Oil Pressure
05-16-2011, 02:37 PM
#32
Race Director
I understand your concerns quadcammer, but i will just have to be wrong along with these people.
We all choose different oils for different circumstances i guess, but any on the type approval list should be ok...
We all choose different oils for different circumstances i guess, but any on the type approval list should be ok...
Amazing also how one oil is suitable for all engines from 1984 to present despite signifcant differences in those engines.
Now, Steve Weiner, a very well known and well respected porsche mechanic tends to think 15w-50 or similar is a much better choice.
Hi Marv:
There are 2 main causes for noisy lifters (aside from oil pressure issues:
1) Foreign matter inside lifter
2) Failed lifter seals from heat & age (most common)
The 15w-50 protects these engines better than the thinner stuff in really hot weather and on the track. Remember now, the oil temp guage only shows indicated temperature at that point in the engine. There are much hotter places that the oil must contend with.
(nice avatar, BTW)
There are 2 main causes for noisy lifters (aside from oil pressure issues:
1) Foreign matter inside lifter
2) Failed lifter seals from heat & age (most common)
The 15w-50 protects these engines better than the thinner stuff in really hot weather and on the track. Remember now, the oil temp guage only shows indicated temperature at that point in the engine. There are much hotter places that the oil must contend with.
(nice avatar, BTW)
The oil temp sensor on 3.6's is at the front of the engine by the pressure sender. Its difficult to install senders in different spots along the main oil galleys and in the cam towers on these, but close inspection reveals the kinds of carbon deposit formation from certain temperatures (based on oil). I've measured 20 deg temp differentials on older 911 motors (2.7-3.0-3.2-3.3) by installing the oil temp sender in alternative places.
The 0-40 was specifically made to work with the hydraulically-controlled camshafts found in the 996's.
15w-50 was too thick at low temps to permit the cam timing to change and these engines did not pass smog (OBD-II compliance) until the 10w-40 & 0w-40 oils were introduced.
Porsche recommends these products as a matter of expediancy so they do not need to stock several oil viscosities.
15w-50 was too thick at low temps to permit the cam timing to change and these engines did not pass smog (OBD-II compliance) until the 10w-40 & 0w-40 oils were introduced.
Porsche recommends these products as a matter of expediancy so they do not need to stock several oil viscosities.
05-16-2011, 02:53 PM
#33
I really don't want to get into a big debate over oil, considering this thread wasn't about a specific oil and more about how it works at low temps and how manufactureres are moving towards the function of oil at start up. But if you take the time to view the type approval list you will see it has more than one oil on it, in fact it has more that 60 oils, but it was the theme of all of the oils that started the debate and in essence are all the manufacturers wrong? That was the debate.
I imagine it doesn't have some that would be elegable, as some have not put themselves forward for type approval for unknown reasons, but for many users it is a useful guide. I will continue to experiment within the manufacturers guide lines and from the list, just the same as others will outside of the specs.
I hope your car gives you many years of trouble free enjoyment whatever the oil choice
I imagine it doesn't have some that would be elegable, as some have not put themselves forward for type approval for unknown reasons, but for many users it is a useful guide. I will continue to experiment within the manufacturers guide lines and from the list, just the same as others will outside of the specs.
I hope your car gives you many years of trouble free enjoyment whatever the oil choice
Last edited by Unkle; 05-16-2011 at 03:43 PM.
05-16-2011, 05:50 PM
#34
Race Director
the manufacturers approve oils for their current needs, not the needs of their vehicles that are 20 years old.
if you want to use thin oils and risk your engine, the only one to blame is yourself.
if you want to use thin oils and risk your engine, the only one to blame is yourself.
12-08-2011, 04:46 PM
#36
10/40 for me......
Why?........**** knows ,just sort off in the middle I guess...I try not to think about it to much as when I try to understand it all it just gets even more confusing....or is it just me!!
I'm off to get a beer from the fridge to help me think!!.......
Why?........**** knows ,just sort off in the middle I guess...I try not to think about it to much as when I try to understand it all it just gets even more confusing....or is it just me!!
I'm off to get a beer from the fridge to help me think!!.......
12-08-2011, 05:08 PM
#37
At the end of the day it's not about the weight oil as it about the additives, and a 0W-40 has different adds than 20W-50. If you are really conserned about it you need to know what is required, what the manufacturer's specifications are and what oil by what company meets those needs. It's all about the additives, and you can have very similar, in some cases the exact same weight, oils with completely differenct compositions.
12-09-2011, 12:31 PM
#39
Nordschleife Master
http://papers.sae.org/922342
"Engine Oil Viscosity and Bearing Wear: Field Test Results
Date Published: 1992-10-01
Paper Number: 922342
DOI: 10.4271/922342
Author(s):
Richard A. Demmin - Exxon Research & Engrg. Co.
Fred Girshick - Exxon Research & Engrg. Co.
Alan M. Schilowitz - Exxon Research & Engrg. Co.
Abstract
Two programs were conducted to study the relationships between engine oil rheology and crankshaft bearing wear. A Chassis Dynamometer test of four oils in four cars was used to explore and define the key variables affecting bearing wear. These results were used to design a Field Test of nine oils in 45 taxicabs in New York City. The test oils (SAE OW-20 to 20W-20) were formulated to measure the effects of viscosity, viscosity index improver, and detergent inhibitor package. Bearing wear tended to be either low and unremarkable or very high, particularly in the thrust bearings. Oil performance was best expressed as the frequency of excessive wear, rather than by quantitative wear measurement. There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. Non-Newtonian oils appeared to provide slightly more protection than Newtonian oils of the same HTHS viscosity, and a higher quality adpack also appeared to provide benefits. However, these factors were secondary to the viscosity of the oil. HTHS viscosity was a better predictor of bearing wear performance than oil film thickness."
"There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. "
Anyone who uses thin oil when its not needed is endangering their motor .
If you live in a place where it gets down to -35C/-31F then you might need to run a ZeroW weight oil .
"Engine Oil Viscosity and Bearing Wear: Field Test Results
Date Published: 1992-10-01
Paper Number: 922342
DOI: 10.4271/922342
Author(s):
Richard A. Demmin - Exxon Research & Engrg. Co.
Fred Girshick - Exxon Research & Engrg. Co.
Alan M. Schilowitz - Exxon Research & Engrg. Co.
Abstract
Two programs were conducted to study the relationships between engine oil rheology and crankshaft bearing wear. A Chassis Dynamometer test of four oils in four cars was used to explore and define the key variables affecting bearing wear. These results were used to design a Field Test of nine oils in 45 taxicabs in New York City. The test oils (SAE OW-20 to 20W-20) were formulated to measure the effects of viscosity, viscosity index improver, and detergent inhibitor package. Bearing wear tended to be either low and unremarkable or very high, particularly in the thrust bearings. Oil performance was best expressed as the frequency of excessive wear, rather than by quantitative wear measurement. There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. Non-Newtonian oils appeared to provide slightly more protection than Newtonian oils of the same HTHS viscosity, and a higher quality adpack also appeared to provide benefits. However, these factors were secondary to the viscosity of the oil. HTHS viscosity was a better predictor of bearing wear performance than oil film thickness."
"There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. "
Anyone who uses thin oil when its not needed is endangering their motor .
If you live in a place where it gets down to -35C/-31F then you might need to run a ZeroW weight oil .
12-09-2011, 05:27 PM
#41
http://papers.sae.org/922342
"Engine Oil Viscosity and Bearing Wear: Field Test Results
Date Published: 1992-10-01
Paper Number: 922342
DOI: 10.4271/922342
Author(s):
Richard A. Demmin - Exxon Research & Engrg. Co.
Fred Girshick - Exxon Research & Engrg. Co.
Alan M. Schilowitz - Exxon Research & Engrg. Co.
Abstract
Two programs were conducted to study the relationships between engine oil rheology and crankshaft bearing wear. A Chassis Dynamometer test of four oils in four cars was used to explore and define the key variables affecting bearing wear. These results were used to design a Field Test of nine oils in 45 taxicabs in New York City. The test oils (SAE OW-20 to 20W-20) were formulated to measure the effects of viscosity, viscosity index improver, and detergent inhibitor package. Bearing wear tended to be either low and unremarkable or very high, particularly in the thrust bearings. Oil performance was best expressed as the frequency of excessive wear, rather than by quantitative wear measurement. There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. Non-Newtonian oils appeared to provide slightly more protection than Newtonian oils of the same HTHS viscosity, and a higher quality adpack also appeared to provide benefits. However, these factors were secondary to the viscosity of the oil. HTHS viscosity was a better predictor of bearing wear performance than oil film thickness."
"There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. "
Anyone who uses thin oil when its not needed is endangering their motor .
If you live in a place where it gets down to -35C/-31F then you might need to run a ZeroW weight oil .
"Engine Oil Viscosity and Bearing Wear: Field Test Results
Date Published: 1992-10-01
Paper Number: 922342
DOI: 10.4271/922342
Author(s):
Richard A. Demmin - Exxon Research & Engrg. Co.
Fred Girshick - Exxon Research & Engrg. Co.
Alan M. Schilowitz - Exxon Research & Engrg. Co.
Abstract
Two programs were conducted to study the relationships between engine oil rheology and crankshaft bearing wear. A Chassis Dynamometer test of four oils in four cars was used to explore and define the key variables affecting bearing wear. These results were used to design a Field Test of nine oils in 45 taxicabs in New York City. The test oils (SAE OW-20 to 20W-20) were formulated to measure the effects of viscosity, viscosity index improver, and detergent inhibitor package. Bearing wear tended to be either low and unremarkable or very high, particularly in the thrust bearings. Oil performance was best expressed as the frequency of excessive wear, rather than by quantitative wear measurement. There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. Non-Newtonian oils appeared to provide slightly more protection than Newtonian oils of the same HTHS viscosity, and a higher quality adpack also appeared to provide benefits. However, these factors were secondary to the viscosity of the oil. HTHS viscosity was a better predictor of bearing wear performance than oil film thickness."
"There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. "
Anyone who uses thin oil when its not needed is endangering their motor .
If you live in a place where it gets down to -35C/-31F then you might need to run a ZeroW weight oil .
anyway some threads are best left to die
12-10-2011, 02:48 PM
#42
Rennlist Member
i am useing 10w 40 high milage syn . seams to work great for me . the oil is running about 4.5 bar at start and 2.5 bar at hot . i did notice that if the oil filter is new it makes a little lower readings.
nick
nick
05-09-2012, 12:15 AM
#43
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I had 1.5 bar at idle and 5 bar at 5k rpm until I took my pistons and cylinders out to replace the through bolt o-rings at 160k miles. I noticed that the oil rings on the pistons were all gunked up with carbon, so, I took them all out and cleaned them. Now the oil pressure is .5 bar at idle when hot and 4.5 at 5krpm. I thought that was interesting--that high oil pressure might be a symptom of restricted internal flow due to carbon buildup.
dt 1991 964
dt 1991 964
05-09-2012, 10:04 AM
#45
Nordschleife Master
Prior to our now infamous road trip to Spa Francorchamps, I had an unscheduled oil change to make sure the car was fit for the trip. Up until that point I had been happily using Mobil Motorsport 15W-50. Mostly chosen because of the extra protection it gives on track. However, at the oil change only Mobil Motorsport 10W-60 was available. Apparently, Mobil have discontinued 15W-50 and replaced it with 10W-60. So, since Mobil knows best (tongue in cheek) the new 10W-60 was put in.
Only a few miles into the trip on the motorway, I got the feeling (seat of my pants) that the car was not pulling aswell as it used to. This continued throughout the trip. There just seemed to be a reduction in the urgency of the revs to rise when I pressed the throttle. Especially in 4th or 5th gear. Not so apparent when hammering the car in the early gears. Even on track at Spa on the fastest straight (Kemmel) the car felt a bit sluggish. I didn't get close to the top speeds I expected.
The other effect I noted on the journey home is that the oil temperature, when in traffic, got much higher than I'd ever seen it before. It got to nearly 10 o'clock at one point.
I didn't put any of the above down to the different oil that had been put in the car.
After I had returned from the trip I later came across the article below which has been written by an expert from the oil industry that advises Porsche Club GB:
http://www.opieoils.co.uk/pdfs/tech-...10w-60-oil.pdf
In summary, it says that 10W-60 is not suitable for most engines. Even if they are tracked hard. Including Porsches. It's too viscous when at its hot temperature, leads to higher temperatures in the engine and saps power!
This was like a eureka moment to me! So at the next opportunity I took out the 10W-60 and put some 5W-40 synthetic oil in (I'm not promoting the latter but I'd used it before and had been happy with it). The difference in the drive was immediate. The engine's urgency returned and it feels like it used to before the thick oil was put in. On the next trackday, the car felt back to its best again.
I'm no oil expert and even though this is only a 'seat of my pants' anecdote I thought it was worth mentioning in case anyone has recently switched to 10W-60 or is thinking of doing so.
p.s. Please read the article linked above because it's a lot more scientific than my anecdote.
