Oil Mixing and Viscosity

[Nomad Willy]

Re rslifkin’s post,

If 30-40 oil was not good for cars it would say on the bottle “not recommended for older vehicles”. Do you think for a minute with our court system and all the hungry lawyers out there that they could do w/o the warning?

If we had “dry” engines at start up of course the’yd get ruined pronto, but we don’t. I’m saying obviously there’s enough residual oil to protect the bearings.
See the picture of my 40 year old Nissan w 303,000 miles on it. This is the car that I used 40 wt oil in for about 4 yrs and have switched to hi milage 10-30. No bearing noises other than while cold in the valve train. If there was insufficient lubrication over even one year the engine would be toast.

 

[Bacchus]

Re rslifkin’s post,

If 30-40 oil was not good for cars it would say on the bottle “not recommended for older vehicles”. Do you think for a minute with our court system and all the hungry lawyers out there that they could do w/o the warning?

Eric
While I usually agree w you I have to take exception here.
Any oil labels I've seen list the API codes it satisfies along with some marketing hype. I have never seen a warning about where not to use it. The only warnings / cautions are health related... against constant contact can be harmful.
I have not seen cautions about any API categories that it does not satisfy / should not be used. I would think that would be risky if they list 1 or more did they list EVERY use it doesn't satisfy and if not doesn't that open them up if one claims you cautioned me against certain uses and mine wasn't listed... must be OK?
I'm open to other thoughts but would like to see a label that supports your claim.
I havent seen do not use in diesels for Sparky classifications nor against gas engines for diesel oils.., just the classifications they comply with.
Don

 

[rslifkin]

It's up to the car manufacturer, not the oil manufacturer to specify what oil is suitable. The oil manufacturer just states what viscosity the oil is and what standards it meets. Realistically, most engines have a pretty wide range of oils that'll keep them happy.

For the dry start thing, they're not totally dry, but with just the leftover film, things do see slightly more wear at startup (and while cold before everything is warm and expanded to normal shape and getting good oil splash to any splash lubed parts). It's not a large amount of wear or anything, but the wear in the first 5 seconds of cranking and startup is definitely more than what you'd get from 5 seconds of running once warm.

 

[Nomad Willy]

Bacchus,
I’ saying because it DOSN’T have a warning it dosn’t need it. It dosn’t because the residual is enough to prevent damaged parts. So many cars go so very far w/o more than residual oil it says more oil is not necessary.
Perhaps I stated it wrong.

rslifkin,
Yes it’s probably about how much residual oil. There may be “slightly more wear” at start up but even if there is a slight bit it’s too small to prevent cars from going 200-300,000 miles.
So there’s no reason to consider it or otherwise worry about it. My Nissan starts almost instantly .. it’s amazing. It’s very short cranking time may/probably had an effect. IF THERE IS ANY WEAR at start up.

 

[FF]

Since the engine is not under load till it is started the lack of an oil film may not cause that much wear, but the shape of the engine internally is different from when the engine temperature has normalized .

Modern engines do not use round pistons , they are oval , happily a computer remembers hundreds of measurements , so the selection is precise , unlike "the old days" with hand built .

For folks that worry , they could follow what ships do, heat the engine coolant,fuel and lube oil and pre oil the engine .

Cruse ships that run on generators switch on non operating units that sit with heat coming from a running generator , and expect full power instantly , with no extra wear.
Car engines shut down for a traffic light would still be warm on restart.

Many modern cars use synthetic oil which has great sheer strength , so the main & rod bearings should not be bothered by multiple warm starts.

A diesel in a boat that only runs infrequently might be helped with a block heater that would help the engine regain it operating shape quicker.

But at 200-300 annual operating hours , most are good for decades anyway.

 

[Bacchus]

Eric
After re- reading I guess I misinterpreted the post.
My apologies. Oil in boats, cars, motorhomes is one of those never ending discussions I find interesting.
Don

 

[rslifkin]

Block heaters definitely do reduce startup wear. But as Eric pointed out, in most cases, if you're using a reasonable oil and have something resembling a normal usage pattern, startup wear isn't a significant concern.

 

[sunchaser]

See the picture of my 40 year old Nissan w 303,000 miles on it. This is the car that I used 40 wt oil in for about 4 yrs and have switched to hi milage 10-30. No bearing noises other than while cold in the valve train. If there was insufficient lubrication over even one year the engine would be toast.

Congrats Eric. Maximas from that period were amongst Nissan's best effort. The engines were stellar and have "carried through" the decades much like the small block Chevy's.

 

[Nomad Willy]

Ff,
I worked in a powerhouse w an 8cyl 1440hp diesel. For start up the lube oil was circulated throughout the _engine after being heated. Oil was in a 300 gal sump tank deep in the floor. Oil drained/dripped down into the crankcase and directly back into the sump tank. When the engine started (compressed air) you couldn’t hear when it actually was running on it’s own. While running and generating power it went from 300kw to 1400kw instantly w/o loosing over 2rpm. Aided by a 90” five ton flywheel.

Don,
Our boat engines live in a relatively warm environment rarely or never experiencing freezing temps. Preheated if you will. And startup wear is just for conversation.

Dunchaser,
I’m pleasantly surprised. I had an 82 Maxima 4dr 6cyl diesel w 5 speed. WAY too noisy. And oddly the worst noise was at light loads. I loved to see a hill coming as I could stick my foot in it, make some power and run quietly …. relatively speaking.
The Maxima dosn’t score well in the “Long Term Quality Index at (dashboard light)” but our experience seems to indicate otherwise. Thanks for posting.

 

[diver dave]

my '85 535i did 345k miles on dino 20w50 oil its entire life. no top or bottom end work on major stuff, although I did put in a new oil pump at low 300k something.
thats thick oil! I found out what happens when in the NC mountains in winter too.

 

[Nomad Willy]

Diver,
I used 20w50 in most everything not long ago. Including motorcycles.
Viscosity is golden … I agree.

For a trawler (typical) nowadays 15-40 w a quart of 50w 60w (or whatever it takes) to produce 20w50 may be a good thing. Valvoline makes a 60w racing oil that if combined w 4+ times as much basic product such as 15w40 the racing additives wouldn’t be anything but good in small quantities.

The 15w40 is for OTR trucks that start and operate often in sub zero temps. Our trawlers don’t ever (basically) experience such temps. Could easily operate with a higher viscosity product. And probably be better for it. Just say’in.
One should see if it conforms to manual spec’s tho.

 

[KnotYet]

Diver,
I used 20w50 in most everything not long ago. Including motorcycles.
Viscosity is golden … I agree.

For a trawler (typical) nowadays 15-40 w a quart of 50w 60w (or whatever it takes) to produce 20w50 may be a good thing. Valvoline makes a 60w racing oil that if combined w 4+ times as much basic product such as 20w40 the racing additives wouldn’t be anything but good.

The 15w40 is for OTR trucks that start and operate often in sub zero temps. Our trawlers don’t ever (basically) experience such temps. Could easily operate with a higher viscosity product. And probably be better for it. Just say’in.

A typical modern trawler engine will have one or more turbochargers.
My experience is that full or part-synthetic oil does the best job in a turbo.

Your viscosity fixation doesn't reflect the significant technological advances in
both engine and oil manufacturing that has taken place in the last 50 or so years.

The only engines that would need 50 or 60 weight oil added to them are maybe
older air-cooled Harleys and the like or engines so worn as to need rebuilding.
Even racers will avoid heavy weight oil in search of every last horsepower since
increasing viscosity increases drag; quite significantly at higher rpms.

In short, the off-the-shelf oils of today are able to provide all the lubrication needed
for nearly every engine in use today as has been demonstrated over and over again.
Supplementing oil with the goal of increasing viscosity is a solution in search of a problem.

 

[Nomad Willy]

KnotYet,
Do modern engines found in a trawler like Volvos and Cummins engine specify lube oils in lighter grades like cars or are they about the same as 20 yrs ago?

In the old days (about 60’s) we’d all be running 30w if you exclude multi-vis. And before that we were. Now in a trawler we don’t need lighter oil for starting since our engines never get cold as in stay above 40 degrees. So IMO a MV oil is not needed. We’re just using car and truck oil and the viscosities normally available.

I’m not try’in to go back to the 50’s. Where applicable I use the oils including the recommended viscosities .. like 5w30. But in cars and trucks there’s a real need for MV oils. In trawlers no such need. I never ran anything but 30w in my Willard. No reason to go higher or lower. Now that I think of it a 20w40 oil could have been more optimal. But the straight 30w was perfect enough. By the way it’s engine was made in 06 but no 5w30 or such was recommended. One could make a case for 10w30 since most of these Mitsubishi engines were installed on small frontend loaders and such.

It’s only smart to use technology … when it’s smart. If it’s not one is just being stupid to be or to view ones self as modern.

“ Even racers will avoid heavy weight oil in search of every last horsepower since ”
The only racing oil I know about is very high vis 2 stroke syn. or 60w oil for car racing. In both those two applications higher vis oils are used.

But yes a lot of new tech has come our way in 50 yrs. But using 0w16 oil in a 1990 car is not informed or smart.

By the way rpm is about one minute. There’s no such thing as rpm’s.

I keep forgetting about turbochargers. But it all should be in the owners manual.

KnotYet wrote;
“A typical modern trawler engine will have one or more turbochargers”.

I think;
A typical trawler will have Ford NA Lehman engines.

 

[Bugaboo]

What changes in oil as it gets "better" or at least newer is mostly the detergent level. All containers are marked with oil detergent style.

There are on line tutorials on the difference between CD ,compression engine , D rated oil and say SD , spark engine D rated oil.(damn little)

Thin oil might help cold starting and mileage , but for long life a single wt. oil still seems to be the champ.

All ways use 30 weight Delo in all my diesel engines current car spect for 5/20 mileage oil

 

[Bugaboo]

A typical modern trawler engine will have one or more turbochargers.
My experience is that full or part-synthetic oil does the best job in a turbo.

Your viscosity fixation doesn't reflect the significant technological advances in
both engine and oil manufacturing that has taken place in the last 50 or so years.

The only engines that would need 50 or 60 weight oil added to them are maybe
older air-cooled Harleys and the like or engines so worn as to need rebuilding.
Even racers will avoid heavy weight oil in search of every last horsepower since
increasing viscosity increases drag; quite significantly at higher rpms.

In short, the off-the-shelf oils of today are able to provide all the lubrication needed
for nearly every engine in use today as has been demonstrated over and over again.
Supplementing oil with the goal of increasing viscosity is a solution in search of a problem.

 

[NCheaven]

Always interesting

Engine oil is always an interesting discussion!

I find that reading real research to be especially interesting, too, especially from independent sources. Not long ago a bunch of oils were tested in the same types of engines and compared, "The Volvo T-13 Engine Oil Oxidation test (ASTM D8048)". I won't summarize here (you're welcome!), but you can look it up easily.

Other good information is included in manufacturers' fact sheets and comparisions of their own products on product web sites. I find reading Shell Rotella's and Mobil 1/Delvac fact sheets and comparisions, especially comparing dino oils to sythetic/Dino blends and full synthetics to be highly revealing on oxidation, deposit control, corrosion, shear temperatures, and much more. Again, no summary (you're welcome, again!), but you can look it up. Some oil containers even summarize the relative performance.

Then, there are truck fleet manager tests and their choices of oils where performance and expense clearly matter, and their choices are clearly for synthetics.

Also of interest are the Americal Petrolem Institute charts of backward oil rating inclusion of older ratings and what is and is not covered by current standards, and the oil manufacturers/sellers also reference their roll up for older to newer ratings, including my engine maker's packaged oil - Volvo.

Lastly, there are the dark and stormy night forays into the papers of the Society of Tribologists and Lubrication Engineers, and their journal seems quite available and readable, Jack Daniels lubricating that my reviews of that research.

So, my choices are based on manufacturers' research and fact sheets, independent studies, fleet managers choices, and those rare dark and stormy nights in which I read Tribology research.

The bottom line is that Volvo and other oil sellers show that the ratings at the time my engine was built (2005) rolls up to the current ratings for full synthetics at Rotella, Mobil 1/Delvac and even Volvo. I stick with the original Volvo engine manual recommended, viscosity, 15W40, and buy the Rotella and Mobil 1/Delvac packaged 15W40 specifically designed and CK-4, VDS4.5 rated for "heavy duty Diesel Engines", etc.

I love reading about all of the ideas on TF on mixing oils, special operating temperatures (I'll trust my thermostats and temp gauges on that, since those are the references in the engine manual), cold dry starts and warm wet restarts, etc. But, I'll stick with the research findings of Tribologists, Engine Manufacturers, Oil Manufacturers, and fleet managers, plus oil and transmission fluid analyses from end of season changes. Sadly boring, I suppose, to be so conventional (not intended as a pun), but their amazingly consistent and uniform conclusions in favor of multi-grade synthetics and engine manufacturer's recommended viscosities are good enough for me.

 

[Bugaboo]

Engine oil is always an interesting discussion!

I find that reading real research to be especially interesting, too, especially from independent sources. Not long ago a bunch of oils were tested in the same types of engines and compared, "The Volvo T-13 Engine Oil Oxidation test (ASTM D8048)". I won't summarize here (you're welcome!), but you can look it up easily.

Other good information is included in manufacturers' fact sheets and comparisions of their own products on product web sites. I find reading Shell Rotella's and Mobil 1/Delvac fact sheets and comparisions, especially comparing dino oils to sythetic/Dino blends and full synthetics to be highly revealing on oxidation, deposit control, corrosion, shear temperatures, and much more. Again, no summary (you're welcome, again!), but you can look it up. Some oil containers even summarize the relative performance.

Then, there are truck fleet manager tests and their choices of oils where performance and expense clearly matter, and their choices are clearly for synthetics.

Also of interest are the Americal Petrolem Institute charts of backward oil rating inclusion of older ratings and what is and is not covered by current standards, and the oil manufacturers/sellers also reference their roll up for older to newer ratings, including my engine maker's packaged oil - Volvo.

Lastly, there are the dark and stormy night forays into the papers of the Society of Tribologists and Lubrication Engineers, and their journal seems quite available and readable, Jack Daniels lubricating that my reviews of that research.

So, my choices are based on manufacturers' research and fact sheets, independent studies, fleet managers choices, and those rare dark and stormy nights in which I read Tribology research.

The bottom line is that Volvo and other oil sellers show that the ratings at the time my engine was built (2005) rolls up to the current ratings for full synthetics at Rotella, Mobil 1/Delvac and even Volvo. I stick with the original Volvo engine manual recommended, viscosity, 15W40, and buy the Rotella and Mobil 1/Delvac packaged 15W40 specifically designed and CK-4, VDS4.5 rated for "heavy duty Diesel Engines", etc.

I love reading about all of the ideas on TF on mixing oils, special operating temperatures (I'll trust my thermostats and temp gauges on that, since those are the references in the engine manual), cold dry starts and warm wet restarts, etc. But, I'll stick with the research findings of Tribologists, Engine Manufacturers, Oil Manufacturers, and fleet managers, plus oil and transmission fluid analyses from end of season changes. Sadly boring, I suppose, to be so conventional (not intended as a pun), but their amazingly consistent and uniform conclusions in favor of multi-grade synthetics and engine manufacturer's recommended viscosities are good enough for me.

OK sounds good to me on a sidenote I had to replace my cooling system complete junk .Converting to keel cool dry exhaust .I pretty much decided to remove the oil cooler don’t think it’s needed keep an eye out on oil temperature and i will see .all your research how critical is oil temperature I know it plays a role in cooling the engine i understand it handles heat quite well until the flashpoint

 

[rslifkin]

OK sounds good to me on a sidenote I had to replace my cooling system complete junk .Converting to keel cool dry exhaust .I pretty much decided to remove the oil cooler don’t think it’s needed keep an eye out on oil temperature and i will see .all your research how critical is oil temperature I know it plays a role in cooling the engine i understand it handles heat quite well until the flashpoint

Oil temperature isn't just limited by the oil itself. There's a point where the engine bearings are too hot. And some engines use the oil for piston cooling too. So the max safe temperature is well below the flash point of the oil and varies between engines.

As far as the cooler, you probably can get away without it, especially if you're never working the engine hard. Just monitor the temperature and figure out reinstalling a cooler if it becomes necessary.

 

[TowLou]

I'm speaking of the gas trucks, the ones on the 1980s S-10 frame with the aluminum body that you see everywhere. There are about 140K of them in service.

They are not "stop/start" but they are moved and shut off and started many times each day.

Hopefully a better, longer lasting starter is in the newer vehicles

Depends on the years... most of those LLV's have the old gm 2.5L or 2.2L in the latter years. I believe the first number of the ID number on the truck determines the year ex. starting with a 4 is a 94 and that was a 2.5L. All of those motors blew no matter the year so frequently weather the timing chain or heads the postal service would just authroize a new rebuilt block from Jasper to toss in, besides the flywheel cracking or trans blowing up or the fuel relay that rusts up right under the hood in the path of rain water draining. Many common problems with them..... source I used to work on and tow those LLV's daily at another job. Their PM system was by months not time or miles then and probably still is and just 5w-30 I believe was the oil in there. And yes all of those LLV's on s-10 frames.

 

[Nomad Willy]

HaHa the oil cooler;

Does anybody remember I usta suggest the possibility of temperature control via removal or bypassing the oil cooler. This being a possible solution to over powered trawlers running as low as 25% engine load. Coolant and oil running well below desirable temps. Some reported coolant temps as low as 140 degrees.

The chronic problems mentioned on the LLV’s above aren’t surprising given the on/off start/stop operating cycles. Ideally an engine would be run in continuous conditions such as engine load and speed, temps and specifications of all fluids … and all else. But regarding the engine load I’m not sure no variation is best. And of course it dosn’t matter because no such constant running will be adopted by anyone. But HaHa recreational trawlers frequently run very close to constant conditions being slow and inclined to go long distances. Hours and hours of nearly constant running. But after the long hours and distances much much longer hours, weeks and even months of sitting .. not moving at all. If it wasn’t for that many trawlers would last close to forever.

Re the engines in Tow Lou’s post above the 5w30 oil it was probably spec'ed by GM and bearing clearances and other variables were all like ducks in a row. All according to the master .. GM.

And I agree w NCheaven … to do as the manual says … even though I talk about deviation.
Time alters the needs for new operating specifications for engines. Sometimes oil viscosity specs were changed w no change to engines. One could use a lighter oil in northern latitudes (especially in winter) or a heavier oil in southern climes. One jump up or down only.
But pilots of airplanes and boats alike are blessed or plagued with high levels of conservative thinking. Play by the rules types. So I’m not surprised to disagree at times here on the forum. And now that I’ve started using 10w30 in my 87 car (that spec’d it) Instead of 30w I’m with’in specs on all my engines. Only running recommended grades.

 

[rslifkin]

HaHa the oil cooler;

Does anybody remember I usta suggest the possibility of temperature control via removal or bypassing the oil cooler. This being a possible solution to over powered trawlers running as low as 25% engine load. Coolant and oil running well below desirable temps. Some reported coolant temps as low as 140 degrees.

I've been giving some serious thought to adding thermostats to the oil coolers on my engines. They're full time flow and in the raw water loop, so while they're sized for good cooling under heavy loads up on plane, the oil runs pretty cold at slow cruise (1300 RPM with the throttles just barely cracked). Depending on sea water temperature, we're talking 155 - 165*. Getting that up to 190* or so would be good (and the resulting thinner oil might save a hair of fuel too). At least the gassers have no issue keeping the coolant warm under light load.

 

[Nomad Willy]

Good thoughts all rslifkin,
As I recall Sunchaser came up w a good reason to not taking out the oil cooler … probably having to do w the transmission.
But yes I’d be wanting to get those temps up on the gas engine w the low loads. It’s great that gas engines are fine otherwise w the low loads.
I don’t think the 190 degree thermostat will affect oil temp or viscosity much at all.

 

[rslifkin]

Good thoughts all rslifkin,
As I recall Sunchaser came up w a good reason to not taking out the oil cooler … probably having to do w the transmission.
But yes I’d be wanting to get those temps up on the gas engine w the low loads. It’s great that gas engines are fine otherwise w the low loads.
I don’t think the 190 degree thermostat will affect oil temp or viscosity much at all.

I don't expect it'll affect oil temps running on plane, but the warmer oil at low speeds will also be thinner under those conditions, which should be a slight efficiency benefit.

I'm going to swap the coolant thermostats from 160° to 170° at some point as well (have the parts, just need to install them). They run 170° - 180° on plane anyway (depending on seawater temp), so it won't change much. But it'll get the temps up from 165° to 175° at low speed, so better temps under light load and smaller temp swings (I expect to see 175° - 180° on plane after the change). And maybe as low as 170* at low speed in really cold water (currently it'll get down to just on the high side of the 160° mark at slow cruise in 45° water).

 

[Bugaboo]

#1 engine oil temp 212* to 260* can handle more #2 transmission oil 175* to 225 above this very bad #3 lighter weight oil better at removing heat due to increased flow ,higher pressure less flow , less pressure more flow #4 gauges needed to maintain these temperatures , oil in oil pan , transmission oil in sump , exhaust temperature as close to engine as possible #5 install or remove cooler’s as needed

 

[Nomad Willy]

Bug,
I don’t think the pressure effects the flow enough for conversation. Fluids are not compressible so w a gear pump high vis low vis all pump the same velocity and volume.

rslifkin,
I’ve never used a thermostat rated anything but 190.

 

[rslifkin]

The oil pumps are constant volume until you build enough pressure to open the relief valve and dump some oil back to the pan.

 

[Nomad Willy]

The oil pumps are constant volume until you build enough pressure to open the relief valve and dump some oil back to the pan.

OK so it depends on where the relief valve is.
Ok is it pump, relief valve bearings or pump, bearings relief valve?
The latter …….?

 

[Bugaboo]

#1 viscosity increases ,flow rate’s decrease ,friction increase’s. #2 further fluid from pump lower flow rate #3 viscosity is the measure of resistance of fluid flow #4 how Significant in an engine they go through a lot trouble engineering oils 5/20 ect #5 pump 101 There’s a reason hydraulic fluid is a light oil whether it’s worth a discussion or not

 

[Nomad Willy]

A positive disp pump such as a gear-on-gear pump displaces a given volume of fluid every revolution. Since fluids are not compressible the volume cannot vary.

So how is velocity or volume going to change? Obviously the relief valve varies velocity, volume and pressure. But how is the relief valve and oil galleries configured?

Consider a gear on gear pump attached to a tube of some length w a “pressure relief valve” at the end. On the tube end I view it as a hole to the side of the tube followed by a piston (bit less dia than the ID of the tube) whereas a spring pushes the piston past the hole thus shutting off the passage. But as soon as the pump is turned on the piston moves out opening part (or all) of the hole. Then as you tap off holes and tubes in-between the PR valve and the pump we can vary the pressure and thus the volume of oil flowing out all the tubes.
Is that it?

 

[rslifkin]

The pressure relief valve is typically right at the pump. With the recommended weight of oil and everything up to temp, it'll only open at higher rpm. But with cold oil, it can be as extreme as being partly open at idle.