another oil question?????

maxwell99

Well-known Member
On no, not another oil question:
For Hokie: you seem to be up on the oil questions.

I used 10w40 oil plus 1qt of Lucas oil stabilizer in
my old tractor, but when plowing, about the hardest
work it ever does,

When at idle and normal operating temperature, the
oil pressure gauge would be on the low end.

I changed to 15w40 shell rotella oil, the oil
pressure appears to hold a higher pressure.

Is that in my head or is there some reason for the
higher pressure. I understand that oil has a good
additive package.

Should I still run a qt of Lucas oil stabilizer in
the oil?

Thanks for any input.

I change the oil each spring to drain out dirt and
condensation.
 
(quoted from post at 11:16:39 10/17/14) On no, not another oil question:
For Hokie: you seem to be up on the oil questions.

I used 10w40 oil plus 1qt of Lucas oil stabilizer in
my old tractor, but when plowing, about the hardest
work it ever does,

When at idle and normal operating temperature, the
oil pressure gauge would be on the low end.

I changed to 15w40 shell rotella oil, the oil
pressure appears to hold a higher pressure.

Is that in my head or is there some reason for the
higher pressure. I understand that oil has a good
additive package.

Should I still run a qt of Lucas oil stabilizer in
the oil?

Thanks for any input.

I change the oil each spring to drain out dirt and
condensation.

OK - you asked for it ;-) I would be surprised if the gauge pressure was noticeably different but perhaps a small difference at startup. Bear with me as I explain.


Both oils are grade SAE 40. For all practical purposes the difference in viscosity of a 10W40 and a 15W40 when it is just starting to warm up (50C/120F) inside an engine is zero. The 15W40 will be a bit "heavier" at temperatures below that but again the differences are quite small until you down near freezing. That is what the 10W versus 15W in the grade label is telling you. The graph below shows how Rotella T5 in those two grades actually compare all the way from freezing up to well over boiling. At full operational engine temperature (100C/212F) they are IDENTICAL.

Now that I have your head spinning I'll try to answer the questions:

As far as I am concerned the Lucas and all similar products are a waste of money. The oil is plenty "stable" right out of the jug. If you want increased viscosity just get a heavier grade oil,

Why do you even care about engine oil pressure? Contrary to popular belief higher gauge pressure doesn't equate to better journal bearing protection. It does however provide better upper end lubrication via the various spray orifices in an engine. On an overhead valve and/or camshaft engine there is LOTS of that going on and you need good oil pressure to keep the upper end supply and spray going strong.. An N-series doesn't have any of that so it is more tolerant of lower pumping pressures. Anything over 15 PSI is probably enough to keep the bearings filled and a decent cylinder wall spray going in the flathead. If the pressure goes much lower the bearings may stay filled but the cylinder wall spray is going to look a lot like an old man's dribble ;-)

In terms of engine protection a 10W40 and a 15W40 are indistinguishable once the engine is warmed up. At cold startup the oil film inside the bearings has not been formed and will not form until the oil fills bearings. Until then the journals are running in DIRECT contact with the bearings. On a nice summer day there is little if any difference in the time it takes for the oil to fill the bearings but at temps near freezing a 10W40 will get there a bit faster than a 15W40. While that difference is relatively small that metal to metal cold startup wear is what is really hard on an engine and over the life of the engine will be noticeable, I am sure you have heard that "most engine wear occurs on startup" and that is what they are talking about. I want to scream everytime I hear someone here say something like " I only have to wait 5 seconds for the oil to warm up enough to get oil pressure". Inside a journal bearing that is an eternity. And that is why the oil industry has pushed so hard on improving oil pumping viscosity at temps below freezing. The hot end is and always has been easy. The cold end is far tougher and it has required a LOT of engineering to get to today's levels of performance. Unfortunately as consumers and end users a lot of our thinking is still mired in what we learned or thought we learned 50+ years ago....

In summary - in a hot engine there is no practical difference in the two grades but the 10W40 will provide better wear protection on cold start at temps below freezing. Use whichever one lets you sleep at night.

Now aren't you sorry you asked ;-)

TOH

T5-40grades.jpg
 
Not sorry I ask at all, that was a good explanation,

not sure I understood all of it, but end results
both oils will protect my old tractor engine.

I may continue to use the shell rotella 15w40 oil, I
rarely start the tractor on a cold day.

I use the rotella in my dodge diesel truck, fewer
oils to buy.

Again, thanks for the explanation.
 
Today Oil is Oil is Oil. Hyped upped sales pitches are nothing but a gimmick to make and take your money.Cost of the flavors is what the advertising dollars will bare on its sales. You can put any SAE detergent oil in your car, truck or tractor it will do its job. The 3000 mile oil change is the best example of the game oil brands play on the public, its a joke dont fall for it. I go 6ooo to 7500 on every vehicle I have, all are over 100K and one is 217K. I change oil in spring and summer only because I live in a 4 season climate where heat and cold dictate 10-30 10-40. You only need about 7-lbs of oil in a N for it to do its job. I have a 2N that I got in 77 it has only seen 30 weight NON-Detergent oil all its life. I worked it summer and winter like a rented mule- plowed, blade snow, bush hogged, roto tilled and much more. It has no oil leaks, it burps a little blue smoke on start up but no smoke after start up. Remember this these Ns were designed before detergent oil was even used or obtainable by most of the population. Detergent oil was made popular after the big one (WWII) So you can use Wal-Mart,oil NAPA, Big A, O'Reilly's Shell Rotella whatever you want it will all work. LB Master of the Obvious.
 
when i got my case vac i thought it was wore out looking at the OP gauge... till i read the manual and found out that 10-15 psi was the MAX :)
 
(quoted from post at 18:30:49 10/17/14) when i got my case vac i thought it was wore out looking at the OP gauge... till i read the manual and found out that 10-15 psi was the MAX :)

You know they even made engines, including some really big ones, that didn't have an oil pressure gauge OR an oil pump. :shock:

TOH
 
at the club i belong to, we have a big oil field engine, single cyl, but has an air charge cyl on the side ( antique supercharger :) )

piston bore is like a 5g bucket.

it uses trip oilers, screw grease cupsa nd an oil splash cup/bath

no pressure oiling at all..
 
TOH,

You seem to always have the answers to our oil questions, and I look for these post because every time I read one I feel like I have a little better understanding of how it all works.

Question: Is this what you do professionally? Does it relate to your work or did you just decide one day that you wanted to know all about how oil works. Just curious, and thanks for the information.
 
(quoted from post at 20:22:47 10/17/14) TOH,

You seem to always have the answers to our oil questions, and I look for these post because every time I read one I feel like I have a little better understanding of how it all works.

Question: Is this what you do professionally? Does it relate to your work or did you just decide one day that you wanted to know all about how oil works. Just curious, and thanks for the information.

The latter - I am an "oil amateur" ;-)

For 40 years I made my professional living as a software engineer - network and operating systems in particular. I am also an inveterate gear head and have been playing mechanic since I was about 14.

About 10 years ago the discussions going down on this forum got me interested in the engineering basics of "engine oil". I have a decent background in physics and chemistry and I am the sort of guy that wants to know HOW things work. Anything and everything. To use JMOR's analogy I don't really care what time it is I want to know how that damn clock works ;-)

If you have an interest in a technical issue and a decent engineering background you can learn things online today that 15 years ago you would have had to go to engineering school to learn. You can also find a lot of good sounding miss-information so you need to bring a reliable BS meter to WWW class with you ;-) Hopefully my BS meter hasn't led me astray.....

TOH
 

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