[Z06] Dry Sump Question
07-21-2009, 12:46 AM
#1
Burning Brakes
Thread Starter
Dry Sump Question
I have read here that overfilling the oil tank can cause major engine damage. Not really understanding the details of how the system works, other than the obvious, why would too much oil in the tank cause damage? Isn't it simply a storage tank that supplies oil to a pump that delivers oil to the engine and then recycles the oil back through the tank?? So why would too much oil in the tank cause a catastrophe? Sorry for the dumb question, but I am just new to Z06's and dry sump oil systems. Thanks.
07-21-2009, 02:51 AM
#2
I have read here that overfilling the oil tank can cause major engine damage. Not really understanding the details of how the system works, other than the obvious, why would too much oil in the tank cause damage? Isn't it simply a storage tank that supplies oil to a pump that delivers oil to the engine and then recycles the oil back through the tank?? So why would too much oil in the tank cause a catastrophe? Sorry for the dumb question, but I am just new to Z06's and dry sump oil systems. Thanks.
It's not the overfill of the tank that's a problem, it's the collection of oil in the pan faster than it can be scavenged back to the tank.
Then you have the same problems as a wet-sump, in order of decreasing likeliness:
1. Increased windage.
2. Burning oil from poor piston ring seal.
3. Fouled plugs from #2
4. Increased blow-by from #2
5. Frothing of the oil from #1 and possible submerged crank. This is bad.
6. Possibly blowing out a line or the oil filter from excessive pressure?
Hope this isn't too far off base.
07-21-2009, 07:10 AM
#3
I have read here that overfilling the oil tank can cause major engine damage. Not really understanding the details of how the system works, other than the obvious, why would too much oil in the tank cause damage? Isn't it simply a storage tank that supplies oil to a pump that delivers oil to the engine and then recycles the oil back through the tank?? So why would too much oil in the tank cause a catastrophe? Sorry for the dumb question, but I am just new to Z06's and dry sump oil systems. Thanks.
The tank in a dry sump lubrication system really performs two tasks. Firstly the obvious - storing the engine oil and maintaining a supply of good quality feed stock for the oil pump.
Secondly - the tank has to deal with the returned oil, scavenged from the engine, and , as it were, 'process' it for further use.
Process it in a 'physical' way that is - not chemical!
As it passes through the lubrication system, gasses[air, etc]become entrained in the oil, and these need to be separated out from the oil, before it is resupplied to the engine.
That's the tank's secondary task.
It is however vital that it performs this task effectively - as is well documented is these forums - air+oil = not a good recipe for healthy crankshaft bearings
.The tank acts as a 'knockout pot' - it de-aerates the scavenged oil returned from the engine.
The returning oil cascades down the tank and the entrained gasses expand and flash off, leaving the oil fit for reuse.
At least that's what's supposed to happen!
In the lefthand picture you can see the supply and return lines from the pump/sump entering and exiting at the bottom of the oil tank.
On top of the tank between the dipstick and the oil filler cap, you can see the tank vent lines -One of these lines is supplied with clean air sourced from upside of the throttleplate - this air enters the tank, mixes with the gases leaving the oil, and the ensuing mixture of gases escapes down the other line into the rocker boxes and on into the vehicles Positive Crankcase Ventilation System.
In the righthand picture you can see the internals of the oil tank.
At the bottom you can see the gauze strainer set into the tank for the pump feed supply - the other item just protruding into the bottom of the tank is the engine oil temperature sensor.
You can see how the scavenged oil returned from the engine to the tank, is routed up into an internal pipe, and allowed to exit into the top half of the tank, thence to cascade down inside the tank, allowing the gas to flash off.
Hopefully you can now see what will happen if you really overfill the tank!
At worst you will impede the returning flow of the scavenged oil - you will leave little space for effective de-aeration of this returning oil,thus degrade the quality of the feedstock.
You will also have foamng in the top half of the tank leaving the distinct possibility of liquid being drawn over into the PCV system!
Not a good idea to overfil the tank
07-21-2009, 12:33 PM
#4
It depends on how much extra oil is in there. If it's 1/4 quart, you are fine. If it's 2.5 quarts look out (this can easily happen if someone checks and adds oil after the car has been sitting for awhile and the oil is in the pan; a GM tech did it to mine). When the car is started, the scavenge pump pulls the oil from the pan and into a tank that is already full (from the overfill). That extra oil can only escape through the vent line from the top of the tank into the intake bridge. If it is a small amount you're OK, if it's alot, you could hyrolock your motor.
Luckily I was there when it was fired up and started yelling as soon as it started smoking. We pulled the intake (full of oil) and pulled the plugs to give the oil a place to escape. Two of the cylinders had ALOT of oil in them. The motor let go 3 days later and the official diagnosis was a weak casting in the factory piston, but I'm sure this had something to do with it, and since my car was modded, no warranty. Nice of them, don't you think?
Luckily I was there when it was fired up and started yelling as soon as it started smoking. We pulled the intake (full of oil) and pulled the plugs to give the oil a place to escape. Two of the cylinders had ALOT of oil in them. The motor let go 3 days later and the official diagnosis was a weak casting in the factory piston, but I'm sure this had something to do with it, and since my car was modded, no warranty. Nice of them, don't you think?
07-21-2009, 12:41 PM
#5
Melting Slicks
It depends on how much extra oil is in there. If it's 1/4 quart, you are fine. If it's 2.5 quarts look out (this can easily happen if someone checks and adds oil after the car has been sitting for awhile and the oil is in the pan; a GM tech did it to mine). When the car is started, the scavenge pump pulls the oil from the pan and into a tank that is already full (from the overfill). That extra oil can only escape through the vent line from the top of the tank into the intake bridge. If it is a small amount you're OK, if it's alot, you could hyrolock your motor.
Luckily I was there when it was fired up and started yelling as soon as it started smoking. We pulled the intake (full of oil) and pulled the plugs to give the oil a place to escape. Two of the cylinders had ALOT of oil in them. The motor let go 3 days later and the official diagnosis was a weak casting in the factory piston, but I'm sure this had something to do with it, and since my car was modded, no warranty. Nice of them, don't you think?
Luckily I was there when it was fired up and started yelling as soon as it started smoking. We pulled the intake (full of oil) and pulled the plugs to give the oil a place to escape. Two of the cylinders had ALOT of oil in them. The motor let go 3 days later and the official diagnosis was a weak casting in the factory piston, but I'm sure this had something to do with it, and since my car was modded, no warranty. Nice of them, don't you think?
And if its a small amount it will run down the bottom of the snorkel, loosen the glue that holds on the paper carbon trap and result in it coming loose and getting sucked into the intake.........and then continue on down and soak your $200 paper air filter with oil
07-21-2009, 09:53 PM
#6
Le Mans Master
Member Since: May 2007
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Certainly not a dumb question at all!
The tank in a dry sump lubrication system really performs two tasks. Firstly the obvious - storing the engine oil and maintaining a supply of good quality feed stock for the oil pump.
Secondly - the tank has to deal with the returned oil, scavenged from the engine, and , as it were, 'process' it for further use.
Process it in a 'physical' way that is - not chemical!
As it passes through the lubrication system, gasses[air, etc]become entrained in the oil, and these need to be separated out from the oil, before it is resupplied to the engine.
That's the tank's secondary task.
It is however vital that it performs this task effectively - as is well documented is these forums - air+oil = not a good recipe for healthy crankshaft bearings.
The tank acts as a 'knockout pot' - it de-aerates the scavenged oil returned from the engine.
The returning oil cascades down the tank and the entrained gasses expand and flash off, leaving the oil fit for reuse.
At least that's what's supposed to happen!
In the lefthand picture you can see the supply and return lines from the pump/sump entering and exiting at the bottom of the oil tank.
On top of the tank between the dipstick and the oil filler cap, you can see the tank vent lines -One of these lines is supplied with clean air sourced from upside of the throttleplate - this air enters the tank, mixes with the gases leaving the oil, and the ensuing mixture of gases escapes down the other line into the rocker boxes and on into the vehicles Positive Crankcase Ventilation System.
In the righthand picture you can see the internals of the oil tank.
At the bottom you can see the gauze strainer set into the tank for the pump feed supply - the other item just protruding into the bottom of the tank is the engine oil temperature sensor.
You can see how the scavenged oil returned from the engine to the tank, is routed up into an internal pipe, and allowed to exit into the top half of the tank, thence to cascade down inside the tank, allowing the gas to flash off.
Hopefully you can now see what will happen if you really overfill the tank!
At worst you will impede the returning flow of the scavenged oil - you will leave little space for effective de-aeration of this returning oil,thus degrade the quality of the feedstock.
You will also have foamng in the top half of the tank leaving the distinct possibility of liquid being drawn over into the PCV system!
Not a good idea to overfil the tank
The tank in a dry sump lubrication system really performs two tasks. Firstly the obvious - storing the engine oil and maintaining a supply of good quality feed stock for the oil pump.
Secondly - the tank has to deal with the returned oil, scavenged from the engine, and , as it were, 'process' it for further use.
Process it in a 'physical' way that is - not chemical!
As it passes through the lubrication system, gasses[air, etc]become entrained in the oil, and these need to be separated out from the oil, before it is resupplied to the engine.
That's the tank's secondary task.
It is however vital that it performs this task effectively - as is well documented is these forums - air+oil = not a good recipe for healthy crankshaft bearings
.The tank acts as a 'knockout pot' - it de-aerates the scavenged oil returned from the engine.
The returning oil cascades down the tank and the entrained gasses expand and flash off, leaving the oil fit for reuse.
At least that's what's supposed to happen!
In the lefthand picture you can see the supply and return lines from the pump/sump entering and exiting at the bottom of the oil tank.
On top of the tank between the dipstick and the oil filler cap, you can see the tank vent lines -One of these lines is supplied with clean air sourced from upside of the throttleplate - this air enters the tank, mixes with the gases leaving the oil, and the ensuing mixture of gases escapes down the other line into the rocker boxes and on into the vehicles Positive Crankcase Ventilation System.
In the righthand picture you can see the internals of the oil tank.
At the bottom you can see the gauze strainer set into the tank for the pump feed supply - the other item just protruding into the bottom of the tank is the engine oil temperature sensor.
You can see how the scavenged oil returned from the engine to the tank, is routed up into an internal pipe, and allowed to exit into the top half of the tank, thence to cascade down inside the tank, allowing the gas to flash off.
Hopefully you can now see what will happen if you really overfill the tank!
At worst you will impede the returning flow of the scavenged oil - you will leave little space for effective de-aeration of this returning oil,thus degrade the quality of the feedstock.
You will also have foamng in the top half of the tank leaving the distinct possibility of liquid being drawn over into the PCV system!
Not a good idea to overfil the tank
07-21-2009, 10:11 PM
#7
Burning Brakes
Thread Starter
Certainly not a dumb question at all!
The tank in a dry sump lubrication system really performs two tasks. Firstly the obvious - storing the engine oil and maintaining a supply of good quality feed stock for the oil pump.
Secondly - the tank has to deal with the returned oil, scavenged from the engine, and , as it were, 'process' it for further use.
Process it in a 'physical' way that is - not chemical!
As it passes through the lubrication system, gasses[air, etc]become entrained in the oil, and these need to be separated out from the oil, before it is resupplied to the engine.
That's the tank's secondary task.
It is however vital that it performs this task effectively - as is well documented is these forums - air+oil = not a good recipe for healthy crankshaft bearings.
The tank acts as a 'knockout pot' - it de-aerates the scavenged oil returned from the engine.
The returning oil cascades down the tank and the entrained gasses expand and flash off, leaving the oil fit for reuse.
At least that's what's supposed to happen!
In the lefthand picture you can see the supply and return lines from the pump/sump entering and exiting at the bottom of the oil tank.
On top of the tank between the dipstick and the oil filler cap, you can see the tank vent lines -One of these lines is supplied with clean air sourced from upside of the throttleplate - this air enters the tank, mixes with the gases leaving the oil, and the ensuing mixture of gases escapes down the other line into the rocker boxes and on into the vehicles Positive Crankcase Ventilation System.
In the righthand picture you can see the internals of the oil tank.
At the bottom you can see the gauze strainer set into the tank for the pump feed supply - the other item just protruding into the bottom of the tank is the engine oil temperature sensor.
You can see how the scavenged oil returned from the engine to the tank, is routed up into an internal pipe, and allowed to exit into the top half of the tank, thence to cascade down inside the tank, allowing the gas to flash off.
Hopefully you can now see what will happen if you really overfill the tank!
At worst you will impede the returning flow of the scavenged oil - you will leave little space for effective de-aeration of this returning oil,thus degrade the quality of the feedstock.
You will also have foamng in the top half of the tank leaving the distinct possibility of liquid being drawn over into the PCV system!
Not a good idea to overfil the tank
The tank in a dry sump lubrication system really performs two tasks. Firstly the obvious - storing the engine oil and maintaining a supply of good quality feed stock for the oil pump.
Secondly - the tank has to deal with the returned oil, scavenged from the engine, and , as it were, 'process' it for further use.
Process it in a 'physical' way that is - not chemical!
As it passes through the lubrication system, gasses[air, etc]become entrained in the oil, and these need to be separated out from the oil, before it is resupplied to the engine.
That's the tank's secondary task.
It is however vital that it performs this task effectively - as is well documented is these forums - air+oil = not a good recipe for healthy crankshaft bearings
.The tank acts as a 'knockout pot' - it de-aerates the scavenged oil returned from the engine.
The returning oil cascades down the tank and the entrained gasses expand and flash off, leaving the oil fit for reuse.
At least that's what's supposed to happen!
In the lefthand picture you can see the supply and return lines from the pump/sump entering and exiting at the bottom of the oil tank.
On top of the tank between the dipstick and the oil filler cap, you can see the tank vent lines -One of these lines is supplied with clean air sourced from upside of the throttleplate - this air enters the tank, mixes with the gases leaving the oil, and the ensuing mixture of gases escapes down the other line into the rocker boxes and on into the vehicles Positive Crankcase Ventilation System.
In the righthand picture you can see the internals of the oil tank.
At the bottom you can see the gauze strainer set into the tank for the pump feed supply - the other item just protruding into the bottom of the tank is the engine oil temperature sensor.
You can see how the scavenged oil returned from the engine to the tank, is routed up into an internal pipe, and allowed to exit into the top half of the tank, thence to cascade down inside the tank, allowing the gas to flash off.
Hopefully you can now see what will happen if you really overfill the tank!
At worst you will impede the returning flow of the scavenged oil - you will leave little space for effective de-aeration of this returning oil,thus degrade the quality of the feedstock.
You will also have foamng in the top half of the tank leaving the distinct possibility of liquid being drawn over into the PCV system!
Not a good idea to overfil the tank
