911 Engine oil preference

[tazzieman]

Has anyone here ever worn out an AC engine using the "wrong" oil?

I'll bet that guy in the USA with the one owner 1980 SC with >600,000km untouched bottom end engine (1000L oil over the years) has used factory recommended oil weight 

I am a believer in not overrevving a cold engine, that's just common sense.

[StevepGT3]

Don't think I'm taking this change of thinking easy as I've a 35 year habit of using 20w-50 in cars that I'm now questioning! Going to 15w-40 on my last change was big step and 5w-40 on the next will be another step to better exploiting modern technology.

 

Peter,

         I surely hope for your sake that you are correct, as not being so could turn out to be an expensive mistake down the road.There is plenty of evidence of cars using the factory recommended oil viscosity and original zinc level achieving many hundreds of thousands of miles/ km if treated correctly.These air cooled cars got their reputation of reliability and being bulletproof long before thin oils and emission friendly low zinc oils became fashionable.  I seriously question trying to fix something that is not broken, with products that are not proven, to achieve what ? Newer is not always better.

[clutch-monkey]

 

Peter,

         I surely hope for your sake that you are correct, as not being so could turn out to be an expensive mistake down the road.There is plenty of evidence of cars using the factory recommended oil viscosity and original zinc level achieving many hundreds of thousands of miles/ km if treated correctly.These air cooled cars got their reputation of reliability and being bulletproof long before thin oils and emission friendly low zinc oils became fashionable.  I seriously question trying to fix something that is not broken, with products that are not proven, to achieve what ? Newer is not always better.

 

true but as per taz's post:

 

Has anyone here ever worn out an AC engine using the "wrong" oil?

 

i've used essentially every product/weight mentioned in this thread and others, over ten years across two air cooled engines (one track, one street) and others. and never noticed a difference.

both have been dyno'd years apart with no loss of hp.

maybe when the engine gets rebuilt.. in five years plus, at this rate, i've never had to rebuild an engine at all.. i'll take a closer look.

 

it actually seems more important to get the gearbox oil right, than the engine oil exactly right..

[Peter M]

Steve,

I'm not advocating anything radical here at all.

15w-40 or 5w-40 aren't thin oils and any reasonable quality brand will meet Porsche's recommended HTHS viscosity.

(In fact some modern Xw-30 oils now meet this requirement but I'm not advocating these as the SH and later API service categories have limits on the phosphorous contents and thereby zinc which the Xw-40 and Xw-50 viscosities are not subject to. To clarify, I'm definitely NOT advocating low zinc or low/mid SAPS blends of any viscosity for our old 911's)

I'm the first to agree that 20w-50 has served us well but suggest oil technology has come along in leaps and bounds. Going from straight grades in the sixties to multigrades was a radical improvement. What I'm advocation is a relatively small change that will improve cold engine longevity and driveability and still give the hot protection we need.

 

I'm also the "victim" of worn cam lobes and lifters in other vehicles so I well aware of what's at stake. (Although the root causes of these failures are most likely poor metalurgy and geometry rather than the 20w-50 oils I was using at the time.) 

One of the surprises I've had recently is discovering that the majority of new cars across the world use 5w-30 and the use of 0w-20 is rapidly increasing. Definitely not advocating those viscosities for my 911's but just shows the rate of change and the technology at work.

I'd appreciate if you would read my previous recent posts and highlight any factual flaws in my proposition. However I'm  confident there isn't any as this is such a well worn path and frankly, has occurred while we've all been asleep at the wheel.

 

Regards

Peter

[Peter M]

 

it actually seems more important to get the gearbox oil right, than the engine oil exactly right..

Clutch, that's my increasing view too!

[tazzieman]

 

Clutch, that's my increasing view too!

Swepco or Kendall or Bobsuncle? 

[StevepGT3]

Steve,

I'm not advocating anything radical here at all.

15w-40 or 5w-40 aren't thin oils and any reasonable quality brand will meet Porsche's recommended HTHS viscosity.

(In fact some modern Xw-30 oils now meet this requirement but I'm not advocating these as the recent API service categories like SM and SN have limits on the phosphorous contents and thereby zinc which the Xw-40 and Xw-50 viscosities are not subject to. To clarify, I'm definitely NOT advocating low zinc or low/mid SAPS blends of any viscosity for our old 911's)

I'm the first to agree that 20w-50 has served us well but suggest oil technology has come along in leaps and bounds. Going from straight grades in the sixties to multigrades was a radical improvement. What I'm advocation is a relatively small change that will improve cold engine longevity and driveability and still give the hot protection we need.

 

I'm also the "victim" of worn cam lobes and lifters in other vehicles so I well aware of what's at stake. (Although the root causes of these failures are most likely poor metalurgy and geometry rather than the 20w-50 oils I was using at the time.) 

One of the surprises I've had recently is discovering that the majority of new cars across the world use 5w-30 and the use of 0w-20 is rapidly increasing. Definitely not advocating those viscosities for my 911's but just shows the rate of change and the technology at work.

I'd appreciate if you would read my previous recent posts and highlight any factual flaws in my proposition. However I'm  confident there isn't any as this is such a well worn path and frankly, has occurred while we've all been asleep at the wheel.

 

Regards

Peter

Mate, my head would explode if I tried to do that, and I am sure that your research is fine. But if there are engine builders out there with many years of hands on experience who don`t agree, I for one will keep my head in the sand and go with what`s known to work rather than opt for something that theoretically should work better, but has yet to be proven in an air cooled application. 

[Peter M]

LOL, you 20w-50 guys can stick with what you're comfortable with, there is no problem with that!

 

To get it into prospective we are talking the difference between "good" and "better" rather than "good" and "bad"
 
Even Steve Weiner was advocating a 15w-40 so we are not that far apart.
 
Cheers
Peter

[tazzieman]

And Porsche are marketing 10W-60 nowadays!

 

[Peter M]

Has anyone here ever worn out an AC engine using the "wrong" oil?

I'll bet that guy in the USA with the one owner 1980 SC with >600,000km untouched bottom end engine (1000L oil over the years) has used factory recommended oil weight 

I am a believer in not overrevving a cold engine, that's just common sense.

 

 

And Porsche are marketing 10W-60 nowadays!

 

Let me guess Taz, you're a "20w-50 Extra 10" guy!

I can't make head nor tail about the Porsche Classic oil recommendations.  It doesn't help that there doesn't seem to be any real data published either.  But the graphics on the tin is nice so I guess that's all that matters in the end.

 

[tazzieman]

 

Let me guess Taz, you're a "20w-50 Extra 10" guy!

I've admitted as much previously. I like to keep things simple across the range of old Porsches I own.

Kellogg's all the way , and Australian made. If there was a Tasmanian oil I'd use that.

 

Hmm this is promising , just whack some zinc capsules in it, healthy summer here we come

 

[StevepGT3]

LOL, you 20w-50 guys can stick with what you're comfortable with, there is no problem with that!

 

To get it into prospective we are talking the difference between "good" and "better" rather than "good" and "bad"

 

Even Steve Weiner was advocating a 15w-40 so we are not that far apart.

 

Cheers

Peter

I`ve actually been running 15/50 4 t racing mobil 1 for about 4 years now as it is within spec was the only oil I could source locally with a decent amount of zinc at the time. 

On a reverse note and to put this into perspective how do you think a modern car designed to run on 0/20- 0/30 or 5/40 would go on 20/50. I don`t think there would be so many different grades and types of oil out there if different engine requirements didn`t exist.

[clutch-monkey]

Mate, my head would explode if I tried to do that, and I am sure that your research is fine. But if there are engine builders out there with many years of hands on experience who don`t agree, I for one will keep my head in the sand and go with what`s known to work rather than opt for something that theoretically should work better, but has yet to be proven in an air cooled application. 

 

i started on 15w40, 10w40, 5w40 etc on my engine builders advice.. his engine has been tracked even longer than mine! never used 20w anything. i don't think i know anyone who does still use 20w40 actually

that's not to say it's wrong, but just seems most people have changed from it. 

again though, this is all the track/street car crowd so oil gets dumped so often there is no time for any long term benefits to set in.

[Peter M]

Engine Oil for Air Cooled 911’s – Select in 3 Easy Steps

The other day I was asked by someone who only has a passing interest in engine oil (can you imagine that!) on how they should select and offer the following suggestion:

1) Drive to your favourite auto parts store.
There is no need to special order oil over the internet and pay high shipping for some oil that has internet folk law, just go to your local store or service station.

2) Choose your viscosity grade preference.
For our purposes, something between 0W-40 and 20W-50 will be fine.
Don’t waste sleep on this as it doesn’t materially matter as we will neither live long enough nor have enough objective data to be definitive in our choice.

3) Porsche A40 Approved or a Suitable API/ACEA Service Classification?
Your Driver Manual probably references API service classification like SH, SJ, SL or similar which was all that was available at the time and have been long superseded by much better oils.

If money is no object, just buy 10 litres of Porsche A40 approved oil. You pay a premium for this but if anyone knows best, it has to be the manufacturer. However the likely number of oils on the shop shelves that have this approval will be small, will take some reading of labels to identify these few and you will pay a substantial premium for this comfort.

However if you can’t see the value in using a Porsche approved oil, I suggest choosing an oil that meets ACEA specification A3/B4. Why? The ACEA A3/B4 approval will guarantee a High Temperature High Shear (HTHS) of greater than 3.5 mPa.s just like Porsche themselves specify and the relatively high ash (SAPS) limit of 1.6% does not adversely limit the use of anti-wear additives. There are other good reasons too but that's for another time.

Using the ACEA rather than the API classifications also makes it simpler in identifying suitable oils because of this direct correlation between what Porsche specify and what the A3/B4 specification delivers.

Applying the above gives plenty of choice. For example at Supercheap Auto you could comfortably choose any of the following, depending on your brand name preference and budget:

Castrol Edge 10w-60 for $79/jug
Chief Cheyenne Engine Oil - 20W-50 for $25/jug
Penrite HPR10 10W-50 for $49/jug
Penrite HPR15 Diesel 15 15W-50 for $75 for 10 litres
Shell Helix HX7 10W-40 for $34/jug
Shell Helix Ultra 5w-40 for $65/jug - Meets the Porsche A40 specification as well.
Valvoline Synpower 10w-50 for $65/jug

etc etc

Keep looking and you’ll find there is another dozen or so other suitable oils on the shelves.

 

Now how easy was that?

Edited 8August, 2015 by Peter M

[TINGY]

You need to get out more Pete you have way too much time on your hands.

[Peter M]

Tingy,

 

I needed to cheer myself up today and just couldn't help myself!

 

I've done pretty good you must admit, first long oil post in 4 months so am improving....

[Coastr]

I notice several chains seem to be having 25% off sales this weekend, might go and buy the next change worth.

Key question...of those oils, which one do you prefer? My car currently has penrite in it, but that's not usually a brand I go for.

[tazzieman]

Penrite is Aussie tough , go straya 

[Peter M]

I notice several chains seem to be having 25% off sales this weekend, might go and buy the next change worth.

Key question...of those oils, which one do you prefer? My car currently has penrite in it, but that's not usually a brand I go for.

 

It's pretty difficult to have one preferred oil when discounting makes it tempting to take whatever meets the  spec and save a few bucks.   Last year Repco were selling a name brand Porsche A40 approved oil at a 55% discount or $29/jug and I regret I didn't buy more at the time.  That's cheaper than the oil I normally put in my kid's junkers! 

 

I've tried hard to base my previous post on cold objective fact and am afraid that if I nominate a particular oil I'll expose my unfounded emotional bias with regard to brands but here goes: If I was doing an oil change this weekend I would probably buy Shell Helix HX7 10w-40 on sale for $27/5 litres from Supercheap Auto even though I know Autobarn have a same viscosity grade Castrol Magnatec even cheaper this weekend at 20 bucks a jug! 

(I do freely admit to favouring Castrol for transmission fluid though!)

 

BTW: For those with an ZDDP anxiety, the Shell Helix contains 1250ppm of zinc so should give you comfort to give it a try.

Then again why penny pinch when I can get Shell Helix Ultra 5w-40 for $65/jug anytime....

 

Who'd a thunk, an oil thread with an unsubstantiated emotional based response!

[tazzieman]

 an oil tread 

 

You've drunk so much Caltex you're now even sounding like Sol !

 

[Peter M]

Like Sol I know what I mean Taz!

[AC78]

Anybody bought any of the Classic oil in the cool can? I went to local P dealer about 6 months ago and spares guy told me all cans to Oz were damaged in shipping, said id come back when new batch arrives.

[Uncle]

Used Penrite HPR30 for years. 

 

Be very careful with any diesel oils. They have quite a bit of detergent in them. Not so good for older motors.

[Peter M]

Yes Uncle, I certainly don't advocate diesel only classified oils for our purposes.

I've assumed with the above recommendations that the engine is in good condition, has been regular serviced with regular oils and street driven. Anyone with a 356 that has run on non detergent SAE30 all its life should do some research of their own.
 

 

 

 

 

Just as an aside for the masses that find oil labelling fascinating - stop laughing Tingy! - is that most engine oils we use are dual classified for use in both petrol engines and light duty diesels.

 

Penrite's HPR15 Diesel 15 15W-50 that I mention above, whilst described as a diesel oil on the front label has the following dual API and ACEA classifications and can be used for both fuel types:
•API CI-4 PLUS/SL - where left of the / is the Compression ignition API classification and on the right is the Spark ignition classification
•ACEA A3/B4 and E7 - where A3/B4 is the ACEA classification for high performance petrol and diesel passenger vehicle engines and the E7 indicates it also meets that specification for heavy duty diesel engines that don't run exhaust particulate filters.  

[Peter M]

Oil Consumption Update
 
Until September last year I was using Mobil Super X2 1000 20W-50 in my Carrera 3.2 as it is the default fill at one of the big independent workshops in Sydney and I know many other owners use it too.

http://www.mobil.com/AP-English-LCW/carengineoils_au_products_mobil-super-1000-x2-20w50.aspx#

After a bit of head scratching and my belief at the time that I really needed a high ZDDP oil I changed to a well regarded mix fleet oil Caltex Delo 400 15W-40.

http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB0QFjAA&url=http%3A%2F%2Fwww.caltex.com.au%2FFPL%2520PDS%2FDelo%2520400%2520Multigrade.pdf&ei=CSAfVZ-GCsK3mAXZ34G4Dg&usg=AFQjCNEpoPcNxzjYnsNk-B23QS0Ir9t5Kw

I expected the oil consumption to remain similar or even increase slightly given the lower viscosity grade but have found the opposite to be true. Over the last 3621km it is averaging just over 70ml/1000km which is less than half it was using previously and especially remarkable when Porsche's upper consumption limit for these engines is 1500ml/1000km.

 

For my next change due in September I'll just heed my own A3/B4 advice above.