ShiftingGears

As a new boy to the 928 engine which oil is best? I saw an ozzie expert talk about 20W50 being the best. What does anyone think? And bearing in mind its a GT engine does this change anything?

Also any opinions on engine flushing as suggested already and best product too as Im def. having the oil pan removed and cleaned out after sitting in storage since 2006. thanks for any guidance chaps.

ShiftyG

worf928

Mobil 1 15w-50
Brad Penn 20w-50
Amsoil Z-Rod 20w-50.

These for three-season use.

If you start the car with engine (oil) temperatures near or below freezing then you’ll need different oils than the above. But, rare is the 928 where that’s true.

Darklands

I use Valvoline VR1 5W50 and my oil consumption in the S2 is way better than before with a 10W40 and has very high ZDDP.
Motul has also products with a lot of ZDDP. The Le Mans ones in the thin can.

Kevin in Atlanta

Valvoline Dino VR1 20W50

Darklands

I think it is important to use an oil that does not tend to foam, especially in the four-valve engines because they pack the heads with oil at high rpm!

worf928

It is also important to use an oil formulated for a street-driven engine and not a “racing” oil unless you want to measure your oil change intervals in single-digit hours instead of thousands of miles.

Strosek Ultra

ZDDP 1800ppm
Designed for hot rods, muscle cars, and classic vehicles produced after 1950, Classic Oil 20W50 uses an additive package that is fortified with high ZDDP (~1,800 ppm) and moly for improved protection for flat tappet or high-lift cams and high-performance engines with tighter tolerances and older elastomer gaskets; the medium detergent level also makes Classic Oil 20W50 an appropriate break-in oil for newly refurbished engines. For the new 2100 Classic Oil 15W50, Motul revised it's legendary 2100 oil to better lubricate and protect naturally aspirated and forced induction engines with flat tappet cams common to the vehicles in the 1970s and beyond.

Mrmerlin

I have been using this exclusively for the last 15 years,
( no loss of viscosity issues , parts appear to be well protected)
My top choice,
Valvoline Dino VR1 20W50,
most FLAPS have it in stock , across the country
about 8.00 a qt today. good ZDDP .

NOTE oil /filter change intervals at every 3500 miles

NOTE on some cars putting 5k miles on them could take 3 to 4 years

ROG100

I use 0W - 40 but my lifters seem to clack a lot.

Babado

Amsoil Zrod 20w50 going in my new to me 86.5 , following the original previous owners oil use.
Bruce & Sean Buchanan the Australian 928 experts recommend 20w50 too!

https://rennlist.com/forums/928-forum/1335715-bruce-and-sean-buchanan-buchanan-automotive-on-oil-tt-and-tbf.html

khalloudy

I just ordered Porsche Classic 10W-50… not sure if anyone has tried it yet, but will update once I do my oil change on the stat.

ALKada

Naughty man….

zaevor2000

We have an awesome resource here in the 928 section.

I downloaded Doug Hillary's pdf on lubricants for the 928

VISCOSITY (SAE - “THICKNESS” GRADING according to SAEJ300)
Oil viscosity grading uses the Society of Automotive Engineer’s (SAE) J300 system which has been around for many decades. For engine oils it commences at SAE 0W (cold start) and ends at SAE 60.
The viscosity grade is shown as a single number for mono-grade oils (eg. SAE30) and by using two numbers for multigrade oils (eg. SAE 15W-40).
The viscosity is always given at two points, 40C and 100C. For Porsche 928’s a viscosity rating called “High Temperature High Shear” (HTHS) which is measured at 150C is critical – it must be at/above 3.5cP in our engines when used normally. Personally I prefer a lubricant at around 4cP
Multi-grades grade lubricants have a lower cold start rating and an upper viscosity limit. As an example a SAE 15W-40 lubricant must fit between 12.5cSt and 16.3cSt at 100C and have a High Temperature High Shear (HTHS) viscosity at 150C of 3.7cP
The 15W (cold start) rating indicates that it must have a maximum low temperature pumping viscosity of 60000 cP at -25C
NOTE: The ?W rating applies only to the cold start/flow characteristics of the lubricant. Therefore in general terms 0W-40, 5W-40 and 15W-40 lubricants will all have relatively similar viscosities at 100C but will flow quite differently at lower temperatures – they may have different HTHS viscosities (at 150C) too
It was recognised by ACEA in 1996 that an engine lubricant’s HTHS viscosity measured at 150C has a significant influence on both engine and oil durability. Porsche uses this as a baseline for their Approval system
The correct viscosity for YOUR CAR AND CLIMATE is extremely important and it is shown in your Handbook. Whilst this has long been outdated by Porsche TSBs this is the prime guide if you chose to use non Approved oils. After all the Porsche Engineers knew and still know the 928 engine best!
As an example, a non Approved 15W-40 viscosity multigrade HDEO is suitable in a 928 at down to -15C. The 15W bears no relationship to the -15C temperature figure it is a cold start lubricant rating. A 15W-40 viscosity HDEO is suitable in a 928 for temperatures up to 40C, and at higher temperatures for short periods. The 15W-40 viscosity range therefore embraces both these extremes very well for most owners

RennHarry

Isn't this the topic "most likely to start a fight"???
Cheers

hacker-pschorr

A number of us followed Doug's advice back in the day (I think it was close to 20 years ago) and things didn't work out so well. Myself and several others all had the same experience. On hot days the 40wt simply couldn't hold oil pressure, first the gauge would drop to an uncomfortable level then the lifters would start to tick. This happened to 16V and 32V 928's. I'm in Wisconsin and AO had the same experience in Michigan, so it's not just a hot climate situation. But IIRC both of us tried this experiment in July.