What synthetic oil are you using???? And HoW oFtEn YoU cHaNgE iT?

[MorningGaser]

For my 2007 Toyota Yaris, 1.5L, I use Mobil1 Filter, and Mobil1 0W-20 synthetic except during the summer, when I use Mobile1 0W-30. The car is spec'd for 5W-20 but I want less viscosity during start ups to minimize cold wear & tear on the engine. I change the oil every 5,000 miles. I believe that flow is more important to engine protection then pressure.

[trebuchet03]

Originally Posted by MorningGaser

I believe that flow is more important to engine protection then pressure.

Journal bearings don't work as bearings without pressure

[JanGeo]

Except when you use Synlube then even 5-6 psi is enough to keep the bushings lubricated . . . Miro didn't recommend that I install a mechanical oil pressure gauge because pressure would not matter when using Synlube since the lubrication is provided by the solids in the lube and not the hydralic pressure. Seems weird but it is working great so far.

[VetteOwner]

Originally Posted by trebuchet03

Journal bearings don't work as bearings without pressure

haha yup, its what goes when your oil pump dies... general rule of thumb on that is oil psi should go up 20 lbs per 1000 rpm.(least its true on 2.2L GM engines.)

[Sigifrith]

Originally Posted by VetteOwner

haha yup, its what goes when your oil pump dies... general rule of thumb on that is oil psi should go up 20 lbs per 1000 rpm.(least its true on 2.2L GM engines.)

Wouldn't this be dependent on oil temp? My 95 Chevy varies in PSI at idle at the start of a trip to the end. 62 PSI in the morning down to 25 PSI at work. But the idle also drops from 1500 to 800.

[trebuchet03]

Except when you use Synlube then even 5-6 psi is enough to keep the bushings lubricated . . . Miro didn't recommend that I install a mechanical oil pressure gauge because pressure would not matter when using Synlube since the lubrication is provided by the solids in the lube and not the hydralic pressure. Seems weird but it is working great so far.

Journal bearings are fluid bearings - there's no physical contact between components (from something like a ball and race bearing). They also rely on pressure to work as a bearing... Theoretically, you could run those bearings using high pressure water (much higher given lower viscosity) The only time there's physical contact is during oil priming and startup (no or very little pressure). So if you had high flow, low pressure - they won't be working as bearings, and instead it will just be a lubricated shaft spinning in a cylinder :/

I'm not saying that solid lubricants are not necessary - I'm just saying that given a journal bearing with a properly functioning oiling system, there should never be metal to metal contact (where you'd want/need solid lubricant).

[JanGeo]

Actually it probably relies on the oil film strength since the piston is seeing 190 psi and the piston area is far greater than the curved bearing surface so you are seeing much higher pressures on the bearing even before the spark ignites the fuel than the oil pressure is providing.

[smay665949]

I switched over to Amsoil in my 2001 Chevy Impala right after it turned over 201,000 miles for the extended oil and filter changes. The Amsoil 10W-30 Synthetic motor oil and filter are rated for 25,000-mile change intervals. I have almost 205,000 miles on the car now and the oil still looks like it was when I put it in. As an added benefit my Impala gained 2 mpg, it starts easier and is smoother running with Amsoil. Now I expect to get another 200,000 miles out of the car as long as the rest of the car doesn’t wear out before the engine.

In addition my buddy and I did a little lab test Redneck style. We took a capful of Amsoil ATF and a cap full of petroleum ATF and put them in separate drip pans. Then we took a torch and lit them on fire. The Amsoil immediately tried to move away from the flame before catching fire. We let it burn until it went out waited for it to cool and the Amsoil ATF was still liquid and slippery. The petroleum ATF lit off immediately, produced really black smoke and turned to charcoal like burning something in a frying pan. There was a little liquid left in a corner that was like stepping on gum when I ran my finger through it.

http://www.lubedealer.com/T&SMay/fea...ductsview.aspx

[VetteOwner]

Originally Posted by Sigifrith

Wouldn't this be dependent on oil temp? My 95 Chevy varies in PSI at idle at the start of a trip to the end. 62 PSI in the morning down to 25 PSI at work. But the idle also drops from 1500 to 800.

yea true, oil gets warm gets thinner.that and i dunno about you but i know on my s-10 cold starts the oil psi needle doesnt moce until itswarmed up. i think the sending unit is eithe rgetting gummed up when its cold so that could be a possibility for you too

[smay665949]

Your right it will come in handy when the tranny catches fire!

It also helps extent the life of transmissions used in towing applications that tend to run hot.