ShawnSmith

My opinion:

Either use whatever weight-appropriate bargain brand you like of dino oil, and change it every 3k miles like everyone did in the 1950's.

or

Use the best synthetic you can locate and send it out for analysis so you actually know when it needs replacing.

dr bob

In a year of driving, my M-1 gets a little darker than when it was put in, and uses about 1/4" on the dipstick give-or-take. I bought a bunch of the 'old' flavor M-1 and I'm just about through it. One more year to go on my stash.

If Mark says I can use Wesson Oil for my street car, I'll start looking for deals on it. How much ZDDP should the Wesson have, and is it available as a multi-grade for the cold winters we have here?

blown 87

Call me free with my money, but I change mine every 3,000 miles, and don't care if it needs it or not.

If I am wrong for changing to early, what have I really lost?
If folks that change the oil every 15,000 miles are wrong, what have they lost?

BIMMERMIKE

What is Doug Hilarys' opinion?
Aussie guy I think, seemed to have expert advise on oil grade and brand for our 928s.

hacker-pschorr

I've used M1, Castrol, Royal Purple, Amsoil, and Valvoline in my Audi 5-cylinder. All of them turned black pretty quick (less than 1,000 miles). All original engine with over 170k miles. I'm not worried about it, on cold morning the lifters tick. Oil is changed every 3k - 5k.

I never said anyone was right or wrong, just tossed an idea on the table. Simply a suggestion that will not hurt anything.

To this date I have never sent in an oil sample of my own. I plan on starting this year since three of my cars didn't even reach 2k in 2008. I have a hard time believing the 9 quarts of 12 month old oil is somehow "bad". I'll find out soon enough and I'll post the results. I also tear open every oil filter.

I have never gone more than 5k miles before an oil change with my Audi, never 3k with my other cars.

He suggested Delvac 5w-40 which I tried. My oil pressure fell off the gauge and my lifters were singing (which they never did prior) at idle. So I went back to 20w-50.
This simply proved what works for one 928 is not the best idea in another.

One of these days I should install an oil cooler in my 81. It didn't even come with the factory cooler in the radiator.

brianrheffron

Thanks for all the good information. At the last sevice an 928 independent specialist put in Castrol Magnatech 10W40 which is recommended by Castrol for the 928 and approved by Porsche. From the feedback on my original post this may not be such a good choice being a very modern oil rated APPI SM.
Having read the link to "Cam-shield" plus all manner of threads when I searched ZDDP my conclusion is that I will go with a full synthetic oil, probably 10W40 to suit the mild Scottish climate (never to hot or too cold), but also use an additive like Cam-shield to be sure the cams and followers get the right degree of protection. Does this seem like a sensible approach.

SteveG

And you are saying he is an unbiased source?????



Actually, you didn't say he was unbiased.

blown 87

For years he recommended oils to me other than Valvoline, I worked with him for many years, plus he is a friend.

He does not feel any loyalty to Valvoline for more than a few reasons.

Obviously I could be wrong, but I would be very surprised if he was biased when talking to me.

SharkSkin

Oil is not "just oil", Wesson comments notwithstanding. I had been running Valvoline 20-50 dino, then on one occasion couldn't find it locally. I went to an independent shop that talked me into getting CarQuest branded oil, he showed me the MSDS from Valvoline and assured me it was the same stuff. It wasn't. I lost 1-1/2 to 2 bar at idle. I changed it ASAP.

To the OP, it's not just about how much power the engine makes. You want an oil that will hold up when hot, not foam up, and will protect the flat tappets and soft rod bearings.

blown 87

I worked for Valvoline for many years, the last few as a blender, not sure about CarQuest, but the Napa oil came out of the same tank as the cheapo Valvoline, it used to be called "All Climate" but that was years ago.

I used to blend about 250,000 gallons a week of All Climate in just 10w40.
No telling how many millions of gallons of motor oil I have made.

Valvoline does a huge amount of private label products, but you have to go to the Racing oils to get the good stuff from them, they do not private label it, or they did not while I was there.

andy-gts

here is a posted pdf by andrew with alot of cool facts to help make decisions

dprantl

Looks like the Mobil 1 EP 15W-50 is still good even with the SM rating. That's what I have been using recently.

EDIT: I just went down to Walmart and they don't have Mobil 1 EP 15W-50 anymore, only 10W-30

Dan
'91 928GT S/C 475hp/460lb.ft

SharkSkin

What I had been using was a racing variant. Anyway, I'm moving to a completely different brand, not on the list above -- will see how it behaves.

SteveG

And this was when you were also working for Valvoline? So you BOTH worked for Valvoline.

I'm just ragging you. It might all be true. It might.

GregBBRD

Please....no!