Midlife......

iTrader: (2)

Double edge sword then......

Too thin an oil will cause microwelds as surfaces touch and it's low mass-specific heat capacity will not carry away heat from combustion in the cylinders.......

Back to a compromised oil like Silkolene Pro-R or as it is now called Fuchs Titan Pro-R 15w50. ..........which I use in my car

Shaun

captain_anonymous_2003

How is a 15W-50 oil a compromise based on what I've said? Do you run this vehicle at very high temperatures a lot? Track/Race it? If you're using this mostly to drive to work and have the odd thrash this oil is far from a compromise. What you are compromising is cold protection for protection you rarely need if ever need. That's not a compromise.. that's silly.

Midlife......

iTrader: (2)

"circulus in probando"

Shaun

captain_anonymous_2003

I don't see how it's circular reasoning. Unless you're tracking that car pretty much all the time.. a 15W is not a good choice..

I don't know why people are so quick to reject this. Is it because you can't justify your choice? I have no vested interest in whatever oil you put in your car, you can run it on chip fat for all I care I won't be fixing it or paying for it. I am just trying to let people see that they can make an educated choice.

prodriverules

iTrader: (52)

so captain you'd say use a thinner oil as im quite keen to know as im just about to finish my forge build and want the right oil to safe guard the engine as best possible thanks.

captain_anonymous_2003

What are you going to be doing with the car? You want as thin as possible at cold, and you want something suitable at your typical operating conditions. If your operating conditions can vary substantially consider swapping oil for different operating conditions.

prodriverules

iTrader: (52)

Mainly normal every day usage like 4 mile trip to work with some spirited back road drives to boot so what would your recommendation be mate,ill change it out when i track day it but for normal usage id like your comments please.

KickboxingCrazy

iTrader: (15)

i think reading these interesting posts basically pick the application your going to use your car before buying your oil. i.e if your tracking it go for a oil suitable for the extra heat it brings in the engine, if your using it as a daily plod, pick a oil that will bring maximum protection from the off. as your probley find your cars oil will bearly be up too opperating temps before you get too work

MaDaSS

circulus what? LOL.
My 03 WRX has (supposedly) 45% more power than standard with the torque more than that. It has, and for a long time now been running on Silkolene Pro-R 15w50.
RCM put this in my car and recommend it. My car is currently on 97k miles.
So, even reading your very detailed knowledge on the subject, why would I ignore what one of the best Subaru specialists recommend? I mean cmon, Matt and Olly Clark know what they are on about.
Anyway, I DO have oil pressure and temp guages in my car. They are Defi's and i am not sure how accurate they are. At 6k rpm I have 6 Bar pressure. From cold that is 7 bar from start up. When warm and say at idle my pressure never goes below 3 bar.
Just driving a motorway my oil gets to 96 deg's.
I for one am not prepared to ignore what RCM recommend. They should know, they have enough experience me thinks!
These kinda threads are a can of worms. You may as well retire your keyboard now or you will get RSI before you know it!

captain_anonymous_2003

That is exactly it.

captain_anonymous_2003

When you have your oil change what did they ask you before you had it changed? Did they ask you what you do with the car? How you drive it? How many cold starts? What kind of interval you typically change in?

If they didn't ask you those, then my advice would be to get a UOA done and find out truly how your oil is performing. Why don't you do it? It's £30, if it turns out your wear is high what then? Please don't do something because someone else told you, ask them to explain their reasoning before you just take their word for it. I imagine a lot use an oil or recommend it because it's been recommended and recommended and recommended.. and no one really knows where that recommendation came from.. just that so far no cars have blown up.. (or at least to their knowledge)

Jolly Green Monster

iTrader: (4)

which part of the engine do you think is not being lubricated enough with a 15W on a cold start?

I suggested 15W50 Motul 300v competition to the OP due to the benefits I have seen from using it over thousands of miles in subaru engines high mileage standard and meduim to highly modified race engines and from stripping and rebuilding my own engines and listenning to several customers engines a day.

When I saw his car last week for a map tweak and I heard the engine start with a top end rattle than then dissappeared within a couple of seconds, my immediate question was what oil are you using.. it is too thin.. the tappets were empty when he started it..

what effect do you think thinner oil has on the film strength?

Simon

captain_anonymous_2003

I imagine when he got the car to you the engine was hot right?

Jolly Green Monster

iTrader: (4)

answer my questions and I'll answer yours..

captain_anonymous_2003

If the engine was hot then you've just defeated yourself... why would 15W-50 be better in this instance when both a 15W-50 and 0W-40 have comparable thicknesses at temperature.

0W-40
14 mm^2/s @ 100C

15W-50
17 mm^2/s @ 100C

Why on earth would your choice make a difference in this case? It wouldn't at all... The only difference your choice would make would be that your choice would perform far worse at cold starts than 0W-40. So why choose it?

Lubrication is FLOW... what you and everyone else are worried about is shear. How the properties of the oil change over time, how they thin up over time and breakdown due to thermal breakdown. This happens with all oils.. a 0W-40 might end up a 0W-30 if left for long enough, this can be countered by the use of UOAs and adjusting your service intervals. As I keep saying.. get a UOA.. don't just rely on hearsay and opinions. Get the facts!

Jolly Green Monster

iTrader: (4)

you are only considering the W of the oil... there is a lot more to it.

How am I relying on hearsay and opinions other than my own through experience with these engines..

You admit all you have done is read....errrrmmm other peoples opinions..

Simon

captain_anonymous_2003

As for film strength that we're all getting hung up on, this is an issue when you're comparing a mineral oil with a synthetic. Modern synthetics have far superior film strengths as I said before. Film strength is generally more to do with the physical construction on a mollecular level of the oil than it's thickness. A good quality fully synthetic oil will be more than adequate.

captain_anonymous_2003

Do you now admit that what you said perviously was obviously totally flawed?

NO! I am not only considering the W, and if you'd read what I have been saying you'll clearly see that. I am considering the operating conditions an engine is exposed to and making a selection based on that information. If I were driving hard, few cold starts, high temps I'd use a 10W-50 probably, and do some UOAs afterwards. If I was going to tescos.. the odd blat and getting to 100C now and again.. I'd consider a 0W-40, as it better protects my engine based on how I drive it. A 0W is always better than a 10W or a 5W. It's just making a 0W-50 isn't easy, 5W-50's are expensive and this is why! It's a better choice than 15W-50, it protects better at low temp and offers the same high temperature protection. Why not use that?

I don't doubt for a moment that you are very good at mapping cars and working with them, but if you are telling me that a 15W-50 oil is much better for a car that mostly goes to work and back and rarely gets pushed hard all year round then frankly you're nuts. That oil is designed for engines that run with conditions where temperatures are CONSISTENTLY high and also few cold starts. Not pottering to tescos and back.

I am not relying on others opinions either, I am relying on physics. This is all well documented, there are physical journals on the subject and what I was pointing you to was a detailed article that covers a lot of that work in an easy to read guide.

captain_anonymous_2003

I have gone as far as I can with this thread now, I think it's getting silly. I am not trying to be antagonistic but it just frustrates me to see this. My basic message is this.

PLEASE... do not just pick an oil because someone tells you it's a good one. Think about how you use your car and ask questions, the right questions to get a selection that suits you. Do regular UOAs and modify your selection based on those. Every engine is different, yours may well be different to someone elses but without a UOA you'll never really know how well its doing. Saying "it's not blown up yet" isn't really a great way to think. Blanket recommendations are dangerous, an oil choice may well work for you but not for someone else. Much in the same way that if you like a certain type of running shoe and it's perfect for you, it might give your friend bad blisters or pains in their knees. It's what you're doing with the car that's important.

Thanks for your time.

Craig

TonyBurns

iTrader: (3)

No I think you must be a graduate that has no experience in the real world
Can we start with the basics?
You say that every oil is too thick on start up? what BS, if anything you can have an oil that is too thin on start up and that due to the friction caused between the 2 surfaces, can cause the oil to "evaporate", meaning you then have zero protection.
Metal on metal is not good for longivity btw.

You also seem to think that lower is better, also incorrect, you have not even taken into consideration ambient external temps, a 10w will still provide good protection but will take longer to warm up over a 5 for instance at 30 deg c, this is well within the operating temperatures of both oils, it DOES NOT mean its not providing protection, if you have forgotten, oils lubricate, and you pick one that does it better (and no, that does not mean lower is better, it all depends on the application, materials and temperatures).

You also sit there and call people ignorant, well the ignorance is yours as the manufacturer will strip the engines and check damage on cold start ups on general use, check the engines using micrometers, different conditions, run them for hundreds of thousands of miles, put them through hell and not only choose which oil is best for every day use, but also recommend how long this oil is good for during those applications (varying conditions etc) between changes.
You basically say that if you listen to the manufacture then your an idiot, so your recommending a 0w oil in an engine where its NOT recommended means that your an idiot? or can people just send you the 3k bill when it causes main bearing failure??

Craig, there are people on here who are engineers, those who build engines, run different lubricants to find out which one is best for that application, have people bring them cars due to running the incorrect oil in an engine because people have recommended one that cannot provide the correct ammount of lubrication, leaving them with large bills, so please, we understand what oils to use with what applications, the OP wanted to know what oil was good for his 130k mile engine, so a unit with wear in there that you dont seem to have taken into consideration, we recommend a thicker oil at hot weight, even cold but that is still within the operating temperatures, and we also recommended a slightly thinner cold weight oil for winter as even though a 15w is good for about -10 (off the top of my head, cannot be bothered to look just yet as just in work), a 10w50 would be better for that time of year.

Anyway, let me finish my cuppa.

Tony

PS, Shaun, spot on mate

NEILB1

iTrader: (9)

pmsl so what we agreeing on fellas?

10w 40 semi as i need oil today for my bugeye wrx with 84k on it and will be running near 290 in a month or so

All i need is a grade chaps lol

Henrik

iTrader: (5)

captain_anonymous_2003, I think you make some good points here, and I agree there is a lot of group think about oils.

I'm currently running a 10-60W, but then I mainly intend to take my car on track until I change oils, and I usually end up at about 110-115 degrees oil temp before I come in.

However, like you say this oil may be way to thick for normal driving (90 degrees). Even on spirited on-road drives I have *never* seen past 100 degrees even in height of summer.


Food for thought - I'll definitely consider a different oil next time I change if my use of the car changes.

captain_anonymous_2003

I can't begin to tell you how wrong you are. To suggest that an oil is too thin on start is utterly ridiculous and if you said that to Castrol, Shell or Mobil engineers you'd get laughed at, if you don't believe me make some calls I guarantee you will get the same response. Oil manufacturers have been trying for years to get oils to be thin enough at start. That logic you have is totally absurd, if that's the case why on earth would an oil THIN UP as it heats up?

NO OIL IN EXISTENCE THAT YOU CAN BUY IS TOO THIN ON START THEY ARE ALL TOO THICK, please, if you take anything from this conversation take that. Think about this, why do you think 5W-50s are expensive? Because they're easy to make? NO, because they're not. If you could make an oil with a thickness of 15 mm^s/s @ ALL TEMPS from -50C to 170C you would be.. a BILLIONARIE! Castrol, Shell, Mobil them all, would be all over you. That's the holy grail of oils you have right there, but it doesn't exist. So you have to compromise between cold start protection and race performance protection.

Do NOT think of oil thinning up as it gets warm, think about it thickening as it cools down. Thick is bad, anything around 10-20 mm^2/s is good over 20 mm^2/s and it's getting bad. This is why every oil tries to get to a thickness in that range at 100C, it's not a coincidence! I'm not making this up look at your oil specs.

The oil thickness is too high to be supplied at sufficient quantities to the engine when the engine is cold, this is why you get bad engine wear on start, this is why it's recommended not to run the engine at high RPM. Because you cannot supply oil fast enough due to the pressures it creates due to its thickness! As it thins due to heating up it becomes easier to supply it.

I ask you again, explain WHY it is beneficial to have an oil that is 130 mm^2/s @ 40C rather than 75 mm^s/2 @ 40C? And bearing in mind this will only get worse as temperature reduces! So in winter it'll be awful frankly. What is the benefit, both are too thick at that temperature but one is far worse than the other. Why would you select something that you know is even thicker than another at cold start any yet similar at operating temperature?

You select a 15W-50 for race applications, where that engine is stressed ALL the time and rarely cold started. For those applications it's a good choice. It's cold start protection doesn't matter as much as the high temperature protection during racing, so a 10W-50 and 15W-50 would be on my list as options. However for driving around town, and going shopping, how on earth is that sensible? Why would I select it? I wouldn't, I'd think 'hmmm lots of cold starts.. short trips.. I need something that gives me the best protection I can from cold.. I'd start with 0W-40. Take my car as an example, if I can get away with it and my consumption doesn't rocket through the ceilling (there is only so much I am willing to put up with before it gets silly) I will look at a 0W-30 and do another UOA to see how that does.

As for the personal attack on my education, all I will say is I am extremely well educated in a highly mathematical field and well beyond graduate level. That is all I have to say, I don't believe in ramming things like that down peoples throats, I think it's vulgar unnecessary and education isn't the be and end all, it's just the route I took.

I would add, have you ever done a UOA? If not how do you know your oil isn't causing high wear? You'd only know when it's too late if you don't do UOAs.

oilman

iTrader: (9)

Just read through most of this thread, but I don't have time to read it all.

What I've read is a lot of theory, but not enough to deal with real world applications and peoples preferences.

Due to the way the Impreza engines work, a 0w-40 like the Mobil 1 is often not liked due to the amount of noise the engine makes on start up. With the Mobil 1 being a PAO synthetic and relatively thin when cold, it means that the pistons can sound quite rattly and then the oil doesn't help in cushioning them. Although there is no technical problem with that, most people don't like a car that sounds like a bag of spanners. We even get reports that people don't like the amount of noise the car is making with a 5w-40. People often prefer a 10w in a classic Impreza due to the larger engine tolerances causing a fair amount of noise when cold. I know that the amount of noise produced is only a problem in people's heads, but it's those people that are paying for the oil. Bearing issues are a real problem though.

Also mentioned is a 15w-50 and that is an oil that I wouldn't really consider unless the car is a heavily modified one, run mainly on track or the person wants a brand of oil unavailable in a 10w-50. A 15w-50 is a little more stable when at extreme temperatures so can be a good choice in a track only car, where cold start protection isn't as important as high temp protection. For road cars, I'd always go for a 10w-50 rather than a 15w-50 if given the choice.

Cheers

Tim

gallois

So what we need to see for an informed decision is -

the recommended oil pressure at 100deg at set rpm's for the car.
the actual oil pressures at set rpm's, and oil temp parameters of the actual car, and work it out from there.

after all, regardless of oil weight, it is OIL PRESSURE that protects the bearings, oil flow is for every thing else?

Good pressure with thick oil, but poor flow. or
Thin oil, Excellent flow, but lower oil pressure.


BTW i cannot see why people are getting ar5ey by captains posts, quite informative.

captain_anonymous_2003

Thank you, I get a tiny bit of support. I am just trying to help people look at oil choice differently to just accepting a recommendation. I would also add UOAs on oil changes to that. I think they are valuable and give you a lot of useful information.

stanmo

iTrader: (1)

So, if 0w oil is still too thick for starting conditions, would something as primitive as an oil sump pad heater be any use to those using 5/10w ? Heating it for a few hours beforehand to around 40-50 degrees centigrade ?

I tend to do short journeys, 9 miles or less, which I understand is particularly bad for oil, as it never gets really warm.

captain_anonymous_2003

Ok, let's be sensible here. I think people will unnecessarily panic about oil and realistically using an oil which is not the best for your operating conditions (and that's what we're talking about here) won't destroy your engine in seconds. We are talking about an engine requiring rebuild work earlier than it might due to premature wear. Engines will last a long time even on oils that don't protect as well as another at cold start, so please don't panic.

What you say here is correct yes, if you did heat the oil first and then started the car you'd get the oil to the correct thickness for operating conditions right away. But we have to be realistic, these are cars, not jet engines, all I am saying is look after it, but going crazy and fitting bigger pumps, oil sump heaters and so on is really going a bit too far. Don't worry about your oil choice so much you can't sleep at night, just get a UOA done on your next change and have a look at the results. After that and based on your own data from your own car/engine and driving styles, make a decision based on that and you'll be fine.

When you have your data why not talk to Tim above (Oilman). I can completely understand what he is saying about the noise, and can see why there are those that would scare as a result of more engine noise. If he's ok with it have a chat with him about your next oil change based on your driving habits and your UOA. The recommendation will be personal to you then

The whole point to my posts is quite simply. Ignore blanket recommendations by anyone unless they have taken the time to understand how you use your car. And take the time to understand how oil works so you can ask the right questions and make a selection that's good for you. And then back that up with UOAs. And then, frankly stop worrying about it and ignore anyone who po poos it. If they use their car differently to you a different oil for them might be a better choice, it doesn't make your choice any less valid.

In the case of the M5 oil is a hot topic, there are those that will swear (blindly normally) by TWS and those that take the time to understand their needs and make a selection based on that and analysis. Generally if you do that for most of us we go with something lighter.

I just get frustrated when you hear "15W-50 Silkolene.. anything else is rubbish"... it may be the case for them (although in most cases they have no idea what it's doing anyway as they've never looked into it, they just assume because it still works and it's quiet it must be perfect for it, this is not necessarily so of course) but not the case for you. I am genuinely trying to help you lot here!

stanmo

iTrader: (1)

Having just done a rebuild, I figured an inexpensive pad heater would be the least of my concerns, so I'll go along with oilman and Iain Litchfield's recommendation of 5w40.

I have also noticed my wife's legacy gets better MPG moving to a 10w40 oil from the thicker stuff that the garage put in last; so as long as it's a decent quality oil, there is a minor cost benefit too.

btw, I've seen very similar, almost verbatim posts on other car forums, so I guess you've been around ?

TonyBurns

iTrader: (3)

I bet you they wont, they know that lubrication is what you need, what your saying is that everything is too thick to go in an engine, what Im saying is that you need good protection and going too thin isnt a good idea because friction causes heat, if you heat something up thats (according to you too thick) it will evaporate (are YOU starting to understand here?), so basically you go for it from cold (not a good idea anyway) your saying your car is going to be lubricated too heavily, where as we actually say, a 5w/10w or 15w will still give you good protection but each one will (from 5-15) be quicker to slower to reach a good nominal operating temperature (but by that time the 40/50 will be what your looking at).

If you want to go into molecular structure or tollerences between surfaces then go for it, the ignorant one is the one who is telling us that a 0 cold weight is good for our cars, when its proven to cause issues, and then your saying that its down to application, which we agree with, it is, but your forgetting about wear in an already high mileage car, now your talking about saving a mile or 2 on the engine due to wear, yet there are a few out there that have run on 10w40 semi synthetic oil all of their life and have 170+k miles on them, and some that have run 5w30 which have gone pop at 30k miles, so carry on, answer Paul's and Simon's questions, I will just sit here and laugh at you as I would have to be completely stupid to follow your advice on oils and would rather stick to what my (very good) mechanic recommends

Tony