Hello, i know i saw this somewhere, but i can't find it anymore.
What oil pressures are you seeing with the melling oil pump at idle and at other RPM's
thanks
james

Stock I see ~31 after fully warmed.

At idle, after warm-up, I see about 30-35 psi; under full load (wot), I'll see 60-70 psi.

okay, i noticed this. when the car is cold, oil pressure is higher, and when it is warm it drops. is this due to the oil thinning out? i do ot think we have any temperature/oil related valves in our car?
thanks
james

We do. There is a relief valve in the oil pump controlled by a spring that manages oil pressure.

Dino,
this valve i know of, but that is a pressure regulator, it is not temperature related is it, the pressure drop from cold to hot is due to the oil thinning isn't it?
thanks
james

Engine oil thickens (increases in viscosity) as it get hot, not the other way around.

Umm, that's backwards Dino. The warmer oil is the thinner it is and the less pressure it takes to move it. Try pouring a quart of oil that's been in your garage in the middle of winter. It's thick as molasses. That will increase oil pressure until it warmes up. My 91 has the "ticking lifter" problem. When it's cold it's quiet, when it warms up it gets louder. It is normal to see *some* decrease in oil pressure from startup (cold) to running temp. IMO, of course...;)

i thought it was like this 10w-40 flows like a 10 weight oil, but does not thin more than a straight 40 weight oil would thin at a certain temperature.
lates
james

"Engine Oil and its viscosity

For satisfactory lubrication of the engine the oil should possess some functional properties of which viscosity of oil is one of the most important properties, as it brings out the oil’s capacity to lubricate. Viscosity is the measure of oil’s resistance to flow. An oil’s viscosity is identified by its SAE’s (Society for Automotive Engineer’s) number. The <b>thinner and oil, lower its number</b>, e.g. SAE 10 W. The numerical relates to viscosity at particular temperature and the alphabet ‘W’, indicates the oil’s suitability for colder temperature. With the viscosity index improver, the <b>viscosity increses at higher temperature and at lower temperature it does not increase significantly</b>, thus achieving optimum viscosity at lower and higher temperature. Such oils are called multigrade oils, for instance ‘20 W40’ shows thinness at low temperature and thickness at higher temperature."

See the rest of the article here: http://auto.indiamart.com/auto-consumables/engine-oil-its-viscosity.html

Viscosity ratings are for ambient temperature flow, not operating temperature flow.

http://www.autoeducation.com/autoshop101/oil-change.htm


Oil weight, or viscosity, refers to how thick or thin the oil is. The temperature requirements set for oil by the Society of Automotive Engineers (SAE) is 0 degrees F (low) and 210 degrees F (high).

Oils meeting the SAE's low temperature requirements have a "W" after the viscosity rating (example: 10W), and oils that meet the high ratings have no letter (example SAE 30). An oil is rated for viscosity by heating it to a specified temperature, and then allowing it to flow out of a specifically sized hole. Its viscosity rating is determined by the length of time it takes to flow out of the hole. If it flows quickly, it gets a low rating. If it flows slowly, it gets a high rating.

Engines need oil that is thin enough for cold starts, and thick enough when the engine is hot. Since oil gets thinner when heated, and thicker when cooled, most of us use what are called multi-grade, or multi-viscosity oils. These oils meet SAE specifications for the low temperature requirements of a light oil and the high temperature requirements of a heavy oil. You will hear them referred to as multi-viscosity, all-season and all-weather oils. An example is a 10W-30 which is commonly found in stores. When choosing oil, always follow the manufacturer's recommendation

Page "5"

Most petroleum oils have pour points in the range of -15 to -35 degrees F. That means that their borderline pumping temperature is, at best, around -15 degrees F and probably closer to 5 to 10 degrees F. So, if you're running a petroleum oil, don't expect to go out and start your car at 0 degrees and have it purr like a kitten. It's going to spit and sputter and kick and scream for a few minutes.

Why do you think that is? It's not getting any oil up into the engine. It's like trying to suck molasses through a tiny straw in an Alaskan January. There's literally nothing keeping the metal components in your engine from tearing each other apart. Every time you start your engine in conditions like this, your engine dies a little bit more.


Now that I've bored you to death, you can check out this link as well if you're still not convinced.

http://www.amsoil.com/testimonials/lotito.htm

i believe its my lifter thats making the ticking noise... when its cold no noise (loud)..but once its warmed up (sometimes) it will make this ticking noise.. if it gets hot outside and i have been driving it hard/alot in the heat, it will do this..most of the time it happens when i start it back up after a long drive in hot weather.. is this bad to drive like this?
Michael 99gs
Mods:
Hrc Stage 2
S-FMU
315cc injectors
Crane HI-6DI2
Greddy Type S Bov
VC-2
Road Race Catch Can
Greddy Profec B & Switch
Apexi WS Catback
Super Afc
Autometer Boost, electric fuel, Egt, Tranny Temp Gauge & Cooler, Air/Fuel Light & Digital
Tokico Adjust Struts
Eibach Pro Kit Springs
Front & Rear Upper Bar
2 piston calipers(front), powerslot rotors, r4-s pads, & rre lines
CarCraft Interior
Sound System= Bring it On

Hey Michael,

I used to think I had lifter tick until I recently changed my exhaust manifold gasket. Turns out it was just that. IT was an exhaust leak. You might want to give your exhaust manifold bolts a check. My bolts between cylinders 2 and 3 on the bottom side were particularly troublesome and prone to leaking.

We're saying the same thing here, it just doesn't sound like we're hearing each other.

That's 'cause I have my fingers stuck in my ears. :D

My oil pressure evens out at 20psi when it's warmed up and usually starts around 40-50 depending on the temperature outside. Should I be worried?

Clint
97 Eclipse GS

20psi after being warmed up?

Seems a bit low since most people tend to say they are around 30-35 at idle after being warmed up. I would probably be worried about something leaking etc... What kind of oil do you use?

10w30. I am in Texas, and when it was cooler, it didn't get quite that low, but it does make me a bit nervous.

Clint
97 Eclipse GS