Oil Flow Diagram
08-14-2004, 07:05 AM
#1
Drifting
Thread Starter
Join Date: Jun 2003
Location: Taiwan
Posts: 2,101
Likes: 0
Received 0 Likes
on
0 Posts
Oil Flow Diagram
Hi Guys,
Has anyone analyse the oil flow diagram ?
It seems unlogical to me that the oil will
first flow into the cooler before the filter
& thereafter to the engine.
Has anyone analyse the oil flow diagram ?
It seems unlogical to me that the oil will
first flow into the cooler before the filter
& thereafter to the engine.
08-14-2004, 08:21 AM
#4
Drifting
Thread Starter
Join Date: Jun 2003
Location: Taiwan
Posts: 2,101
Likes: 0
Received 0 Likes
on
0 Posts
Sam, look at the schematics that Hosrom has posted.
There should be 2 oil feed lines. One from the pressure
relief valve straight to the filter while the other line from
the filter to the oil thermo before feeding the oil cooler.
When I dismantled the oil filter housing, this is what I
saw. If oil is being fed through the cooler first, why should
there be an oil thermo there. Besides, how would the oil
be circulated to the engine when cold with the oil thermo
shutting off the oil supply ?
There should be 2 oil feed lines. One from the pressure
relief valve straight to the filter while the other line from
the filter to the oil thermo before feeding the oil cooler.
When I dismantled the oil filter housing, this is what I
saw. If oil is being fed through the cooler first, why should
there be an oil thermo there. Besides, how would the oil
be circulated to the engine when cold with the oil thermo
shutting off the oil supply ?
08-14-2004, 02:23 PM
#5
Addict
Rennlist Member
Rennlist Member
That diagram does not show the oil thermostat, as it's considered part of the oil cooler. When it's closed, it simply bypasses the cooler. The thermostat does not function like the coolant thermostat in that it totally blocks flow when closed - instead, it is a thermal valve that switches the oil between 2 flow paths based on the oil temperature. The 2 paths either go through the cooler or skip the cooler.
Sam
Sam
08-14-2004, 09:09 PM
#6
Three Wheelin'
Not to hijack this, but it is related. The oil thermostat is rated for 105 degrees C. That seems a bit hot to me. I know the oil needs to be hot enought to boil the water out, but 105? Is there another one available?
08-15-2004, 02:54 AM
#7
Burning Brakes
Join Date: Dec 2002
Location: Airlie Beach, Australia
Posts: 870
Likes: 0
Received 0 Likes
on
0 Posts
Hi,
typically a car's oil cooler operates at a later stage of the engine's cooling "cycle". They are excellent at quickly removing heat from the sump's residual (base/core) base number plus the extra resulting from compession of the oil via the pump (this alone may add 10-20C). They are usually not open continuously unless the engine is working extremely hard but rather open in short cycles to maintain the engine's overall core temperature - via the oil
The anti-wear and other chemicals are active above about 45C-60C and the polymer viscosity "linkages" are progressively changing as the temperature builds giving all oils their 100C SAE viscosity and etc. ratings. It is best to keep engine oil above 80C and most of Porche's engine performance measurements are carried out with oil in the 80c-100C band.
Moisture is despatched very early on as the engine warms up due to the oil's contact with many very hot parts - the piston undercrown area or the turbocharger usually being the hottest
Oil usually operates at from about 80C to 120C and at up to 130C continuously on some engines such as the BMW M3 (some) when worked hard. Over 130C is stretching the oil's operating envelope near it's limit. This is especially so with mineral oils that are not ACEA A3/B3 rated and are not Heavy Duty Engine Oils (HDEOs) as used in mixed fleets - diesel oils!
Generally the more expensive fully synthetic oils - especially those that are ACEA rated A3/B3 - have extremely good high temperature operational characteristics with low volatility and strong High Temperature High Shear (HTHS) vis. @150C (Porsche's minimum is 3.5) performance. HDEOs are rated differently (at higher duraility levels) and will operate very well in our engines especially those that are turbocharged as they have excellent deposit and corrosion control additives. These will have a CI-4/SL rating on the label
It is always important to use the correct viscosity oil for your car and this linkage may be of some interest to you;
http://www.landsharkoz.com/techtips.htm
Check under "Lubricants for the 928"
Sam - your comments are excellent. There is also a differential relief valve to protect the oil cooler and a differential by-pass valve in the oil filter to prevent damage to the filtering media and the filter as a whole. The by-pass is especially important with all oils when cold and especially the more viscous types - one good reason to always use a MANN or MAHLE filter. Our engines operate at very high pressure compared to most others. Until the oil is up to about 60C use engine revs above about 3000 rpm sparingly!
Regards
typically a car's oil cooler operates at a later stage of the engine's cooling "cycle". They are excellent at quickly removing heat from the sump's residual (base/core) base number plus the extra resulting from compession of the oil via the pump (this alone may add 10-20C). They are usually not open continuously unless the engine is working extremely hard but rather open in short cycles to maintain the engine's overall core temperature - via the oil
The anti-wear and other chemicals are active above about 45C-60C and the polymer viscosity "linkages" are progressively changing as the temperature builds giving all oils their 100C SAE viscosity and etc. ratings. It is best to keep engine oil above 80C and most of Porche's engine performance measurements are carried out with oil in the 80c-100C band.
Moisture is despatched very early on as the engine warms up due to the oil's contact with many very hot parts - the piston undercrown area or the turbocharger usually being the hottest
Oil usually operates at from about 80C to 120C and at up to 130C continuously on some engines such as the BMW M3 (some) when worked hard. Over 130C is stretching the oil's operating envelope near it's limit. This is especially so with mineral oils that are not ACEA A3/B3 rated and are not Heavy Duty Engine Oils (HDEOs) as used in mixed fleets - diesel oils!
Generally the more expensive fully synthetic oils - especially those that are ACEA rated A3/B3 - have extremely good high temperature operational characteristics with low volatility and strong High Temperature High Shear (HTHS) vis. @150C (Porsche's minimum is 3.5) performance. HDEOs are rated differently (at higher duraility levels) and will operate very well in our engines especially those that are turbocharged as they have excellent deposit and corrosion control additives. These will have a CI-4/SL rating on the label
It is always important to use the correct viscosity oil for your car and this linkage may be of some interest to you;
http://www.landsharkoz.com/techtips.htm
Check under "Lubricants for the 928"
Sam - your comments are excellent. There is also a differential relief valve to protect the oil cooler and a differential by-pass valve in the oil filter to prevent damage to the filtering media and the filter as a whole. The by-pass is especially important with all oils when cold and especially the more viscous types - one good reason to always use a MANN or MAHLE filter. Our engines operate at very high pressure compared to most others. Until the oil is up to about 60C use engine revs above about 3000 rpm sparingly!
Regards
Last edited by Doug Hillary; 08-15-2004 at 03:12 AM.
