LOW weight (5w-30) vs. HIGH weight (15w-40+) oils...

First off, this thread is EXACTLY why I'm willing to pay $$ for a "members subscription" to FChat. My head is spinning. Can we possibly pull this discussion from the lab, and back into my garage?

My 1990 348ts specifies Agip Sint 2000 10w-40. In reality, the car is running Mobil 1 5w30 right now. The car is stored in an NON-climate controlled garage. On a cold (but dry) winter day when the roads are clear, I want to go driving. The ambient temperature in my garage before heading to Starbucks for a latte will be around 35deg F. In this scenario, it sounds like AEHaas might recommend 0W40 or the lowest "W" number I can find while maintaining a 40. The cold yuckiness of winter and sludge-like startup viscosity must cause incredible wear on my 15 year old car, right? But after I've enjoyed the Starbucks latte and the car is toasty warm, the "40" action is just fine for spirited --non track-- driving. By spirited, I mean shifting around 5K, tossing into corners, lots of unnecessary but emotionally satisfying revs & shifts. Car is driven once a week -- maybe 70 miles each time.

In the summer, when I return home from work, the temperature in the garage could easily be 90-100 deg F. Gable vents and fans are pumping away, but it gets hot. In that environment, does that "W" number matter at all? Would 0w make much difference compared to 5w in terms of start-up wear?

What's the deal with Shell Helix? Does the presence of a Shell emblem on Schumacher's car mean it's THAT much better? It's nearly twice the price of Mobil 1. Believe me, my wife has taught me that PRICE = QUALITY (wink), so I'm wondering if $13/bottle makes sense.

With 5w30 Mob1, nothing leaks from the car. I could store wedding pictures under the vehicle, and they'd be fine.

Can somebody possibly give me some real world, non-track, spirited, USDA Zone 7 ideas?

Thanks in advance!
-Daniel

 

http://ferrarichat.com/forum/showthread.php?t=9832

 

Thats an interesting thread and yet my Ferrari delaer and rwo ithers I spoke to wold NEVER suggest using mobil 1

 

The "W" was put into use, defined by SAE, API, ASTM. I quoted these people. It does not matter what any other person says the definition may be. It does not stand for "winter". It is a laboratory testing specification.

aehaas

 

I have been using 5w-50 in my 308 for some time. After a lot of study of viscosity charts I came to the conclusion that low weight oil is very important when the engine/oil is cold. My study seems to be working in that the cold start oil pressure is right on at the same mark as my hot pressure. The idea is to get lube to every part of the engine asap with thin oil (when cold) and let the oil thicken as the you get to running temp to achieve the right pressure level. So far so good.

 

hga,
That is interesting, but if you check the charts posted by Aehaas, you see that the Castrol Syntec 5w-50 seems to act more like a 20 weight oil at 40 degrees Celsius, in spite of it's 5w rating.

http://www.ferrarichat.com/partsandservice/Oils%20Specs.htm
see sheet 3

 

HQA,
The oil does not thicken as it gets warmer. It still gets thinner, but a multiweight oil doesn't START OUT as thick as a single weight oil would at teh same low temperature. SAE defines the weight of an oil as its weight At 100 deg. C. Your 5W-50 oil is "5 weight" when cold, but remember that the 5 is actually defined at 212 F (100 C) which is not the temperature of your engine when it's cold, so it's the equivalent of about "40" weight. (Keeping in mind that SAE "weights" are arbitrary numbers that do not correlate directly to any viscosity measurement. I know, this is the stupidest convention of naming in automotive history). Suffice it to say, it is impossible to make an oil that is thicker when hot!

Birdman

 

Its not that the oil gets thicker when its hot. Multi viscosity (10w - 30) oils start with 10w oil. Conventional oils then have polymer "additives" that are long chains. These coil up when cold and therefore do not affect the viscosity, but when hot they uncoil and increase the viscosity. Hence you 10w- 30 or 10w- 40.

The larger the difference between the two numbers the more additives requied. Such as 10w- 50 requires more sdditive to reach 50 than 10w-30 to reach 30 when hot.

The problem with additives is that they breakdown over time. That's why change intervals are short. It is also why few cars use 10w-50 or even 10w-40 anymore.

Nowdays it's generally better to use oils with the least change in numbers.

 

What Richard is saying is less true today than 5 or 10 years ago. The additive packages are different. Also, it applies mainly to mineral oil based lubricants.

Most synthetic oils are designed from the start not to require any viscosity improvers. This is why they last much, much longer. In fact, the viscosity changes very little. If you took the oil out, cleaned out the accumulated impurities and added back the specialized additives it would be as good as new.

Most synthetic oils are actually a single weight oil. The properties however are as the multi-viscosity mineral oils.

aehaas

 

I think you all might be trying to split atoms... I change my oil every 2.5K to 4.5k depending on my mood. I always use additives to help it along (chlorine based and zinc dithiophosphate based). I like several brands and try my best to use single weight whenever possible..multiweight is for those who don't want to let it warm for the important 3 minutes.

I have driven more than 500k miles in my short life and have never had a bearing failure, camshaft wear, heck my engines don't even have a ring ridge after like 100K miles.

I learned a long time ago to pull the dipstick and feel the oil.. I can tell when it needs changed. When I start having bearing failures with my 8500 rpm vw flat 4's I'll read all these bickering replies about oil.

Now I just dump in the oil...start it up... and put a load on it when it feels warm..

Don't be afraid to touch your engine... use all your senses..

"Come to kindly terms with your ass, for it bears you.."

 

I was just today told by the service manager at FOA that they received a directive from FNA not to use any 0w oils in Ferraris that they service.They use 15w50 in my BB512i and it seems to work fine.

 

That confirms what Castrol told me dont use 0........ in this engine

 

I have had numerous discussions about Ferrari in general and my 575M specifically with these people from FNA:
Adam Williams, Christopher Gallagher, Adam Rowley
These are the tech guys there. It is known I am using 0W-20 oil.

I have had numerous discussions with Craig Lortie, the USA tech man for Lamborghini. He was particularly interested in the quieting effect the 0W-30 Mobil 1 oil had on my wife's Murcie engine. I just changed out the Agip 5W-40 at the 500 miles mark. As of today I have 750 miles.

I have spoken with chemists from most oil companies.

My guess is that they will lower the oil spec in the future. They have been doing this routinely. It was 20-50, then 10-50, then 10-40, then 5-40 and a little known fact, new Ferraris are delivered with Shell Helix 5-30 in there.
This trend has also been going on with all other manufacturers. These are the facts.

Several auto manufacturers are now spec'd for a 0W-XX oil. It has Nothing to do with engines being of closer tolerances, Nothing.

ANY person who tells you that a 0W-XX oil should not be used has no knowledge of oil chemistry. If they tell you this, they do not know what they are talking about. I would be suspect of any other information they give you.

In discussion with such a person I would ask why they do not want you to use it. When one of those people answers that question it will be clear why they have no knowledge of oils. I find it interesting that there are so many experts when it comes to oil. Most information they give out is incorrect and in some cases detrimental. If you want to know something about oil ask a person who knows something.

aehaas

 

Regardless, if you use a 0w oil in a Ferrari or any other car for that matter, and have an engine failure, they will claim that the failure was caused by the 0w oil. Of course you can then sue them and hire an oil expert to testify vis deposition that the 0w oil did not cause the failure and you may even win. But, look at all the hassle and expense you will face; and for what ? I recommend that you use the oil called for in your car's manual. What will take hurt ?

 

A) perhaps the 5W30 is breakin oil
B) Nascar guys are now using 0W20 for qualifying and 0W30 for racing
b) Nascar guys are using teflon lined bearings with these thinn oils

There is a way to tell what oil is right for your application, it just takes a little time and the equiptment that comes in you car: namely the oil pressure guage and the oil temperature guage.

If the oil is too thin (warm to hot:the number after the W) the oil temperature of the engine will be higher than with the ideal oil because more friction is occuring.

If the oil is too thick, the oil temperature will rise because it is taking too much power to pump the stuff around.

By experimenting and keeping notes, you can determine what oil is best for your car and for the different operating conditions of your car. By assuming that Ferrari is not way off base with its original specification, you can try a heavier oil and then try a lighter oil and useing the guages to tell you if one choice or the other was in the direction you want to go. By making small steps and being aware that you are using your car as a testing device and changing the oil if its wrong even if the millage has not accumulated, you can avoid engine wear durring the experiment. Oil is cheap, engine rebuilds are not.

 

I understand what you mean that the oil doesn't actualy get thicker. But there seems to be a viscosity differential as the oil temp changes as compared with the thinning rate of single or narrower band multi weight oil. If that were not true why would my oil pressure be static hot or cold as soon as I changed to 5-50? My previous pressure was 8lbs higher at cold with 20w-50. Now the car is at the normal hot pressure level all the time. Do you think the engine wear will be reduced by the now lower cold pressure as long as the spec pressure is maintained at any temp?

 

It's been my understanding that manufacturers are using lighter oils because they yield better fuel economy as per federal requirements. They do want all of you to go out and buy new cars every 100K or so!

I like to use thicker rather than thinner oils. Keeps me away from the dreaded oil shear at the sacrifice of a very small waste in pumping effort and lost parasitic drag.

Since all road vehicles are air cooled I look to my water system to keep my overall engine temps within reasonable limits. I have on other vehilces used extra oil coolers with thermastatic switches. My 308 temps run within factory specs so I will stick with the Kendall GT1 it came with.

Back in the 70's there was some research done by some vw people about engine life. They found that engines warmed up for a few minutes before driving lasted 60% or so longer than those that were started and used immediately. My experiences have been similar.

Even though I am in research and work in a laboratory I have only been a hobbyist with car engines. Still, I seen to be able to squeeze large amounts of life from all engines I have owned/built.

I'll gonna stand by frequent oil changes and a proper warmup for good performance and longevity. Life is too short for me to split hairs about the "perfect" oil. I've never found one that wasn't good enough. If anybody has a recommendation of an oil brand to avoid I'm all ears..

I definetely don't want to perform any Ferrari engine work quite yet..

 

I have been studying high temperature shear viscosity but there is limited data. This test is performed at 302 F. It is thought to be the nominal bearing temperature in a normal engine.

SAE J300 defines the standards for min. viscosity for 20 wt. oils as 2.6 and 60 wt oils as 3.7. This is a difference of about 1 cP. This goes back to what I have shown in the past. Oils differ greatly at startup viscosity. The difference is negligible at operating temperature and even less at the extremes of temperature.

aehaas

 

I would like to add that bearing temperatures are relatively low. It probably gets to 400F or higher at the valve stems, rings and in turbos. Engine wear however is still minimal at these conditions. It is the start up condition where the problem is greatest.

I agree that oils are thinner to increase mileage but also HP. I disagree that they are thinner to decrease the longevity of engines. In the late 60's and early 70's engines only lasted 50 - 100,000 miles. Now they last 100-200-250,000 miles or more. Engines are smaller, run at higher stress and temperatures and higher RPM, and loads. The longevity is not in spite of but rather because of modern (and thinner) engine oils.
It is also because of increased use of synthetic oils. They are all thinner than dino oils of the same rating. Let me repeat this last one. Everyone agrees that synthetic oils are better and give longevity. Guess what, they are thinner.

Conclusion: Use the oil viscosity that you need for your engine at operating temperature. Make sure the 1st number is the lowest. Use 0W-XX.

aehaas

 

working in concert with modern materials and modern machining and assembly methods.