of date machining techniques, materials, and design dictated it.
but, splash methods did not go away and are still incorporated in many valve/rocker assemblies and all timing chains to this day!
being upside down, like in a plane, amongst other things, requires direct oil injection/passages to all bearings/races/journals and a dry sump system.
look at NASCAR for an example. while they don't go upside down (well not on purpose), they do fly around the track at 190mph+. which forces all the oil in the pan to move to one side while in a turn. pumps will cavitate as a result. so they need to be capable.
cheers!
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