50 pages of technical data! My brain hurts!

I have a 1987 Carrera Cabriolet that does almost no mileage per year (50k from new).

What oils would you experts recommend?

I'm in England.

The above post for those who are interested, is a bit out of date. It is a reader's digest version of Mr. Orlee's "How Much ZDP is Enough?", from the Powertrain and Fluid Systems Conference, presented October 2004, from when the SM and CJ-4 specifications were being discussed.

I don't think because this was written a couple of years ago it is irrelevant? We are merely talking about ZDDP levels on this thread and whether testing was done last week or 5 years ago, the results would still be credible.

Yes, we already know there are two test sequences specifically for evaluating wear of both flat tappet and overhead cam engines for the API SM specification (as well as the CJ-4 specification for the IVA test sequence).

If these tests are done in a proper controlled environment, shouldn't we trust their conclusions more than gossip spread on the internet?

As mentioned somewhere in these 50 pages, the spring pressures over the nose are very different in both pushrod and overhead cam Porsche engines, significantly more than the production engines used in the aforementioned IIIG and IVA test sequences. But that is not the whole of it...

On the contrary, the ramp rates and nose pressures on modern engines exceed the levels on the 911 engines we are talking about. Modern engines are designed to extract more horsepower from less cubic capacity, they do this with higher compression, more valve lift and more rpms. Many VTEC motors use flat tappet style followers as shown in my previous image (Honda).

Furthermore, look at the test parameters for coolant and head temperatures.

http://www.swri.org/4org/d08/GasTest...st/default.htm

An aircooled engine operates at much higher temperatures and camshaft profiles typically have higher ramp rates, all of which contribute to the problem.

The limits for wear are ridiculously high, compared to requirements set forth by the ACEA. Right from the IVA sequence:

Pass limit includes average cam wear of 120 μm maximum for API SL and ILSAC GF-3 and 90 μm maximum for API SM and ILSAC GF-4.

The IIIG sequence is a bit better, with a limit of 60 μm, and is run at higher oil temperatures and rpms to evaluate more deposits and varnish formation in engines.

http://www.swri.org/4ORG/D08/GasTest...st/default.htm

I would argue that the test parameters that were chosen were not by accident, ALL production motors operate at higher temperatures than the test parameters. Modern engines are being run hotter than in the past to extract higher fuel efficiencies from the motors.
However I would hazard a guess that the reason these very parameters are chosen is to exaggerate the wear on these parts so that good quantifiable data is obtained.
The equipment they use for wear measurements may only have a resolution of +/-5 microns or so, now imagine if they ran their tests at an optimum point for minimizing wear, they might see 1-3 microns wear in their 90 minute test. How could they possible measure this with any degree of certainty? they couldn't. They purposefully run the test to get extreme wear rates so that they can get good data.
As far as varnish formation, that is another completely different topic from the ZDDP we are talking about here. I haven't seen an engine gunked up with varnish for 15-20 years.

But again, a GM 3600 V6 is no Porsche engine and quite frankly was one of the worse engines IMHO that GM ever produced.

Compared to the ACEA A3/B3 which has a cap of 15 μm for max combined and 10 μm for any single occurance.



With all due respect for Mr. Olree, just as with the myth he is trying to debunk, not all engines are created equal nor can you blanket one single test to account for every engine and situation.

Whether this GM engine is good or bad is completely irrelevant for this discussion, I would argue that its good that the engine is considered poor, it would show that even with a poor engine that the new oil formulations are working as they should.
We are not talking about every engine under every condition, we are talking specifically about one thing and one area under question and that is tappet wear?

The definition of acceptable wear and what is considered a failure is the grey area in which we reside with performance aircooled engines. The failures (including high wear not resulting in catastrophic failure as well) are well documented with builders like Jerry Wood, Steve Weiner, and many others again aforementioned in this thread.

I give about one hour talks on the subject from time to time, but honestly, that doesn't scratch the surface.

I have and have studied every SAE publication from the 60s forward on lubricants which took me months to pour through, helping to make sense of everything, including the fact that the detergency of oil also plays a huge part in how well an oil protects and how much Zn and P is required in an oil. Then you have viscosity and the direct relationship to the HTHS viscosity and wear in both boundry, hydrodynamic, or mixed lubrication regimes. Yes, this is a very complicated subject and it's very easy to oversimplify with generalizations. There is no easy answer.

Yes oil formulation is a complex business no doubt and that is exactly why laboratories need to run these standardized tests to establish cause and affect. Without them, we all run around panicing over something that may or may not be a problem. In my searching on the net I've found it rather amusing that various forums cross reference each other on this topic, as if to legitimize each other.

Yes, all the research that has been conducted over the last 50+ years is useful. Obviously, these tests do have their place and SM and CJ-4 rated oils also have their place, in modern engines, or otherwise there would be a whole lot of cars suffering from lubricant related problems. Some of these test sequences are out of date and the engines used to perform the tests are not indicative of the engines we are discussing.

I am not here to discuss modern engines and the best lubricants for them. Yes, Mobil 1 0w40 will work in a new water-cooled Porsche (although there are better approved oils out there). This thread is how modern lubricants may not necessarily be the best choice for some older (performance) vehicles, i.e. Porsche.

My question is simple...

If you use a good oil (Castrol Classic Car, Mobil 1, Roto Dino)... and change your oil every 2k-3k miles... are they not ok?

Seems to me to be abit much to be paying to have oil shipped in from hundreds of miles away.

83 SC

Reader's Digest version of the last 50 pages, and after discussing this with Charles over the past couple of months, if you want the best:

For air cooled 911s:
Synthetic: Motul 300v Competition 15w50, or Mobil 1 V-Twin 20w50
Non synthetic: Brad-Penn 20w50 or Swepco 306

For water cooled 911s:
Synthetic: Motul 300v Power 5W40; 2nd choice 50/50 blend of Mobil 1 MX4T 10w40 with Mobil1 0w40(or straight MX4T)

ok, but why do we want to use heavy oil in air cooled porsche's?
Lighter oil = better lubrication and better flow, and better flow means better cooling.

I'm planing to use 5w40 oil in my porsche. Would that be so bad?

Beg to differ, but I'm more interested in tests based on two valve engines. Multi-valve engines, like the V-TEC, have lower mass valves and lower spring pressures and no matter what the ramp rates are, those two factors weigh heavier. Run tests on flat tappet Porsches, flat tappet SB and LB Chevy's and I'll become a believer. Until then, I've seen too many high performance 2 valve engines with premature wear, sculling to be swayed by that GM thesis.

The heavier weight oil has higher HTHS (high temp, high shear) values, with looser build tolerances, is what Porsche originally spec'd for the air cooled motors. Water cooled motors with more stable temp characteristics and variocam require the lower viscosity for proper cam operation at the expense of HTHS protection.

thank you for your answer ;)

What weight is optimal for 2.4T? Would 5w50 be ok?

There must be some merits of Motul 300V as it's also the oil one Porsche garage here designated for their cutomers and I did see a certificate of approval by Porsche there for the use of Motul 300V.

Most of us use either 15W-40 or 20W-50 oils. I would think that anything under 15W is to thin.

Hi,

I am no expert by any stretch - I just do my research and make my choice, and I use Halfords own-brand Part Synthetic 15W40. Its a high quality oil, being ACEA A3/B3, and I like the fact it is semi-synthetic (I feel it might give you the best of both worlds of sythetic and mineral). I have also used Motul Synergy 6100 (or 8100, as I think it is now) 15W50, which is also semi-synthetic.

Personally I don't really believe in this "classic" 20W50 stuff - maybe for a 1950s car, but not for an 80s porsche, and I think 20W50 would be too thick for our colder climates.

The Motul semi-syn 15w50 is next on my list to test, as it's easier to find in Europe and would make a great choice I would think. Having an ACEA A3/B3 approval is a plus for sure. Means a lot more to me than an API rating for sure. Overall, I'm very pleased with Motul's products as a whole, albeit they are very expensive in the US.

The Brad Penn 20w50 is good to 15-20F, which for most Porsche owners, is acceptable. In colder climates, the Swepco 306 15w40 will get you down to the 0-5F range roughly before it's time to consider something thinner.

Brad Penn Drip Tray test
 

Greeting from Sydney
John N suggested I post my story about my 90 964 C4 that always used Mobil1 for the last 10years and starting to leak oil from an oil change to 0W40 it was so bad i reverted back to Mobil1 15W50 which reduced this problem although not enough. Then after much talk, Brad Penn had just been launched on the market here so changed to 20W50 Brad Penn 2 weeks ago. It seems hard to believe after the car being driven for the first 7 hours on fast highways and city driving at high ambient temperatures with Brad Penn on board still with a couple of litres of Mobil1 mixed in,

Currently have a couple of drops on the drip now and well within an acceptable limit. Now I can visit my friends again without dumping on there driveways. I noticed before Mobil1’s 15W50's oil pressure at hot idle is about 1-1.5bar now its up over 2bar + although the motor runs slightly hotter than before although more silent, the low oil pressure warning light no longer flickers ON that would freak me out in bad traffic any more, that's a relief. 2 Porsche workshops told me engine out time one saying cylinders 1 & 3 cylinder base o-rings were leaking the other said the crankcase through bolts were leaking so I'm thrilled with the results as 2 weeks after these photo's were taken there is nearly nothing in the drip tray at all.
http://forums.pelicanparts.com/uploa...1225927548.jpg
http://forums.pelicanparts.com/uploa...1225927571.jpg
http://forums.pelicanparts.com/uploa...1225927595.jpg
http://forums.pelicanparts.com/uploa...1225927620.jpg

Anybody want to look at this virgin oil sample of Redline 5w-30?
http://users.forthnet.gr/ath/mesastoura/RL_5W30_6747_AN_(2=07).pdf

Anyone think this could be a good winter oil.

At near $11 a QT., seems a little pricey.

I used redline in my other cars with excellent results but was nervous to use it in an aircooled.

If anyone has the time to give their opinion that would be great!

BTW, this PDF is from BITOG on the VOA forum, this is not my sample, just taken from there.

FWIW I ran the Redline 20W-15 in my 911 track car. I changed it out after 1000 miles and did an analysis. Based on the high iron numbers Blackstone recommended 500 mile oil changes. I am now running Brad Penn, and will do another 1000 mile analysis after this weekend's track event for comparison. I did note that temperatures were about 10 degrees cooler than with Brad Penn.

It's funny you mention the iron. Reading some Redline Oil Analysis after some mileage, it seemed most cars had a very high iron reading. Eventually after some more mileage and continued use the iron went down, I don't know if it was cleaning or wear.

I too use Brad Penn 20w-50 and will stick with it buy will have an analysis next year.

I also don't know if they have been changing their formulation since I saw the high zinc on the Redline 5w-30 figured it was worth a look.

Another non-rotating, non roller tappet example
 

I stumbled across this engine build online, it is a 996TT engine. If you look at the pic showing the bucket cam follower closely you will notice a few things, one is that is has "ears" on the side that stop it from rotating. You can also notice how little area the camshaft has to operate on the follower. (it is a variocam so it switches between the outer and inner).
Considering how many cam followers are out there that use the same basic principle of operation as ours I really believe any issues seen with degrading cam shafts and followers is due to manufacturing issues when the parts were made, there is no magic in older oils.
http://www.imagineauto.com/996motor/tappets.jpg

Here is the camshaft in place, notice how narrow the lobes are.

http://www.imagineauto.com/996motor/cam%20set.jpg

Bart_dood,

You can believe what you like.

Me, I lean on the experience of others. Check Posts 342 to 346 of this thread.

Post 346 is a direct response to post 342. The way I see it, Mr Weiner has torn down many more engines than I ever will and they have seen a variety of services. Why would he be making these observations? Care to share some details that are unknown to Mr Weiner? These posts state:

Charles, such irony in your comments...If you look in the Advertiser index in Panorama, Mobil is not listed. Interestingly, your company is...While Mobil may have a relationship with Porsche, it is not abundantly clear what their relationship is with the PCA...All that said, the Panorama Article references some of your efforts, so it can't be all that bad/incorrect, right?

If you haven't read the article, it does suggest Swepco & Rotella products for "mineral" based oil options. There is also a reference to an update in Valvoline VR-1 / 20w50 to address zinc concerns.