Potomac-Greg

I just did a change with Mobil 1 (extended performance) 15W50. I'm going on-track next week and it's going to be HOT. I ordinarily use Castrol GTX.

My concern is the dreaded #2 bearing. I have to assume that if the bearing failure is due to oil starvation, that a synthetic will provide a marginal advantage.

ehall

There is enough published evidence, both technical and anecdotal, to validate the point. All you have to do is search for it. That said, on newish engines, the lack of ZDDP isn't a problem. It's only a problem for older, flat tappet cars. But, like it says, it is like religion. It's pretty funny that is is like that. It really doesn't make much sense. ROFL

CurtP

I call shenanigans. I've yet to see any compelling proof - just opinions, speculation and "facts" as published from manufacturers of ZDDP additives. If you're not doing oil analysis, then there's no way for you to know what's really happening. ZDDP is not the only anti-wear additive in oil.

I don't believe there's a blanket answer either. What works well for one person, their car and their driving style will not necessarily work for someone else. I try not to prattle on about specific brand/weight/series of oil, but I will preach about oil analysis. As an added bonus, analysis can give you a huge insight into other issues with your engine - like bearings that need to be replaced, coolant in the oil, etc. What's not to love other than the $22 per sample lab charge?

ehall

FWIW, I've never read any ZDDP manufacturers "facts" nor do I believe there are any facts to be had from a manufacturer of a product. Everything that I've read has come from independent sources.
Much like why I don't buy Mobil 1, even though Porsche says I should. Afterall, they are Porsche right? They must be THE authority...cough..cough...sponsorship dollars...cough.
And I agree about the value of analysis.
But alas...it is like religion. Nothing to be gained in the discussion.

alordofchaos

Doug Hillary does... holy crap, the amount that he knows about oil is amazing then again, i think that's what he has done for a living for the last few decades

search on his name for his posts, you'll find an amazing amount of oil info (independent testing lab, too ) including a dozen oil analyses done on his 928

Potomac-Greg

FWIW (which is my way of saying that I have no idea if this is of any value to anyone) but Castrol Syntec has a new 20W50 product that is specifically made for older cars and has higher levels of zinc.

The motor oil market has become like the market for printer ink cartridges. There are SO MANY variations that it is virtually impossible to find what you want in the stores.

m73m95

To be competitive, all "good quality" oils are about the same. The additives vary a little from one to the other, but not enough to notice.

I've seen people get 300k miles out of thier engines using nothing but regualr, dino oil. (some are even on the 'list). Synthetic has better heat handling properties than dino oil. The molecules are also smaller. But pitting one oil aginst another will only show slight differences. I'm sure ZDDP is a great anti wear additive, but thats only 1 small factor in how long an engine will last.

rmconner80

Mobil 1 0w40 has 1000 ppm phosphorous.

Mobil 1 15W50 has 1200ppm phosphorous.

Neither are therefore ILSAC GF-4 compliant, which is the new rule that had ZDDP (phosphorous) amounts lowered below 800ppm in most motor oils. Maybe it's "not enough", but in either case it's higher than a compliant motor oil (and theoretically "better" IF we assume ZDDP is indeed the critical path to preventing premature tappet and cam lobe wear - this may not be the case).

http://www.mobiloil.com/USA-English/...duct_Guide.pdf

I still think that in general, motor oil is motor oil. As long as it's fresh and good quality and used with a new filter.

JonH

Surprised it hasn't been mentioned yet, so I'll chime in with what I use just because you know this thread is going 10 pages min. I can get a case for around 45.00 somewhat local

Brad Penn. (old Kendall One) 1,500ppm Zinc

http://www.bradpennracing.com/default.asp

pkt1213

This is the artical I was talking about.

http://ferrarichat.com/forum/faq.php...tor_oil_basics

ehall

There is one BIG disconnect with what this article says, though I believe he is generally correct, and the 951 environment. The disconnect is that our cars weren't machined at the same incredible tolerances as a Ferrari 550 or 575. Our cars are 20+ years old. They also have flat tappets.

His analysis of the inverse relationship between pressure and flow is spot on, in absolutely ANY hydraulic envirnoment. However, our cars have MUCH more wear, and for the most part, machined sealing tolerances, due to age. As such, though greater flow is what we need, we, for the most part, can't keep the oil in the car! So we are forced to make a compromise. In essence he makes this point in the post/article.
A racing 951 gets MUCH more wear, but also MUCH more attention than does a dayly driven 951. A thinner, more often changed oil, is good practice in a race car, not only for the temp. related issues mentioned, but also because that oil probably won't be there by the next track session.

What the higher levels of Zinc provide is a surface, somewhat similar to graphite, (though clearly that is a reach, but I said it for illustration purposes) that allows us to run a viscosity that stays in the car, and performs at street temp, while adhering, after shut down, to the bearings and cam shafts.
In essence we are making a compromise to keep our cars on the road.
That said, If a 951 owner changes oil really often, and is on a very fresh engine build, they might be able to run an oil viscosity that corresponds to the Docs analysis, of what is needed at start up.
MOST race cars do that.
Street cars have to be more stringent about what is in their oil. It will be there, FAR longer than most people claim.
Therein lies the rub.

I'll bet the Ferrari Doc has someone else change his oil.

pkt1213

I just thought it was a good artical that related to what we were talking about.

When I had my 85 944, it was a daily driver with right at 100k in it and I just ran MaxLife 10-30 the whole time I had it. It didn't burn or use any oil. I know that's not always the case, I had an 88 Integra that got about 100 miles to the quart so I did run a thicker oil in it.

joonas

This is a good article.

If I understood correctly we need:
1. Engines should have a pressure of 10 PSI for every 1,000 RPM of operation, not more, not less.
2. Engines need as much oil flow as possible.
3. The engine is designed to run at 212 F at all external temperatures from Alaska to Florida. Keep oil temperature near 212 F (100 C)

If we experience low oil pressure we just use thicker oil. So we see rise in oil pressure and think all is fine. But there is less oil flow and high oil temps.

Factory manual says that 944 and 944S engines should have aproxx. 4 bar ( 58 psi) oil pressure at 5000 rpm. It is 0,8 bar ( 11,6 PSI) per 1000 rpm.
Manual also says that maximum oil temperature is 140 C ( 284 F ). Manual does not say where though.
In the sump? Where is oil temp sensor located on other sportscars?
I know that some of you have installed the aftermarket oil temp sensors. Do you feel that they show correct numbers?
I plan to use external oil cooler on my 944S to keep oil temps in normal range.

eman930

I read somewhere that in a 944 on the track oil temps can hit 250 degrees F easy. Thats HOT, I want my oil cool, SO I am swapping out the Internal cooler for a external one, Its been kinda a pain cuz I have a 924S and there isnt much room. I believe with a external cooler people have seen a 30 degree drop in oil temps, Plus coolant temps also run cooler

m73m95

240F is "normal" operating temp for most oils, no matter the weight.

250 is alright, but a little hot. Any hotter and its time for an external cooler or, if you already have one, its time for a bigger one.

Anything below 230ish and the oil doesn't protect (flow) correctly at a molecular level.

Thats why its important for your engine to be at normal operating temp before you start hammering it. If your oil is the same as your coolant temp, then the oil isn't lubricating properly.