Correct oil for 1980 3.0 911SC

[LankIXXI]

Always used Mobile 1, 10W 40, last change switched to Valvoline extended use 10W 40, which I'm fairly happy with but keep reading/hearing about Zinc and Phosphorus? There are so many brands but in the last discussion group kept talking about Brad Penn as the main topic but enough stuff thrown in to confuse me; as in Mobile 1 V oil, Shell Rotella?, but diesel oils were recommended for air cooled Porsches, can this be right? What about Redline synthetic oil or Motul?
I'll save my confusion about oil filters until later.

[Joe Bob]

VR1.....there is a LONG THREAD on the Ultimate oil. Do a search....

[Ronnie's.930]

Motul 300v4t 15w50 . . . Brad Penn can't carry that oil's jock.

[Bob Kontak]

Originally Posted by LankIXXI

Always used Mobile 1, 10W 40

20W 50. Pick your poison.

NOT 10W 40.

[Jack Stands]

Porsche would like you to use their own branded oil (though won't say who makes it for them). Many threads have been written on oils (search as you like), but many folks are using Brad Penn (basically the old Kendall GT), Joe Gibbs, or other oils that are being formulated for 'vintage' cars. The old Shell Rotella has been re formulated and may no longer be appropriate.

It's a constant battle!

[beren]

How many miles/year are you putting on your car? I put so few (4k/year) that it probably does not matter. I've used both VR1 and M1. I prefer M1 because it is easier to get. I've got 133K on my 911.

Many threads on oil - fun reading with no clear answers.

[tirwin]

I run Mobil1 15w50. It's the one that says "race proven" on the label. I have downloaded the spec sheet from Mobil1's website and it exceeds the recommended level of ZDDP for flat tappet applications.

I was at O'Reilly this morning and the guy behind the counter said that it will be on sale for $5.99/qt soon. If it goes down to that price I will buy a few cases!

[sugarwood]

First 3.2 oil change. Couple of questions.

[Bill Verburg]

Originally Posted by LankIXXI

Always used Mobile 1, 10W 40, last change switched to Valvoline extended use 10W 40, which I'm fairly happy with but keep reading/hearing about Zinc and Phosphorus? There are so many brands but in the last discussion group kept talking about Brad Penn as the main topic but enough stuff thrown in to confuse me; as in Mobile 1 V oil, Shell Rotella?, but diesel oils were recommended for air cooled Porsches, can this be right? What about Redline synthetic oil or Motul?
I'll save my confusion about oil filters until later.

break in oil needs high ZDDP in the 1400ppm + range, but above ~2000ppm long term wear problems arise

historical ZDDP levels can be informative ie before the current ZDDP tempest

M1 API SH 15w-50 circa '93-96 1095ppm P, 1427ppm Zn(I don't have the specs for previous years but they would have been in line w/ the SH specs)

M1 API SN/SM current 1200ppm P, 1300ppm Zn

M1 API SJ 20w-50 1600 ppm P, 1700PPM Zn great break in oil!!

get the weights from your owners manuals
my '76 C3 wanted 30w summer oil, my 993 15w-50, Sometime after '76 15w-50 and 20w-50 became the normally recommended and used oil in 911

The current ZDDP controversy was caused by US govt mandates for fuel economy and emissions life, all new cars are designed for lightweight oils w/ reduced ZDDP, these oils are identifiable by the starburst labels on the cans, the heavier wt oils like 15w-50 are not included in the ZDDP issue though some reduction in ZDDP may have taken place. There will be less of an issue w/ RoW oils like Motul.

Do some research, some oil companies publish the ZDDP specs others do not.

I'd only use oil from a company that publishes

M1 and Brad Penn publish, see above for current M1 specs

[ganun]

Few mention the latest factory recomendation, (wonder why?) which is early cars to the 2.7, 20w-50, 3.0 and largerr aircooled, 10w-60, .....I have used 20w-60 , in so Florida a 20w would do for cold weather performance.

[tirwin]

I saw on TV recently (one of the car shows I watch) that one of the reasons for the general movement to lower ZDDP was because ZDDP could make it's way into exhaust gas where it collects in the cat and shortens the cat lifespan.

Any truth to this or myth?

[spyerx]

Originally Posted by tirwin

I run Mobil1 15w50. It's the one that says "race proven" on the label. I have downloaded the spec sheet from Mobil1's website and it exceeds the recommended level of ZDDP for flat tappet applications.

I was at O'Reilly this morning and the guy behind the counter said that it will be on sale for $5.99/qt soon. If it goes down to that price I will buy a few cases!

Wally world sells the M1 15w-50 (good stuff) in the 5qt containers for ~$25 almost all the time.... makes it worth the adventure.

[tirwin]

Originally Posted by spyerx

Wally world sells the M1 15w-50 (good stuff) in the 5qt containers for ~$25 almost all the time.... makes it worth the adventure.

It used to be available here in the 5qt but I haven't seen it in a long time. I have caught a sale at Amazon once or twice too.

[Bill Verburg]

Originally Posted by tirwin

I saw on TV recently (one of the car shows I watch) that one of the reasons for the general movement to lower ZDDP was because ZDDP could make it's way into exhaust gas where it collects in the cat and shortens the cat lifespan.

Any truth to this or myth?

The current ZDDP controversy was caused by US govt mandates for fuel economy and emissions life, all new cars are designed for lightweight oils w/ reduced ZDDP, these oils are identifiable by the starburst labels on the cans, the heavier wt oils like 15w-50 are not included in the ZDDP issue though some reduction in ZDDP may have taken place. There will be less of an issue w/ RoW oils like Motul.

ZDDP degrades catalytic functionality

oils w/ this symbol, are low ZDDP and low viscosity, ie made for cat life and fuel economy, not for flat tappet cams

[J-Mac]

Does Swepco 306 get an honorable mention anymore in the oil discussions?

[tirwin]

Thanks, Bill. I think the new info to me was that the ZDDP itself shortens the cat life. Never knew anything more than the very general emissions life statement.