Mobil 1 15w-50 synthetic (order it online http://thelubricantstore.com/mobil-1-15w-50-6x1qt.html), with a small amount of Torco ZEP.

 

Brad Penn - mechanic friend won't use anything else. He previously used valvoline VR1 until it was changed due to the EPA laws.

 

In the inevitability my sophomoric post gets deleted as promised, here is what I plan to use...

Valvoline VR1 20W-50. Because I don't race and plan to change every 3K or 6 months anyway, it'll be good enough. Plus its affordable and readily available at my local O'Reilly's.

 

I use M1 15w-50. I've used it since I bought my '91 almost 20 years ago. When I pulled the cam covers in 2008 at ~80k to replace the gaskets there was no cam pitting, the lifters looked great and no dyno-oil varnish.

I had enough on the shelf that I missed the year or two when the ZDDP was low (if that's more than legend.)

I have never had oil pressure issues - but, I do disconnect the LH and crank until I see oil pressure whenever it sits for more than a month or so.

For client's 928's I'm fine with M1, Brad Penn, Amsol Z-Rod and Castrol GTX as long as it's a 10-20w-50 weight oil and is known to have > 1000 ppm ZDDP.

 

A synthetic blend to boot.
The following are typical properties on Mystik JT-8 15W-50; Phosphorus 1050 ppm Zinc 1280 ppm Magnesium 1060 ppm Calcium 1220 ppm

 

Total Classic Racing 20W50. Why, because the weight is appropriate for our hot Arizona climate and has higher levels of zinc.

 

Castrol synthetic 10W60, because Roger said so

 

Anyone keeping score?

 

I tallied the following - see below. Not sure the best way to do this, but if a response mentions the usage of more than one brand oil, e.g. Jim / jcorenman's response, I counted each of Jim's favorable oil brands in the list. In other words, he got more than one vote (I'm from Chicago, so that's a normal thing).

What I have concluded from this thread so far is that the good news is, there are a number of suitable oils for our 928s. If Greg Brown says Brad Penn is good, and if Jim Corenman has successfully used Mobil 1, Amsoil, Brad Penn and Torco, and so on, then the tally count is not as important to me as the reasons why each are using the oils in their sharks.

Mobil 1 14
Brad Penn 10
Castrol Syntec 7
Royal Purple 7
Amsoil 5
Valvoline VR-1 5
Torco TR-1 3
Rotella T3 2
Shell Helix 2
Kendall GT-1 1
Lubrication Engineers 1
Millers CFS 1
Mystik 1
Porsche Classic 1
Total Classic Rading 1
Lubrigard 1

 

in my '78 5-speed with 60,350 miles on it, I use whatever came with the car from the factory. never changed it. I misread 6,000 miles as 60,000 miles and I am glad I saw this post. from what I understand 60,000 mile is too many miles on the oil.








...Brad Penn 20-w50




.

 

Amsoil 15-50 racing oil because it keeps oil pressure up at 5 bar at 260F temps on the track and after 8 years of racing, the engine internals were spotless when taken apart. But, mainly due to the other oils having major thermal break down when used under track conditions. (specifically mobil 1 and Valvoline racing oil)

 

I use liqui moly 10w60, before i used royal purple 20w50 but here in Italy is rare to find and costly, always more than 180 us dollars for 8 quarts. Liqui moly seems to be the best 10w60 on italian/european market for its specs and availability, holds pressure from 3 bars on at idle even during this Hot summer (35-38C), it can stand the stress during track days .internal are really clean.it is very like royal purple( but a bit better for pressure and oil consumption). Tried castrol rs 10w60:good performance the first month/400km I put it in the engine, then a big drop in pressure, 2 at idle and not more than 4 at 2500 rpm... plus noisy valve lifters after cold start.never again.

 

Liqui Moly was NLA in Spain where I lived. Switched to Castrol, very happy.

 

I bought 10 liters in germany, 73 euro +15 for delivery in Italy...

 

Shell Rotella T6 5W40 because it has the right ZDDP levels and oil pressure is always excellent regardless of temperature. I also used it in my 911SC and found that oil pressure was also good with lower oil temperature compared to temperature when running 20W50.

Hugo.