Crackhead944S

P,

One should at least be able to verify that these revisions took place, which I would assume differ from an '83's owner's manual. I will once I get my heap running properly again, so expect me to post results in '08

heinrich

Dudes ... I used to be VERY skeptical and actually I mistreated Doug pretty badly. HOWEVER i have concluded over the past years that Doug knows what he is talking about.

Jim bailey - 928 International

The original thread which started Doug's reporting of his oil analysis for his 928 had a number of people including one , largely self proclaimed "EXPERT" stating that oil needed to be changed much more often than the interval stated in the manuals. As Doug reported that his oil was nearly as good as new at the end of each test, far exceeding minimum standards, but he changed it because Porsche said too, many on this forum asked what oil exactly he was using. Dougs repeated analysis while not statistically significant were to simply CONFIRM what Porsche recommended for service intervals. Perhaps worth noting that Porsche for many many years put the Shell Oil sticker on all the air cleaners as an implied endorsement and as a result I am sure many Porsche purests continued to use Shell oil. It would not surprise me if Shell GAVE Porsche the oil for free. Doug's reports help counter the urban myth that changing oil every 2,000/3,000 miles is being GOOD to your car !

SharkSkin

FWIW, I doubt you could even lay your hands on a case(or even a quart) of the reccomended SE/SF oil at a typical retail outlet. Oil technology has come a long way in 20 years. My last oil change was with oil rated SM.

As for Doug's credentials.... He runs a fleet of trucks, probably has many billions of miles logged with detailed oil analysis. I trust his application of his decades of experience to his study on 928 oiling. Did you look at the other 9 oil condition reports?

ErnestSw

P
Read my last post. If you're not comfortable with Doug's experience as an oil engineer and as a fleet owner continue to follow the instructions given you by Porsche. If you want definitive proof with legal standing you're in the wrong place.

Bill Ball

I got terribly low idle oil pressure with Castrol Syntec 5W40 (or was it 15W40? - regardless it was 40 hot) at the end of a high-speed open road race. The warning light came on when I came to a stop, so I shut the engine down immediately and let it cool off for a while before restarting. No particular issues after that, but I wasn't comfortable seeing the warning light at all (I think less than 1 bar).

So, I went back to M1 15W50. Never seen M1 5W50. The re-opening of this thread today caused me to go back and review it.

I see some ambivalence in the comments about M1 15W50
- not approved (5W50 is - but I have never seen that for sale)
- too high viscosity cold can cause wear (hence go 5W)
- but M1 5W50 has excellent flow characteristics
- "Remember that M1 15w-50 is a very high quality product that is suitable for annual or 12k miles oil change intervals when used in the correct ambient range - from -15C to 40C+"

There seems to be most interest in going 5W/40 Delvac or similar. I'm concerned about 40 in a hot motor, at least idling. Doug made some mention of Castrol 10W60 for high-speed racing. Any experience with that?

So, I think I need 50, at least, for open road racing and don't plan to switch back to 40. Would like to find M1 5W50 and might consider Castrol 10W60 if it is around.

BC

Bill - the facts have many layers here and Doug has been extremely helpful to me in PMs - the issue being that I am in San Diego. YOu are in NorCal, which can get quite cold.

If I start my car, you can sure as hell bet the temp is never below 55 degrees. My point is that people need to think about what tempatures they start and run thier cars in year round. My decision process is MUCH more simple then thosein North Dakota, or in "P"s case (no name, no identification at all - even addiction meetings use at least thier first names) in TN, they get really cold there. If he is in the mountains, I would expect 15 degrees or a bit higher on some cold winter mornings. He needs to think about different oils for different times of the year.

I don't, and many people in warmer year round climates do not.

Call it 50-100 degrees, but usually 50-80. A very small range of starting temps. And after 5 minutes of run time, the oil is warm. So the lower number is now defunct, as I read Doug's comments. I used 15-50 mobile. Its just too warm here for me to go lower, and the 85 was splashing it up into the breathers WAY too much with the 5-40 delvac. I run these cars too hard (even on the street, let alone the track when I get there finally) to deal with the possible viscocity issues of a thinner oil. I understand the advances in technology have allowed Porsche to suggest the 0-30 or whatever for the new cars.

SOme say thats a horrible oil and they up it a bit, some say "don't go against porsche".

Well, Porsche is no longer covering thier cars for much track use warantee issues, so if they know they don't have to pay for work, then why worry about what oil they suggest. Race cars that only see warm temps and racing duty use single weight oils. 40s, 50s, as I recall.

Oh, and thrust bearing wear is major issue on 996 engines. Same for earlier 911 engines as well. People want to say its not possile, but there are alot of flaws in these engine designs, and I think experts would say that a thicker oil may prolong the lif of parts of the engine that may be too stressed.

I've digressed. Mark Kibort has never had a rod bearing go. He uses Amsoil exclusively.

heinrich

SHUT UP SUNSHINE BOY

BC

You're welcome any time. Played tennis on January 22nd outside. It was 80 on the court.

heinrich

Where's the middle finger icon ... on that day I was sloshing through mud to get to my garage.

heinrich

Btw Brendan i would and WILL take you up as soon as I can afford it timewise and otherwise .. thank you Dude

BC

I'll need somebody to drive while I tune the EFI with the laptop when the 78 is done.

Bill Ball

Yeah, Amsoil. I just can't get behind boutique oil that may be no better than general commercial brands. Amsoil just reminds me too much of Slick50. I know people I respect love it, but I just haven't seen real field tests or true independent lab test that justify the extra cost. The evidence is anecdotal.

Good points about ambient temp. My car overnights in the attached garage, so temps are moderated almost to in-house temp. I'd like to find 5W50. That should cover the occasional real cold start.

Jim bailey - 928 International

Brendan you are pushing your luck , good thing the North Westerners tend to be more suicidal than homicidal

BC

No Argument there on Amsoil. Very little info. As Doug says, Amsoil and other smaller carriers do not do the same testing that Mobil does. But I do read mark's Comments about oil pressure at idle between the two. You saw the same thing, but with different oil. Its a point of info to be aware of, as you stated.