Peter_S03

...............and I did that for the time I owned it 9 years. dif engine ,,,,,,,,,,,,, 12 qts ,,,,,,,,,,,,,,,,,, 3.2 oil cooled............................

Otto Mechanic

I can't say. You mentioned you hadn't opened the engine, I don't think there'd be any way to measure the rod or thrust bearings without doing that, so how would you know?

Tom R.

Read about Zinc - ZDDP. It was in the synthetic of yesteryear. Now it isn't. The internals need the zinc, just like we need our multivitamins.

Otto Mechanic

That makes sense Tom, and it makes me feel a little better about having used Mobil 1 in the 928 back in the early 90's, since I understand ZDDP was reduced in the synthetics in the late 90's and, as the article I cited reports, that created problems with the older engines during the 00's.

It's always nice to have a theory associated with the observations.

Wisconsin Joe

Well, M1 20w-50 has decent levels of ZDDP.

Tom R.

Still? I've been using Valvoline racing. Recently they changed the label, and added high zinc on the label. I read a few years ago that the whole Mobil 1 line was reformulated to meet the stricter emissions, and zinc was reduced or eliminated.

Peter_S03

OIL/FILTER change done , was not as bad as expected just a long time , while taking off the panel near the oil pan , and letting the oil drain out for a while having a beer, and cleaning the panel , not clean when oil change done last. A college in Fl. has been using M 1 for years. in his S2 which now has 210k has owned it for 17 years, with good results. so I did also. just like in my 84 911 for all 9 years.
Ready for our road trip to Greenville, Ten, on the 27th.

jhowell371

FWIW I read up a bit and seems weights over 40 were not were reduced in Zinc excepting Diesel oil.. I now add a can of STP to my Mobil One at change time just to be on the Zinc safe side. I've used Mobil One for 30 plus years and always felt safe but a while back a Zinc thread made me paranoid about my S2's tappets so I go with STP for added Zinc, figure it can't hurt.

Otto Mechanic

That was the gist of the article I cited; that ZDDP had been cut in half at some point during the late 90's to meet emissions standards and it also mentions Porsche changed their lubrication requirements at the same time, after which all hell broke loose with the older engines. The author says dealerships and certified shops were essentially forced to the change so as not to void warranties, though I can't understand how a 1989 944 S2 would have been effected by factory warranties in 2000 anyway so that seems a bit silly.

Even so, the article does agree with your observation that ZDDP was reduced in Mobil 1 formulations at that time and there is empirical evidence to support the claim using it causes premature wear. I also use Valvoline Racing 20/50.

mel_t_vin

Mobil 1 15w-50 has 1200 ppm P and 1300 ppm Zn...Valvoline VR-1 20w-50 has 1300 ppm P and 1400 ppm Zn.

My girls are particular...Mobil 1 15w-50.

Otto Mechanic

Yes, that was my understanding also, that the Valvoline VR-1 20-50 formulation has a higher zinc content than Mobil 1 even today. From the article I mentioned, it apparently dropped to 650 ppm during the early 00's, which is the alleged source of the problem and may have given Mobil 1 a black eye as a result.

mel_t_vin

True, 100 ppm...not enough to abandon the added benefits of synthetic [lower pour point, lower viscosity at ambient, quicker cold start flow/distribution, anti-coking characteristics]. The question is, with which do you suspect Porsche fills the sumps of their Cups, RSRs, and 919s?

If you want P and Zn, look to Mobil 1 Racing 0w-50...it has 1750 ppm P and 1850 ppm Zn. Unfortunately, that formulation is probably not very user-friendly with catalytic convertors. How much P/Zn is too much? How much P/Zn is adequate?

Otto Mechanic

Well, according to the article, 650 wasn't enough, which is just about all we can tell from those reports.

Tom R.

Now that you have ppm figures and weight analysis I will share what happened a few years ago when I consulted an "expert".

I picked up the 944S from my car partner's garage to get it ready for a tech inspection. I stopped by an Advance Auto and they had the Valvoline racing on clearance for something like $2 a quart. I bought every quart, and made it my business to stop by every Advance between his house and mine. I got a few more.

The Advance by me had a clean 944 in the lot. I parked "the beast" with its rustoleum red fender next to it. Valvoline Racing wasn't on sale. I spoke with the sales clerk/expert who owned the 944. He told me some work he did. I asked him why the other stores had Valvoline on sale. I then asked what he ran. Either 5-20 or 5-30 he said. I cringed, told him it needed 50. He gave me a dirty look. I went to the beast and pulled out the owners manual. Showed him the manual, and asked about zinc. He told me what he was running was fine. I left wondering what kind of discount he was going to get on parts.

neunfünfeins

Completely agree, Allen.
The uninitiated tend to throw all Mobil 1 under the same bus, without bothering to do the research to understand that all Mobil 1 formulations are not the same.

In fact, Mobil 1 15w50 is not really suitable for any of 'today's engines. Why even bother producing it then? And why does it have the higher ZDDP content than 'modern' Mobil 1?
If the answers aren't already obvious, how about in Exxon-Mobil's own words: "Racing and flat tappet applications."

As for how much P/Zn is adequate, long story short, anything over 1000 on stock valve springs is considered good to go.
Back in the day (pre-1997, category SH and older), before the API began systematically limiting/reducing ZDDP levels, they were typically 1200-1400 ppm in all oils.
That's the oil these engines "grew up on", and any higher concentration than that wasn't necessary then... or now.
Full-blown "race oils" with even-higher ZDDP levels are really only necessary for race engines with high valve spring rates to counteract aggressive cam profiles and higher rpms.

That said, oil is religion, and I don't presume to tell anyone they shouldn't use a race oil or boutique oil. Can't hurt anything other than maybe their wallet.
Here's what I will say: Mobil 1 15w50 is on sale right now at Wally World for $22.88 for a 5-quart jug.
Mobil is also running their Spring rebate (until 5/31), which is $12 off per jug (limit two).
Let's see now, that's 10 quarts of 15w50 full synthetic, with "good ol' days" ZDDP levels, for $21.76 plus tax.

So I'm going to do what I've done every Spring and Fall rebate promotion ever since I found out about them.
'Cause hell, for that kind of expenditure I can afford to change oil more frequently to replenish the ZDDP that is naturally consumed in any oil.