987.2 / 2.9 oil level and white smoke corrolation?

[911hillclimber]

Oh so pleased to report no while smoke on cold start for months and months.
Just taken the Boxster for a calm run to actually fill it with Shell 95 octane fuel, a good round trip of 16 miles, and a simple 'in traffic' A road run.
Got home just on the level and 40 seconds later the oil dash gauge shows one empty segment below the arrow so two empty segments from over-full.

Could having a segment less oil ease the white smoke syndrome? The car had an interim oil change by the trusted Zuffenhaus in early Feb, so the re-fill might have been 'light', but the car was smoke free (by coincidence) when I cured the coolant leak up front, so about 6 months ago. (coolent level seems stable at 1/2 way Max to Min.

Tempted not to add oil to fill the empty segment and bring the level to the arrow.
any thoughts please?
Graham.

We'll soon be free!

 

[CLIFFWILKINS]

A notch of two down will be fine just keep an eye on it if the segment drops another maybe add a tad of the same oil already fitted.

 

[laura]

I always kept the 987S around the middle of the level gauge. []

 

[AndrewCS]

" Could having a segment less oil ease the white smoke syndrome ? "

From non Porsche experience ... yes, reduces crankcase oil foaming due to crank `splash` and hence the load on the breathing - return to intake system. Oil use is therefore reduced

Am I correct in saying that the Flat 6 uses an oil scavenge system whereby there is less possibility of foaming due to crank `splash` ?

(The GT4 manual recommends one segment down from MAX for track use)

 

[Motorhead]

That’s always a possibility Graham, and I can’t believe that running with a marginally lower oil level will do any harm, especially if you’re not ‘ragging’ the engine as you would on track perhaps.

Lower rather than higher always seems to be the common mantra regarding oil level on these engines, so I’d be inclined to give it a go for a while. If it works long-term in fending off the dreaded start-up white smoke then you may have cracked it … at last!

Jeff

 

[911hillclimber]

Thank you for the replies.
on my ex hillclimb 911 with a 3.2 flat six, the oil, hot and running is mid way between max and min.
A very Porsche wise man, Bob Watson, instructed me in that many years ago.
I once over filled the system and the while smoke was literally blinding via the rear view mirror...
Interesting Laura's daily Boxster has oil the same way, but she's a '911 Girl' really!
Ive emailed Zuffenhaus for the grade of oil they used for the last oil change.
A litre in the boot will be a good insurance.

 

[911hillclimber]

As expected, had an immediate reply from Zuffenhaus.
They have detailed the grade and type of oil used which I happen to have in the car's front box, and say to leave it as it is (the oil level) and check regularly, so that is the game plan.
The car has never used oil for the 4 years I've owned it. I think the dash oil gauge is an indicator rather than a precise measurement device.

Bring back dip sticks!!

 

[AndrewT]

Bring back dip sticks!!

They never went away, I see them every day on the roads around here ??.

 

[1975turbo]

Very interested to come across this post from a modern Boxster owner. I thought this problem was confined to early 911 engines. My '75 3.0 turbo exhibits this trait. Full to the max marker on the dipstick results in the dreaded "white smoke syndrome" (and manic signalling from all around that you have blown your engine!).
This "problem" has been around for a very long time and I have yet to hear a convincing explanation as to why it happens (and why it didn't happen when they were new). I expect there is a fully reasoned explanation somewhere and I'd be very pleased to find out where, if someone can point me in the right direction. I have always been advised to not trust the dash gauge and only fill the tank to the middle point, when the oil is hot and the engine been ticking over for sufficient time for the level to stabilise.

 

[Motorhead]

I think the dash oil gauge is an indicator rather than a precise measurement device.

Bring back dip sticks!!

+1 on that Graham! But at least we’re still able to ‘eyeball’ the coolant level and check tyre pressures as a backup to electronic monitoring.

I suppose we’ve got accustomed to having remote monitoring of oil pressure and coolant temperature - and have developed a degree of confidence in the technology - so there’s no reason to believe that oil level monitoring shouldn’t be equally robust.

Jeff

 

[CLIFFWILKINS]

Just my observations on various Porsches I have owned.
As said later cars have the dashboard electronic segments gauges, most I have owned either stick at the top or one segment down and stay there until its next oil change.
My GT3 would drop 2 segment bars soon after an oil change I would top it up each time to the top segment only to drop 2 bars again every time.
But if I left it at 2 bars down it never dropped anymore.
So as been said maybe not precise rather an indication.
Much prefer a dipstick not hard to dip it occasionally.

 

[911hillclimber]

I bought my 1973T in 1988, it had a 2.2 engine.
Knowing nothing about the 911 dry sump, or even what is a dry sump engine, I filled the tank to the max, cold and engine off....it was on level ground though.
after draining it after the attempted start I read a book, and started on my 911 adventure and it's wacky nature.
Still learning and on its 3rd engine, the car has survived so far.
Bob Watson told me to never go over 1/2 way on the stick marks, and lm very obedient having been married to The Boss for 43 years, so never knowingly broke the rule except once and lots of white smoke. Oil gets up through engine breather pipe and back to the inlet via the knock of the dry sump tank.
white smoke only needs a drop or two to be blinding..

 

[Motorhead]

Graham,

I’m sure you’re aware that although the F-6 configuration is common, the air-cooled engines are truly dry-sumped whereas the water-cooled engines aren’t, having an integral sump, although the heads have separate scavenge pumps. On that basis I’m not sure that Bob’s half-full recommendation applies equally to the water-cooled engines, although your current experience seems to indicate a benefit in dropping the oil level slightly.

Jeff

 

[911hillclimber]

Yes, up to speed on all that, my air cooled experience might help a poster above with his early car.
I have run this car where previous services have set the oil after numerous oil changes, I have never put oil in this car.
Next run out and oil check will be interesting to see if the level shows 'full'. I could be just on the flip point of 'Full' and one segment down.

Will report back. For now wil leave alone and check progress (or otherwise).

My daughter has an AUDI TT just 3 years old and the wife said yesterday she really liked the car.
Oh dear.

 

[Motorhead]

I suppose that the sensor’s calibration is the key factor in all this Graham, i.e. when does 2+ bars become 3 bars, etc.

Jeff

 

[911hillclimber]

When I used to design weighing machines, we called that the flip point when the digital display would flip from 21.3 to 21.4 for example.
For Weights and Measures this flip point and it's repeatability was critical.
I doubt Porsche would be too fussed about dead accuracy and repeatability!

 

[MoC2S]

Graham,
I’m sure you’re aware that although the F-6 configuration is common, the air-cooled engines are truly dry-sumped whereas the water-cooled engines aren’t, having an integral sump, although the heads have separate scavenge pumps. On that basis I’m not sure that Bob’s half-full recommendation applies equally to the water-cooled engines, although your current experience seems to indicate a benefit in dropping the oil level slightly.
Jeff

I thought, but can't check right now, that all GT3s, 997 Gen 2 and later 911s had full dry sump, but as I said, that's off the top of my head ..

Re flip points, the creators of the algorithms would ultimately decide when to increment / decrement, normal logic says increment > 1/2 way, decrement < 1/2 way, but somewhere they need to be measuring the next decimal place ..

I remember going out in my Europa Twin Cam with a toolbox, a plastic bag with 2 types of transistors, A2 sized (at least) books of logic equations, circuit diagrams and an oscilloscope .. what fun !

I still miss it .. [8|][]

cheers, Maurice

 

[Motorhead]

Maurice,

Re full dry-sump, you’re partially correct. I believe that all GT3s (and maybe GT2s?) are dry-sumped - Mezger and all later engines in the series, even up to the present day - but all the basic cars from the 986/996-series onwards have what’s called an integrated dry-sump system … which just translates to a sump in my book. []

Jeff