Just Drained The Mobil 1 - Page 5

Trapper L · 01-29-2004, 07:12 PM

Well the SCrew gets Chevron Supreme 5w-20. I have never had a wear metal in the double digit range. This is due to the oil and driving habits. My stock Bronco gets Delo 400 and my hotrod Mark VII gets Chevron Supreme 10w-30 as does my girls Cougar. My 74 F-100 with a not even close to stock 391 gets Delo 400. I don't run synthetics and nobody at work runs them either. If you have need for an oil that will see temperature extremes, prolonged idling, or pulling a heavy load, you might be a candidate for synthetics. For the average driver there are NO benefits unless it gives you a warm fuzzy. Synthetics will not make your engine last longer or go more miles than dino for the average driver. It does have some desirable properties like better shear stabilty, uses fewer viscosity improvers, and has better pump rates but the AVERAGE driver doesn't need these properties over todays dino oils.

JetForeman, you may think I have the perfect job but trust me, it's not glamorous at all. The Delvac 1 will equal or exceed Amsoils Diesel oil any day. If you have a CAT dealer nearby, see if you can buy their synthetic in bulk. It is the same as Delvac 1 with a trace marker for analysis. Of the synthetics that use PAO basestocks, Delvac 1 is on the top of the list.

JetTech · 01-29-2004, 07:44 PM

Thanks Trapper, so for my driving habits of which include several runs to max. rpm shift every day and the Atlanta hot weather in the summer, the Chevron Supreme 10W-30 should keep everything smooth and long lasting?

Coolhand · 01-30-2004, 07:31 PM

Yo Trapper and Jet -

I'm a dumb-*** when it comes to engines beyond the stuff every man should know (

), but I'm an aero engineer and have been a bicycle mechanic most of my life. I'm just starting to see the light w/regard to engine oil via this thread - my question is, what is shear stability in engine oils and how does it play into oil performance?

Thanks,
Justin

pluckyew · 01-30-2004, 07:48 PM

what's the top three oils to use?
i've been using Castro GCX 10w-50.

Coolhand · 01-30-2004, 07:51 PM

What Pluck said... I was just gonna ask that...

Deepwater · 01-30-2004, 08:04 PM

Quote:

Originally Posted by pluckyew

what's the top three oils to use?
i've been using Castro GCX 10w-50.

Pluck,

You are running 50 weight oil! I now understand why your mileage figures are down. I have always been told that flow rates of oil are more important for cooling and cleaning of the motor than viscosity. Fifty weight oil is awful heavy, especially in colder temps. (but I'm no engineer...) Just my two cents.

JetTech · 01-30-2004, 08:07 PM

Quote:

Originally Posted by Coolhand

Yo Trapper and Jet -

I'm a dumb-*** when it comes to engines beyond the stuff every man should know (

), but I'm an aero engineer and have been a bicycle mechanic most of my life. I'm just starting to see the light w/regard to engine oil via this thread - my question is, what is shear stability in engine oils and how does it play into oil performance?

Thanks,
Justin

I can give you my understanding of it and I'm sure Trapper can give you the technical side of it. The shear stability of an oil determines its ability to stay in a viscosity range over the course of its use. An example of shearing is the oil film not being able to maintain an oil barrier between the bearings and journals. A lot of the oils I've read used oil samples on will drop in viscosity after 3 to 5k miles which is an indication it's shearing. You may start with a 5W-30 but after 3k miles it comes back in the SUS range as a 5W-20. This isn't particularly good for the bearings or any other part of the engine that experiences high loads. In used oil samples the SUS viscosity will tend to be out of ranger (lower) than the limits and your lead and iron ppm (parts per million) will be higher indicating a lot of wear is taking place.

From the oil samples I've seen, Chevron Supreme, Chevron Delo, Texaco/Havoline, and Pennzoil Purebase are some of the most shear stable non-synthetic oils out there.

Deepwater · 01-30-2004, 08:18 PM

From all the articles that I've read, it seems to me that synthetics are the better choice. Cold start up flow rates especially below zero degrees where regular oil doesn't want to flow very good. Synthetics seem to get up to the moving parts a lot quicker thus, less wear at cold start up. Also, I have read that a lot of synthetics are polarized molecules (meaning they bond or stick to bearings and all metal surfaces.) So, after cool down of engine supposedly, some fragments of oil remain. Also, they seem to exhibit a tolerance for extreme heat (400 degrees plus). BUT, what i've been reading from members of this site, they seem to think otherwise. I am no engineer but I am a little confused at this point myself on this issue. More info is needed.

Coolhand · 01-30-2004, 08:19 PM

Thanks Jet,

So the next question is, where does one get their oil tested? I use the typical 15 minute places and also occasionally change my oil myself, time allowing. Is there some standard place that you guys take oil samples for testing?

Thanks again,
J

JetTech · 01-30-2004, 08:22 PM

Quote:

Originally Posted by Deepwater

From all the articles that I've read, it seems to me that synthetics are the better choice. Cold start up flow rates especially below zero degrees where regular oil doesn't want to flow very good. Synthetics seem to get up to the moving parts a lot quicker thus, less wear at cold start up. Also, I have read that a lot of synthetics are polarized molecules (meaning they bond or stick to bearings and all metal surfaces.) So, after cool down of engine supposedly, some fragments of oil remain. Also, they seem to exhibit a tolerance for extreme heat (400 degrees plus). BUT, what i've been reading from members of this site, they seem to think otherwise. I am no engineer but I am a little confused at this point myself on this issue. More info is needed.

I can tell you from a used oil analysis that I did, on my wifes Mercedes, that some synthetics will shear too. I used Mobil 1 0W-40 in it and after 5k miles it had sheared down to a 30 weight oil. My wear numbers were still good but the oil sheared down. Not a good thing if I was going to run it longer. By the way, the oils I listed above usually come back with very high flashpoints over 400'F.

JetTech · 01-30-2004, 08:25 PM

Quote:

Originally Posted by Coolhand

Thanks Jet,

So the next question is, where does one get their oil tested? I use the typical 15 minute places and also occasionally change my oil myself, time allowing. Is there some standard place that you guys take oil samples for testing?

Thanks again,
J

Yes, go here http://www.blackstone-labs.com/ and they will send you a free sample kit. I think it's $20 for the test when you send it in and it usually takes about 7 days to get the results.

Coolhand · 01-30-2004, 08:28 PM

Quote:

Originally Posted by JetForeman

Yes, go here http://www.blackstone-labs.com/ and they will send you a free sample kit. I think it's $20 for the test when you send it in and it usually takes about 7 days to get the results.

Thank you sir!

J

JetTech · 01-30-2004, 08:32 PM

Quote:

Originally Posted by pluckyew

what's the top three oils to use?
i've been using Castro GCX 10w-50.

Darn Pluck, that's some seriously heavy oil. You have that in your Titan? You may be experiencing overkill with the heavy weight and marginal parasitic losses. Have you tried any of the 5W-40's yet? They seem to be a good "one oil suits all conditions"

Deepwater · 01-30-2004, 08:35 PM

Quote:

Originally Posted by JetForeman

I can tell you from a used oil analysis that I did, on my wifes Mercedes, that some synthetics will shear too. I used Mobil 1 0W-40 in it and after 5k miles it had sheared down to a 30 weight oil. My wear numbers were still good but the oil sheared down. Not a good thing if I was going to run it longer. By the way, the oils I listed above usually come back with very high flashpoints over 400'F.

I have been running Mobil 1 exclusively in my trucks. Question, Do you think that the shearing down of the oil weight that you are talking about has anything to do with "blow by" of fuel over time mixed into the oil? What I have experienced, is that any miles after 3,500, the oil tends to thin and you start to burn oil do to it going past the rings. I have experienced no oil burning before 3,500 miles, therefore, I always change my oil between 3,000 and 3,500 miles. It may cost a little more but what do a few beers cost at a bar.... Give me your opinion on this. Thanks.

JetTech · 01-30-2004, 08:39 PM

It sounds like you are a very good candidate for an oil sample. Fuel will usually cause the oil to thin out like your talking about and will drastically lower the flashpoint, thus causing the oil to burn off by lowering its volatility. If your experiencing this it sounds like you may have a leaky injector or your O2 sensor is bad causing the engine to run very rich.