djantlive

I have been using 20-50 dino juice on my 1990 944 s2 since new. This past week, I switched to 5w40 synthetic for the first time. I noticed a 2mpg improvement (26.5mpg) and the engine runs smoother on the highway, engine temp is slightly lower as well.

I hope sync doesn't leak and I will be monitoring. But so far, I see a noticeable improvement!

MAGK944

Oh yippee, an oil thread!

JET951

The below is a post I put up on the 964 Turbo list a couple of years ago , read it carefully I mention the twin cam 944/968/928 in this post , you're timing chain tensioner needs decent oil pressure along with No 2 conrod bearing ( big problem on the 944 series at high RPM with a 5w-40 oil )& then you're high loaded flat tappet designed cams must have high oil film strength & 5w-40 will not give that protection , meaning cam lobe wear


All the oils viscosities & the very important corresponding "Oil Film Strength "engine oils you guy's are discussing are fine , be it 15w-50 or ( better still ) 20w-50 , the reason I mentioned that is because the 3.2 911 , 3.3 911 Turbo , 964 , 964 Turbo, 993 & 993 Turbo( and the front engined Porsche's ) had to go through the silly season of when the low viscosity so called synthetic engine oils were advertised heavily ( be it USA , Europe , Australia , Japan ) from the mid to late 1980's onwards

And of-course humans being human , they were more than happy to spend twice / three times as much on a "new type" of anything , could be a cell phone but in this case it was an engine oil and the spin had the words Synthetic or better still fully synthetic & it didn't seem to matter much that the viscosity they had been sold was often way too low for the air cooled ( high core temp ) 911 engines & enter the next 25 - 30 years of multiple ( new to them 2nd / 3rd /4th ) owners who couldn't wait to install a 5w-40 ( example only ) when it should of been a 15w-50 or 20w-50 like it stated in the owners manual & we couldn't go through a single summer he in Sydney Australia without another 911/944/928 owner dropping by our workshop ( Saturday mornings were super common ) with the Engine Oil Pressure Warning light glowing brightly at idle , meaning lack of oil pressure at idle & the corresponding low oil pressure at any given RPM than what it should be & when we drained the 5w-40 & installed the correct 20w-50 & the oil pressure warning never reappeared the owners of these 911's or 944 or 928 were stunned & amazed that a last century oil viscosity ( 20w-50 ) worked well in a Porsche engine that was designed deep in the same century , who would of guessed ?

Now the double whammy came from the mid to late 1990's through to the early 2000's when a lot of the oil companies here in Australia were falling over them selves to see who could put less & less & less ZDDP in so called synthetic engine oils to show how Green they were & of course the lower viscosity engine oils for street usage gasoline cars came in for a real pounding & it got so bad there was a fad to replace ZDDP with Boron , this was to be the next big thing & boy OH boy did last century Porsche engines here in Australia suffer from excessive engine wear , we had }

A ) In the air cooled 911's , massive out of control valve guide wear& massive cam lobe wear & rocker to rocker shaft wear , excessive cam chain sprocket wear & even accelerated Thrust bearing wear & intermediate shaft ( alloy ) gear wear & unusual piston to cylinder wear

B) In the 944 & 944 turbo ( single cam engine ) accelerated cam lobe & lifter face wear( high loaded flat tappet design) , crank thrust bearing wear & lot of piston to cylinder wear , excessive valve guide wear

C ) In the 944S2 & 968 ( twin cam 16V ) accelerated cam chain sprocket wear & timing chain ( between cams) , just like you see on the 996 engines , and excessive wear to the cam lobes & lifter faces ( high loaded flat tappet design )
Excessive Cam Lobe Wear & lifter face wear

D ) 928S4 / GT / GTS Excessive cam chain sprocket wear & timing chain ( between cams ) & like on the 944S2 / 968 this was exasperated by using too low oil viscosity at idle by not allowing enough oil pressure to push the timing chain ( between cams ) tensioner/s to operate at the correct tension & at normal hot operational oil temp ( say 95 deg cel ) at idle with low oil pressure the timing chains would " RATTLE " , we called it the rattle of death because this was destroying the main & teeth of the sprockets with a oil that was not only low in viscosity but ver very very low in "Oil Film Strength "so it was basically metal to metal
Excessive thrust bearing wear
Excessive Cam Lobe & lifter face wear

Now the same last century Porsche engines described as above , but with a 20w-50 ( high oil film strength oil ) and we see none of that wear at all , but then again Porsche did tell us in the owners manual that came with Porsche cars in the 1970's , 1980's , 1990's & it stated on the oil viscosity page & in the centre of the chart there is the "Look at Me " shaded multi grade oil section & it states from minus 10 deg cel ( 14 deg Fah ) to unlimited high ambient temps } 15w-50 or 20w-50 oil viscosity

It got that funny here in Australia in the early 2000's that we even had a VERY famous oil company that thought " Gee wouldt it be a good idea" to drop the levels of ZDDP they had in their popular 15w-50 so called fully synthetic engine oil so it would meet the very strict new cars ACEA emissions protocols ( for the early 2000's ) , so they did & whammy , within two years we started to get phone calls from a couple of friends & colleague's/ indy Porsche specialists of ours who were using this brand of oil & they told me they were have all sorts of issues with massive valve guide wear in 911 engines they had assembled and some had only travel less than 20,000 Miles & the valve guides were chopped out & they were beside themselves with worry & asking me / us are we seeing the same & I answered no because we were using a different brand of oil that I had stuck with from when I was working at a Porsche dealership years before & that was a Valvoline 20w-50 and we had seen no change in the wear characteristics ( meaning no excessive wear )of any last century Porsche engines & these other independent Porsche specialists couldn't believe it , until the penny dropped , it took a few months of investigation and then they realised what had happened , and by the way the same oil company reinstated the higher levels of ZDDP , but it was too late for these guys and hundreds if not thousands of people around Australia , we escaped that carnage only because I stuck with decent quality 20w-50 engine oil

When I was at this large Porsche dealership in Sydney in the mid to late 1970's through to 1994 as a Porsche technical we saw a lot , and one of the things that stood out was an episode of multiple 3.0L 911 turbocharger failures the 1975/ 1976/1977/ and some 1978/79 3.3 Turbocharger failures in the late 1970's & the same for the 1979 & 1980 931 ( 924 turbo ) turbo charger failures , these were mainly the typical huge amounts of engine smoke out the exhaust etc
What happened next was interesting , we were using at the time a well known brand X engine oil at this Porsche dealership & it was a 20w-50 , but it was a very typical early mid 1970's engine oil ( as we now know ) and Porsche Cars Australia along with Bob Atkin a very skilled NZ engineer who partly owned our Porsche dealership heard of a engine oil that had become available in Australia at that time & this oil was simply called Valvoline Turbo V ( this has been superseded many times since), well blow me down , once we switched to it the turbo issues we were having just cleared up , the turbo's be it 911 or 931 were lasting longer & longer , it was quite amazing to us at that time , and all it was was Valvoline had made an engine oil that was rated at a higher temp so it could withstand the temps inside the turbo much better & it worked & forget about the Synthetic side of things , that word didn't even exist unless you were talking about a polyester shirt you might wear

Then came the era of the 951 (944 Turbo ) 1986 - 1990/91 , these would haver to be the Longest Living Turbo charger ever fitted to a Gas / petrol powered car ,let alone a sports / performance car
We have never to this day replaced a stuffed 951 turbo where the car has had regular oil changes with a decent 20w-50 , 200,000Kms , 300,000Kms , just amazing and not a drop of so called "Full" synthetic had been in any of them

Now I must mention , I keep on about oil film strength , in a last century Porsche engine its is VITAL for anywhere in the engine where there is NO oil pressure , meaning things like Valve Guides , Rocker Arms to Cam lobes , Cam Lobes , Cam Chain to Cam Chain Sprockets , Pistons to cylinders , Crank Thrust Bearings, Piston small end bearings & Gudgeon pin to piston , 911 intermediate gear ( alloy ), all these items rely on Oil Film Strength ONLY , there is NO Oil Pressure at these AT ALL, hence why high loaded flat tappet design engines ( like the twin cam 944/928) have completely disappeared in this century & the return in this century of OHC engines with roller rockers , be it Volvo , BMW , Merc , Porsche etc etc etc , because roller rockers do not require high oil film strength oils

A low viscosity this century engine oil , say a 5w-40 ( example ) and lets say this oil has the same ZDDP AW packages as a 20w-50 last century oil ( which its not allowed to ) but lets just say it does & you test the two oils for oil film strength , the 20w-50 is miles in front in keeping metal to metal parts away from each other

Now lets bring back the ZDDP AW packages to where it normally is on a Gas / Petrol so called fully synthetic & the 20w-50 is even further in front in oil film strength , particularly when one realises that some very trick 20w-50 oils have Molybdenum Dithiocarbamates( MoDTC )which with a high wiping load forms a MOS2 layer , so you can have what appears at first sight lower levels of ZDDP as compared to Racing oils that are low on detergents but high on ZDDP , but yet the moly works with the ZDDP to enhance it , its very clever but its the 20w-50 & ZDDP and the Moly content and how its done is just the icing on the cake

So ZDDP and what makes up ZDDP is not the total answer in last century high loaded flat tappet designed Porsche engines , but it is certainly a big part of the answer

The only thing I would do if we were using the Mobil V Twin ( which we do not ) , would be to change it more often , but the 20w-50 engine oils today are so good they leave what we had in the late 1970's in the dust , so do not be worried , they are all good & some are sensational

What I mentioned above is only the tip of the iceberg of 40+ years working on Porsche cars in Australia in regards to what we have seen some engine oils do in relation to last century Porsche engines in our climate

PS } Elephant in the room time , hands up anyone who has wondered on the subject of Fully Synthetic Engine oils , WHY do this century Fully Synthetic engine oils have to have any last century DINO additive from WW2 ( YES WW2 ) a AW package called ZDDP , you would of thought that all the millions spent $$$ hydro- cracking crude oil or Ester or PAO to make so called synthetic , that the stuff could stand on its own two feet to keep something as BASIC as keeping metal parts easy from each other , but no it can not so they still to this day add ZDDP , I find that the funniest Elephant in the room ever

Regards
Bruce Buchanan
Buchanan Automotive , 40 + years working on Porsche engines and still going
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coonabarabran

I am just changing out my 944S2 engine in Melbourne, by a well known old race driver's company as the engine after several years of track driving became what I can only describe as "rattlely". Sometimes when started it was more pronounced than others. When warmed up it rattles less. I still had power, but it was enough of a concern that I bought a donor long block out of Japan and had that completely rebuilt and it's being installed this week.

I'm going to get them not to put synthetic in it this time as they are big fans of 5W-40 or 5W-50 oils.

Funnily enough, my 951 engine is becoming "rattlely", rebuilt a couple years ago but I was driving the S2 to complete a year of class competition in PCV so didn't drive it much, if at all. When I did drive it, I had tons of power (compared to S2), but poor aero so the car is in Sydney for a spell of upgrades.

The turbo engine is a 3.0L block with the original 8V head on it. The original engine I still have, it was venting white smoke and is in the pulled out condition sitting in my warehouse in the corner of shame.

Is it possible, the rattlely condition these engines are getting to, is from the oil? Or the oil might be contributing to? Could also be my poor driving of course, I'm no genius there.

I'm guessing I should get all the synthetic oil out of the turbo engine immediately though.

Tiger03447

Nice post Bruce. Now I know which way to travel on this question. A lot of the racers around here (roundy-round guys) used to use Rotella diesel oil in their cars, now since they dropped the ZDDP in their oil, not so much..Most are now running Royal Purple and a ZPPD additive..Dow Corning back in the '70's used to sell an Moly additive which use to be good (at least I thought it was a good idea) but that was when I used Castrol, and there was no such thing a synthetic....and it wasn't in a Porsche.just an E-type Jaguar.

Dansvan

What about synthetic 20w-50 va Dino 20w-50?

Tiger03447

Lucas oil products makes a ZDDP additive FWIW. Should be pretty good stuff, since Lucas makes it.2 cents worth. I'll be using that in my engine .....someday. When it becomes a car again instead of a bunch of completed sub assemblies lying around the garage.