Ultimate Motor Oil Thread or Why we hate CJ4/SM oils

[333pg333]

What about all these people that suggest that using a 15w or 20w is too thick at startup and this is where all the damage occurs?
I believe there is meant to be a new Mobil 5w/50 but others have said that having such wide range can be a bit misleading. That they don't really work as a 5w on startup and 50 under regular or race operating temps.

They're also the ones that seem to favour BITOG which also seems to favour 0w/30 or 5w/40 synthetic oils in everything. Here is an excerpt from another site quoting the poster and Haas:




"This is a very difficult topic to comprehend. Everybody including good mechanics think they are experts in this field but few understand engine oils. Most of what I hear is the opposite of the truth. It is however easy to see how people get mixed up as there is always some truth to the misconception.... The greatest confusion is because of the way motor oils are labeled. It is an old system and is confusing to many people. I know the person is confused when they say that a 0W-30 oil is too thin for their engine because the old manual says to use 10W-30. This is wrong." — JE Haas.


i've heard several of the smartest guys on the Porsche 4 cylinder forums saying 0w40 is way too thin. and by the same token, Mobil doesn't even offer a 10w40 anymore, except in a high-mileage formula... why ? too thick at startup. today's synthetic oil technology offers significantly, better options to help our soft engine bearings run as far as possible.

there is a great article on this subject at the following link;

Motor Oil 101 - Bob is the Oil Guy

Motor Oil 101 - Bob is the Oil Guy

Motor Oil 101 - Bob is the Oil Guy

Motor Oil 101 - Bob is the Oil Guy

Motor Oil 101 - Bob is the Oil Guy

Motor Oil 101 - Bob is the Oil Guy

Motor Oil 101 - Bob is the Oil Guy

Motor Oil 101 - Bob is the Oil Guy



0w synthetics flow like regular oil does a few minutes after startup.

that is so say, it has the same thickness when the engine is ice cold as a 10w, or 15w oil has after the car has been running a while.... but it does this when ice cold--the moment when 90% of the damage we do to our engines occurs. if this concept is too radical for you all, then consult the automakers and their white papers. ask yourselves why a Ferrari F-430 has a maximum range between 0w30, 5w30 and 0w40 synthetic oil. why ? startup. the effin' engine is expensive to fix. so the solution is not to destroy it in the first place.

oh, our cars are different? yes, our cars require at least a 12 weight oil at 200 degrees. that would equate to 40 weight oil. show me a 944 that has failed running 0w40 or 5w50 oil. they fail because of damage done to the bearings during hundreds of cold startups. then finally being pushed under high performance after the bearings are already shot. but the posters say, "my oil failed today and i spun my number 2 rod bearing"... no d_ckwad, your bearings were destroyed before you even started the car... 40 and 50 weight oils run at something like a 12 and 17 weight respectively at operating temperature. the key is never getting to the point where the bearings have been damaged in the first place.

synthitic 5w50 is not a magical, multi-grade synthetic that will fall apart like it's conventional mineral counterpart... but the snake oil salesmen here will keep telling you all to run 15, 20w50 oils when it's freezing cold outside. the maximum thick oil we should ever be running in the winter would be Mobil 1 Racing 0w50 oil (the best oil on earth, period). or the less costly 0w40 or 5w50s.

but, wtf.... there's no cure for stupid."

turbocharger video http://www.youtube.com/user/OfficialMobil1#p/c/3/j-4WnBc3CKY

[HarryD]

Hi Patrick:

Let me start by saying, your car, your money, your choice. Frankly I do not care what you put in your car.

I skimmed the article you provided a link and noted that the writer glossed over the need for high pressure wear additives (such as ZDDP) in flat tappet engines.

The bulk of the aerticle is focused on viscosity selection and I am choosing to not get into that issue other than I will continue to follow the vendor recommendations for my cars (20W-50 for my 1973 911, 5W-30 for my 1996 Ford Windstar, and 5W-20 for my 2006 Ford Focus).

I disagree with the writer opinion that ZDDP in highly stressed flat tappet engines (such as the 911 air cooled engine) is unnecessary. There is plenty of test results by SAE to show that to prevent your cams from going flat, you need a high pressure wear agent such as ZDDP. This is backed up by reports from engine builders that have reported that cam failures took off when the SM oils were in widespread use.

But, as I said in my first paragraph, you are free to use whatever you like.

[333pg333]

Harry, if I am reading you correctly, you are reading me incorrectly. I think you might have missed that I was essentially quoting 2 other people hence the "" marks. Oh, and the link to the M1 turbocharger clip was part of the quote. I found it laughable that we are meant to believe that an alleged technician holding up 2 bearings, one damaged and the other looking brand new, was meant to convince us to use their product.

I in fact use and link this Pelican oil thread on a repeated basis to point out what I believe to be true about much of what has been advised in here. I use a 25w/50 VR1 racing oil year round with excellent ZDDP content. My reason for quoting the above was desirous of getting an answer in regards to the commonly trotted out theory that e.g. a 20w/50 is too thick an oil in most conditions and damages engines on startup?

[richardlw]

Harry, you are right on.
Just one thing I would suggest: When they recommended 20W-50 in 1973, There was very little or no technology for a 5W-50, and they wanted something with a 17-19 cSt at 100C, possibly knowing that in racing conditions you may well be running 115-120 where that oil would be around 13-14 cSt.

A true synthetic 5W-50 is a 50 that acts just like a 5W in the cold start tests. It can also be labeled 10W-50 or 15W-50. Or even 20W-50 for marketing sake. In general it will have the same HTHS as a SAE 50, Although I'm surprised at a much lower HTHS on a couple of them, indicating that they aren't 100% PAO/Ester blends, but include some VI improvers.

So a good 5W-50 gives you everything a 20W-50 gives you, with better startup protection.

I did a test a couple of years ago. Changed out the 15W-40 that I had always used in my Turbo Diesel 4Runner and put it 20W-50 (engine had 60,000 miles on it). The immediate change was the oil pressure light took 6 seconds to turn off on each start-up instead of 2 seconds. After 4 days of 4 to 6 starts per day, I changed back to 15W-40. Both oils were listed in the manual for that engine, but one gave 4 seconds less running dry. Both were the same brand, base oil and formulation.

[333pg333]

This is what I'm essentially asking. If these oils with extreme ranges like a 5w/50 really do everything that their proponents suggest, then why aren't we all using them? (Provided they have all the other requirements like ZDDP in decent ppm.)...or, are the 20w/50 really that bad on startup provided you're within the temp guidelines?

[HarryD]

I am far from a lubrication expert, but I do know that a 911 Air cooled engine in civilain service (not heavily raced) using the factory recommended 15W-40 or 30W-50 oil can have the botom end last 200,000+ miles before needing a rebuild (barring some catastrophy). This tells me that oil starvation ot the lower bearings is not really an issue.

While I would agree that the cold, thinner oil would flow to the bearings a few seconds sooner, I am not sure it it truly an issue. Also, given that most ofthe low cold vicosity oils lso have a reduced level of ZDDP, I am not sure it is the best for the longevity of my engine.

[richardlw]

While "most" 20W-50 oils have reduced protection, meant for worn out cars, or cheap fixes to consumption problems or ignorance, there are many 5W-50 oils out there with the ZDDP you want.

Run your own experiment if you want, as I did. Decide for yourself.
I run a CI-4 SAE 5W-50 in these cars, frequently taking first place. They don't have the flat tappets, but do run at their top rpm most of the race.

[Por_sha911]

Some of these oil reccomendations are for vehicles that see RPM ranges from 1-3k.
Our air-cooled cars run best from 3-6k

[richardlw]

The higher the rpm, the thinner the oil should be.

The hidrodynamic lubrication is requires an inverse relationship. Too much viscosity causes too much resistance and heat.

[winders]

Originally Posted by richardlw

The higher the rpm, the thinner the oil should be.

The hidrodynamic lubrication is requires an inverse relationship. Too much viscosity causes too much resistance and heat.

Is this why 600cc motorcycles that rev up to 16,000 RPM have a typical recommendation of 10w40 in their owners manuals?

Scott

[911pcars]

Viscosity requirements at any rpm depend on the protection the oil provides. Viscosity isn't the only factor that protects moving parts. If a given lube oil provides the needed protection, sealing capabilities and other qualities at a lower viscosity, then why not?

Sherwood

[j911brick]

Originally Posted by winders

Is this why 600cc motorcycles that rev up to 16,000 RPM have a typical recommendation of 10w40 in their owners manuals?

Scott

Its a bit more complicated than that. It mostly depends on how the engine was designed (IE: clearances and pressures) and for what oil. Oil has a fluid friction and that robs power. But oil is also the cushion that keeps the parts from contacting each other. You get more power with thinner oil, but you lose protection. Oi that is too thick will have more fluid friction and will not wash off the parts fast enough, which will cause wear (and heat). Basically, the right oil is the oil for which the engine was designed.

Also, see what Sherwood said.

[winders]

james,

Yes, I know it is much more complicated than that. What richardlw wrote made no sense. The oil viscosity requirements of an engine are not directly related to RPM.....

Scott

[ant7]

Originally Posted by richardlw

While "most" 20W-50 oils have reduced protection, meant for worn out cars, or cheap fixes to consumption problems or ignorance, there are many 5W-50 oils out there with the ZDDP you want.

Run your own experiment if you want, as I did. Decide for yourself.
I run a CI-4 SAE 5W-50 in these cars, frequently taking first place. They don't have the flat tappets, but do run at their top rpm most of the race.

hI Richard,
sorry All for taking this very interesting thread off track for a moment, but i must say, thats a mad looking vehicle, what events do you use it in ???
Anthony.

[richardlw]

Oil viscosity in anything, engine, compressor, gear box, etc, is inversely related to speed. Obviously it also depends on the design of the engine, gear box, or whatever, but for any given equipment, it is inverse. There is an optimum, which will give you the least temperature and resistance. Part of where multigrade oils come in.

Off road rallys. The top one just took first place in the one from Santa Cruz (Bolivia) to a place down near the Paraguay/Argentine border, about 410 miles of dirt.

[mikesride]

1200 ppm of zinc
1400 ppm phos.
15w40 John Deere (whom I work for)
Would this be an acceptable oil for my 82 3.0l stock ?
Thanks guys!

[GaryR]

Originally Posted by mikesride

1200 ppm of zinc
1400 ppm phos.
15w40 John Deere (whom I work for)
Would this be an acceptable oil for my 82 3.0l stock ?
Thanks guys!

Lots more to it that that - a breakdown of all detergents, viscosity modifiers, how it breaks down, etc. etc. etc is important also..

[hcoles]

How about finding out who makes it. This might help. I assume that JD doesn't have its own oil factory. Sounds good on the surface.

[911pcars]

Originally Posted by mikesride

1200 ppm of zinc
1400 ppm phos.
15w40 John Deere (whom I work for)
Would this be an acceptable oil for my 82 3.0l stock ?
Thanks guys!

Comfort level would be higher if the operating conditions of a John Deere are similar to a 911. E.g. Does a JD rev to 7000 rpm? It may not even though the typical JD loads are higher at lower rpm.

Sherwood

[lupin..the..3rd]

Originally Posted by cnavarro

A good example of this is the new LS7 Corvette engines. They call for a 5w30 oil. If you put in a 15w50 (or 20w50), oil temperatures actually jump 20-25F under the same conditions.

Funny, so does a 911 when you put -50 oil in it.

-50 and -60 oil is too thick for these engines. In fact, it makes them run hotter. The large pressure and scavenge pump of a 911 takes hp to run. And it takes more hp and creates more heat to pump thick heavy oil, particularly in high-rpm track driving. I've done back to back comparisons at the track, and a -40 weight oil runs cooler than a -50 weight in a 911 under identical conditions. 220F was my highest temperature on the 10w-40, while I saw 230F on the 20w-50. Same car, same track, same ambient temperature. Bone stock 1987 Carrera, with stock oil cooler.

And to those who say a -40 weight is "too thin" and it "doesn't protect the engine" and other nonsense, here's a UOA for your consideration. thicker is NOT better.

This oil had 2000 street miles (mixed city / hwy) plus more than 6 hours of track time in July and August, the hottest months of the year.

This is Redline 10w-40. Note the extremely low wear metals, and also note the high Zn and P content. This oil is in such good shape still, I should have gone quite a bit more on it before changing it out. Single digit wear metals after 6 track hours is outstanding.