Oil thread - quick question regarding 5w20 / 0w20 oils

[erik_w]

Sorry to start an oil thread but I have a niggling question I would like your input on.

Has anyone here tried using very thin oils in their engines? I mean 10w30 and below, I am especially interested to know about the 5w20 and 0w20 weight oils?

All the opinions seem to tell you not to do this, but I want to know if you have tried it?

My reason for asking is that since engine oils get better and better with advancing technology and therefore a modern 0w20 oil should IN THEORY be better ON ALL counts compared to a DINOsaur like the mineral 20w50 (a favourite for "classic" engines).

[mtiberio]

Omg... Lifter/cam wear

[Noguzznoglory]

Be careful to get the recommended API rating. Usually the newest (SM,SN?) supersede the previous rating. Not the case if your motor manufacturer  recommends SG due to lack of zinc compounds in the newer oils.

[Stevex]

I made the mistake of trying to run my LM2 on 10w/40 after renovating it. Luckily no damage was done but the warning sign was occasional oil light flickering at idle. I now use Valvoline VR1 20w/50 Racing (mineral) Oil, which actually isnt a 'race' oil but denotes it's properties...'high zinc / phosphorus providing extreme wear protection, including flat tappet applications'.
I'd definitely use whatever oil MG recommend for the bike you've got.

[Zoom Zoom]

My subaru calls for 0W-20.  Use what has been recommend by the manufacturer

ZZ

[Two Checks]

The problem with using thin oils in older engines is they aren't designed for thin oils. The reason thin oils work in car engines is clearances are tighter. Thick oils won't flow properly. The lack of "cushion" the oil provides will cause damage.
Use what the engineers say.

[Kev m]

My reason for asking is that since engine oils get better and better with advancing technology and therefore a modern 0w20 oil should IN THEORY be better ON ALL counts compared to a DINOsaur like the mineral 20w50 (a favourite for "classic" engines).

Your premise is faulty and makes the ASSumption (drink ) that just because something is newer that it is necessarily better and not just different.

It also ASSumes (drink  ) that a given brand of 20/50 or 10/60 hasn't been reformulated over its lifespan.

And maybe MOST importantly, you ignore that manufacturers spec an oil weight or range of oil weights to match desired operating parameters of their motors and at the end of the day I don't recall Guzzi EVER specing for a 20W.

A 0-20 ONLY provides the viscosity of a 20 weight.

A 20-50 provides the viscosity of a 50 weight.

So no I haven't tried it because I've never felt compelled to try an oil that is literally half or a third of the spec'd viscosity.

[stephenm]

The factory recommended weight xxW50, for example, is based on the engine maintaining oil pressure at maximum rpm when at operating temperature and at the expected highest temperature in normal use. Using a lower viscosity oil such as xxW20 may mean that oil pressure will be less than spec under the previously nominated conditions. The consequence for the engine if this happens will be accelerated wear. While oil specifications have improved over recent decades, the specified oil weight is determined during factory testing. Whether the oil used is common as muck or the best available is not the issue here. The oil weight is chosen by the factory to ensure correct lubrication under the expected conditions of use, with a margin of safety added.

Stephen

[BRIO]

It's not out of the question that a 0w20 could substitute a 5w20. The operating weight is still 20 at temperature. As others have pointed out the additive package may or may not be different. However, if the rating exceeds the manufacturer specifications the result would be reduced startup wear in theory. You shouldn't substitute for a different operating weight as the film strength of a 20 weight oil in an engine designed for 50 weight probably won't be sufficient. Additionally, the larger the spread the more additives are used to achieve that operating range. A group three oil (Dino) at 10w50 will be using a more pour point additives than a 20w50 oil. This means that the range will shrink as the oil ages and it will become both thicker at startup and thinner at operating temperature. Typically PAO based motor oils use no Viscosity Index additives yet pass the multi-grade viscosity requirements as a straight weight. This makes them ideal under a greater temperature range. One advantage of not having to employ viscosity improving additives is having a more pure undiluted lubricant.


PS: The majority of "synthetics" on the shelves today are not. This includes almost everyone's favorite Mobile one.

[Mike Tashjian]

The lowering first number in the oil rating is in part due to increased pressure to raise gas mileage. The lower number will reduce operating friction until the engine warms up. After the engine warms the oil must still protect the engine. The high side number is the rating at that temperature.  There is no way a 20 weight oil will act like a 40, 50, or 60 weight oil.  And then the new oils have reduced amounts of certain additives to reduce the contamination of the catalytic converter.  Stick to the oil recommended to minimize engine wear and maximize engine life.  Mike   

[Caffeineo]

Bob is the oil guy......for all things oil related. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm
They even have a motorcycle specific forum.

[Randown]

If you want to deviate from the mfr specified oil weight on an a/c motor you can safely do so depending on your oil temperature.

For example, using a 0W20 in an engine that specifies 20W50 WOULD be the better choice if you're operating it in a low ambient temperature AND the oil temperature never rises above its corresponding viscosity that is equal to the RECOMMENDED viscosity you'd normally see on a warm/hot day.

Generally, you can go lower on the "W" number no problem, no matter what the expected operating temps are. So, if you have an old motor that 20W50 was spec'd for you can use 10W50 or 0W50 no problem without looking at oil temps.

If you want to use a 10W40 in the winter it's a fairly safe bet but knowing your operating oil temps that you typically see between summer & winter then verifying using a vis chart the XXW40 won't thin beyond what your XXW50 does during summer temps would make it more a certainty.

[Randown]

Sorry to start an oil thread but I have a niggling question I would like your input on.

Has anyone here tried using very thin oils in their engines? I mean 10w30 and below, I am especially interested to know about the 5w20 and 0w20 weight oils?

All the opinions seem to tell you not to do this, but I want to know if you have tried it?

My reason for asking is that since engine oils get better and better with advancing technology and therefore a modern 0w20 oil should IN THEORY be better ON ALL counts compared to a DINOsaur like the mineral 20w50 (a favourite for "classic" engines).

Asking if anyone tried it is looking for misdirection. Especially in a motor with a dry clutch & separate lube for the gearbox - you're as likely to get a comment that it "runs great" or "picked up 3 hp on the dyno" but that doesn't tell the whole story.

[oldbike54]

 Seems for once we are all in agreement on this one  Use the manufacturer's recommended weight .

 Dusty

[cruzziguzzi]

Seems for once we are all in agreement on this one  Use the manufacturer's recommended weight .

 Dusty

I thought it was a joke being played on me to have 0w40 as the recommended oil for my Mercedes...

0wanything?

Does that really exist?

Put a real crimp in my: Rotella in EVERYTHING, life plan!

I'm a huge believer in manufacturer recommendations these days. Conventional wisdom no longer applies and there are simply too many things going on that I don't know about and too many internal dependancies that slip through the cracks. NPI...

Todd.

[lucky phil]

I thought it was a joke being played on me to have 0w40 as the recommended oil for my Mercedes...

0wanything?

Does that really exist?

Put a real crimp in my: Rotella in EVERYTHING, life plan!

I'm a huge believer in manufacturer recommendations these days. Conventional wisdom no longer applies and there are simply too many things going on that I don't know about and too many internal dependancies that slip through the cracks. NPI...

Todd.

I run Mobil 0w-40 in everything I own that doesn't have a wet clutch. So 4 out of 5 bikes including the V11 and 4 cars.
The upper viscosity you use depends entirely on what the temp range your bike will operate in. Every operating manual I have seen gives a list of generally 4 or 5 different viscosity oils depending on the Ambient temps expected.
Personally the exception for me is the later Guzzi 8 valve engines and their requirement for 60 weight oil. Sometimes even the designers just don't understand oils.
Don't worry too much about the XXw number just go for the lowest number you can get. Its only relevant for cold starts and when the engine isn't up to operating temp and that's when you want the lowest viscosity you can get anyway because as we all know a zero weight oil at room temp is still more viscous than a 40 weight at engine operating temp.
BTW this info is for full synthetic oils.
Ciao

[Nic in Western NYS]

I run Mobil 0w-40 in everything I own that doesn't have a wet clutch. So 4 out of 5 bikes including the V11 and 4 cars.
The upper viscosity you use depends entirely on what the temp range your bike will operate in. Every operating manual I have seen gives a list of generally 4 or 5 different viscosity oils depending on the Ambient temps expected.
Personally the exception for me is the later Guzzi 8 valve engines and their requirement for 60 weight oil. Sometimes even the designers just don't understand oils.
Don't worry too much about the XXw number just go for the lowest number you can get. Its only relevant for cold starts and when the engine isn't up to operating temp and that's when you want the lowest viscosity you can get anyway because as we all know a zero weight oil at room temp is still more viscous than a 40 weight at engine operating temp.
BTW this info is for full synthetic oils.
Ciao

I don't think I've ever participated in an oil thread but since it's winter here goes - What is the rationale for the XXw number not being as low as is available?  Flow is improved but isn't there a wear issue regarding cold starts that would argue that lower isn't necessarily better?  You could have oil flowing but not have the proper viscosity to protect the surface before reaching operating temperature, no?  PLEASE correct my limited understanding of this issue oh wiser ones!

[cruzziguzzi]

I run Mobil 0w-40 in everything I own that doesn't have a wet clutch. So 4 out of 5 bikes including the V11 and 4 cars.
The upper viscosity you use depends entirely on what the temp range your bike will operate in. Every operating manual I have seen gives a list of generally 4 or 5 different viscosity oils depending on the Ambient temps expected.
Personally the exception for me is the later Guzzi 8 valve engines and their requirement for 60 weight oil. Sometimes even the designers just don't understand oils.
Don't worry too much about the XXw number just go for the lowest number you can get. Its only relevant for cold starts and when the engine isn't up to operating temp and that's when you want the lowest viscosity you can get anyway because as we all know a zero weight oil at room temp is still more viscous than a 40 weight at engine operating temp.
BTW this info is for full synthetic oils.
Ciao

I'm interested to know that you're so pleased with that particular set of numbers. I'm still invested in Rotella due to the International Harvesters which seem to come to me like I'm their own Lourdes.

But if I can cross 0w40 with other vehicles, I'll buy that in in bulk as well. I do use it in the synth form as you note and will never vary in my AMG as I intend to keep that one to the bitter end - if it ends up in other vehicles, so much the better.

I remember the first time I read it after the warranty and consequential butt-smootching relationship at Mercedes ended:
0w40?... naught w 40... aught w 40... nil, nula, zip, nada.... Hey, ain't that 40 weight?!?
Of course, no, but still, I figured for just a sec that it was another fast-one being pulled on me.

Todd.

[erik_w]

Thanks for the replies!

If I understand correctly, when you make a multigrade Dino oil you start out with the lower number and then add viscosity improvers to achieve the higher number, so for example a 20w50 oil is actually 20 oil with viscosity improvers added to make it a 50 oil at operating temp. These improvers wear out so after a while your oil turns into 20w40, 20w30 and in the end 20w20.

With synthetics it is the opposite, it is the higher number that is the base oil, so a 20w50 is a 50 oil with additives to make it thinner at room temp. Synthetics also do not wear out and therefore will not change their viscosity over time like a Dino oil.

So yes, I also understand that if you are dealing with synthetics (not Dino) oils then you want the lowest possible number in front, to avoid cold start lubrication problems. So a 5w50 is always preferable to 20w50 and so on.

[stephenm]

 >>Flow is improved but isn't there a wear issue regarding cold starts that would argue that lower isn't necessarily better?<<

Even 0W- oils are too viscous when cold. The key to understanding this is knowing that the first number xW- and the second number
-xx are different scales and refer to different things. In reality, if the two numbers referred to viscosity, you would see a 20W-50 referred to as something like a 350W-50, indicating that at cold start, the oil is very thick. Even a 0W-50 would be referred to as something like a 200W-50 using the same scales.

In broad terms, if you could get a stable 00000W-XX oil, your engine would start easily in cold weather, have great oil flow straight away and wear would be minimised.

Stephen

[Zoom Zoom]

"I'm a huge believer in manufacturer recommendations these days. Conventional wisdom no longer applies and there are simply too many things going on that I don't know about and too many internal dependancies that slip through the cracks. NPI...

Todd."

Truer words were never spoken. With tolerances being much tighter in modern engines, and many autos using variable valve timing, getting oil to the proper places in the engine are critical. How that engine performs under certain parameters is part of the design along with the specified fluids.

John Henry

[Nic in Western NYS]

>>Flow is improved but isn't there a wear issue regarding cold starts that would argue that lower isn't necessarily better?<<

Even 0W- oils are too viscous when cold. The key to understanding this is knowing that the first number xW- and the second number
-xx are different scales and refer to different things. In reality, if the two numbers referred to viscosity, you would see a 20W-50 referred to as something like a 350W-50, indicating that at cold start, the oil is very thick. Even a 0W-50 would be referred to as something like a 200W-50 using the same scales.

In broad terms, if you could get a stable 00000W-XX oil, your engine would start easily in cold weather, have great oil flow straight away and wear would be minimised.

Stephen

Thank you Stephen, very helpful and clear.  I follow manufacturers' recommendations but want to understand enough to know what is ok in a pinch and also because it's cool stuff.

[Zoom Zoom]

A search will yield many explanations and details. I found this on a quick search:

http://www.upmpg.com/tech_articles/motoroil_viscosity/

John Henry

[Randown]

Thanks for the replies!

If I understand correctly, when you make a multigrade Dino oil you start out with the lower number and then add viscosity improvers to achieve the higher number, so for example a 20w50 oil is actually 20 oil with viscosity improvers added to make it a 50 oil at operating temp. These improvers wear out so after a while your oil turns into 20w40, 20w30 and in the end 20w20.

With synthetics it is the opposite, it is the higher number that is the base oil, so a 20w50 is a 50 oil with additives to make it thinner at room temp. Synthetics also do not wear out and therefore will not change their viscosity over time like a Dino oil.

So yes, I also understand that if you are dealing with synthetics (not Dino) oils then you want the lowest possible number in front, to avoid cold start lubrication problems. So a 5w50 is always preferable to 20w50 and so on.

The fact is synthetics SHEAR & THIN in motorcycle engines just like mineral oil does. There's probably hundreds of UOA's that show this over at Bob's paid for by those in search of the holy grail.

Mineral oil (unlikely to contain any dinosaurs) can be VERY GOOD oil depending on the brand & application, in some ways BETTER than synthetics.

Typically BETTER in dealing with condensation / moisture that never happens in a Guzzi motor, & keeping the additive package in suspension.

Where it falls short for SOME air cooled motors is with it's limited viscosity range, eg you won't find a 10W60 in a mineral oil. You'll find narrower ranges like 5W30, 10W40 & 20W50. That can be just fine if you live in a mild climate or just don't ride when it gets cold. Expect a lower flash point temperature but still pretty high 400F vs 490F for a synthetic comes to mind.

If you see a 10W60 spec'd for a motor you can sort of guess the manufacturer had trouble controlling oil temperature OR decided to forgo expensive hardware & let the oil get HOT. Some think of a 10W60 as a thick oil but for those Guzzi motors that are spec'd to use it; at operating temperature on a hot day it's likely to be THINNER than a cheap 10W40 mineral oil running inside a a liquid cooled bike.

[lucky phil]

With synthetics it is the opposite, it is the higher number that is the base oil, so a 20w50 is a 50 oil with additives to make it thinner at room temp. Synthetics also do not wear out and therefore will not change their viscosity over time like a Dino oil.

Actually No. A full synth oil of 0W-40 is a Zero weight oil at 40degc and remains the equivilant viscosity of a 40 weight oil at 100 deg c due simply to the inherent nature of its molecular structure. Remember its a man made molecule and doesn't follow the same exact  path as a mineral based oil. It still thins as it reaches operating temp but less so than a mineral oil which to cover the same viscosity range needs to start as a 20 weight and have Viscosity improvers added to it.
This is a major advantage of synthetics in that they don't need a VI package and therefore don't shear down over time to anywhere near  the extent of a mineral oil.
They will also go to far lower temps where a mineral oil turns to wax.
Of course there are also many other advantages on top of these.
Ciao     

[cruzziguzzi]

Actually No. A full synth oil of 0W-40 is a Zero weight oil at...

Wait, what... it's weightless?

Me? I run straight no-weight in my Heemi!

My head hurts.


Todd.

[jacksonracingcomau]

I made the mistake of trying to run my LM2 on 10w/40 after renovating it. Luckily no damage was done but the warning sign was occasional oil light flickering at idle. I now use Valvoline VR1 20w/50 Racing (mineral) Oil, which actually isnt a 'race' oil but denotes it's properties...'high zinc / phosphorus providing extreme wear protection, including flat tappet applications'.
I'd definitely use whatever oil MG recommend for the bike you've got.

I think this warrants discussion
If it happened to an engine I built, I wouldn't contemplate thicker oil, better, maybe, but something very wrong here.
Funny thing I learnt something cos of this
I really believed my 78 LM was specced 10/40 from beginning, have pretty much always kept to that (synth from about 82)
Looked up every book I have, was apparently 10/50, same for all BB pushrod till 1100Sp, that was 5/50, markets may differ, none of my books mention temps

Other than that I have nothing to offer but would use 0/40 or 5/50 and be scared if oil light flickered, not of the oil but of impending shrapnel.

[lucky phil]

Wait, what... it's weightless?

Me? I run straight no-weight in my Heemi!

My head hurts.


Todd.

No its NOMINALLY a zero weight oil. You can go into the minus weight oil and the future will probably see this. Its only a figure based on the centistokes measured at a fixed temperature.
Ciao

[lucky phil]

I think this warrants discussion
If it happened to an engine I built, I wouldn't contemplate thicker oil, better, maybe, but something very wrong here.
Funny thing I learnt something cos of this
I really believed my 78 LM was specced 10/40 from beginning, have pretty much always kept to that (synth from about 82)
Looked up every book I have, was apparently 10/50, same for all BB pushrod till 1100Sp, that was 5/50, markets may differ, none of my books mention temps

Other than that I have nothing to offer but would use 0/40 or 5/50 and be scared if oil light flickered, not of the oil but of impending shrapnel.

If your LM2 was putting on the oil light at idle with a 10-40 oil then it wasn't an issue with the oil its an issue with the engine or oil system but probably not a critical one.
The LOP light flickering at idle isn't a major issue anyway. Every time I have seen this if you increase the idle a couple of hundred rpm it goes out. Just because the light is flickering doesn't mean you have zero oil pressure it means you have reached the switch threshold ( around 2.5psi on a Ducati which uses the same switch) that's more than adequate pressure at idle.
Ciao

[jacksonracingcomau]

If your LM2 was putting on the oil light at idle with a 10-40 oil then it wasn't an issue with the oil its an issue with the engine or oil system but probably not a critical one.
The LOP light flickering at idle isn't a major issue anyway. Every time I have seen this if you increase the idle a couple of hundred rpm it goes out. Just because the light is flickering doesn't mean you have zero oil pressure it means you have reached the switch threshold ( around 2.5psi on a Ducati which uses the same switch) that's more than adequate pressure at idle.
Ciao

Not arguing but in 40 odd Guzzi years I've never seen this happen, would still scare me now.
Only ref I have is 10psi for every 1K engine revs, I've only ever bumped it for higher revs.

I'd have to fit gauge to see what was going on, just peace of mind, sounds like something well worn to me, oil light doesn't come on till well stopped in my exp.
If yours flickers, maybe is acceptable,
But on rebuilt engine ?