I ordered the Deso filters from www.sparkplugs.com and they were 1009's. The mobil filters were M-110's. You are clear, however is the Bypass valve is not open on either (don't know) than we have a media pressure issue, right? Denso seems to pride themself on their first time fit applications, and the fact the they are a very large OEM supplier. It seems that they would know the setting needed for the proper flow/pressure. In all fairness even though the car is a 2001 it has 205,000 miles on it. Oil pump probably weaker, but how weak, unknown. However, don't have the problem with the Mobil filter (no ticking anytime)
oil filter flow vs filtration
- Thread starter gulledge
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np with the nomenclature ..I just wanted to assure that we're on the same page when we swap things back and forth. What I say ..may not be what you hear ..so to speak.
As I said, I wouldn't not argue with Terry's assesment and the obvious remedy that occured with the swap in filters. He is extremely intelligent and has in depth experience. HLAs are odd devices that don't always follow normal reason for how they act. That is, there's a condition with them or your oil pump that makes a less restrictive media impact their performance during initial startup. You'll note that you don't hear bearing rumble or have any operational anomalies ..just ticking that's annoying as heck.
But, and as I assumed, your condition ONLY happens at initial startup. That is, a different filter doesn't apparently alter your flow in other mods of operation ..warm...second semiwarm start ..etc.
..and "normally" wouldn't do it at any other time either.
As Winston and I have batted back and forth. The ONLY time the filter media should impact flow is while the oil pump is in pressure relief ..otherwise the oil has no choice where it goes. That's not to say that HLA noise can't occur just because you're not in relief ..just that it can't be due to the filter media density if you aren't. Viscoisity and other issues are the cause if you're not (in relief).
Unless you're willing to install an aftermarket gauge, we won't know what pressure differences occur with different filters. I don't expect you to install one just to figure this out as I imagine that you're just happy that you don't have to deal with the HLA noise.
As I said, I wouldn't not argue with Terry's assesment and the obvious remedy that occured with the swap in filters. He is extremely intelligent and has in depth experience. HLAs are odd devices that don't always follow normal reason for how they act. That is, there's a condition with them or your oil pump that makes a less restrictive media impact their performance during initial startup. You'll note that you don't hear bearing rumble or have any operational anomalies ..just ticking that's annoying as heck.
But, and as I assumed, your condition ONLY happens at initial startup. That is, a different filter doesn't apparently alter your flow in other mods of operation ..warm...second semiwarm start ..etc.
..and "normally" wouldn't do it at any other time either.
As Winston and I have batted back and forth. The ONLY time the filter media should impact flow is while the oil pump is in pressure relief ..otherwise the oil has no choice where it goes. That's not to say that HLA noise can't occur just because you're not in relief ..just that it can't be due to the filter media density if you aren't. Viscoisity and other issues are the cause if you're not (in relief).
Unless you're willing to install an aftermarket gauge, we won't know what pressure differences occur with different filters. I don't expect you to install one just to figure this out as I imagine that you're just happy that you don't have to deal with the HLA noise.
I didn't see this mention so far ...
A more 'restrictive' media (Pure 1, M1) is acompanied by more media thus giving adequate flow. I would not hesitate to use them and have.
Now start-up rattle is another matter that was never associated with media until this thread. It was mostly was associate with bad ADBV, thick oil, things associated with oil starvation.
A more 'restrictive' media (Pure 1, M1) is acompanied by more media thus giving adequate flow. I would not hesitate to use them and have.
Now start-up rattle is another matter that was never associated with media until this thread. It was mostly was associate with bad ADBV, thick oil, things associated with oil starvation.
Gary,
I was using the word flow, when really I was meaning pressure. Does this help? Also the car is a 2001 Civic, no oil pressure gauge. The ticking sound did go away with the old Denso after 1-2 minutes or so. I am thinking this was an upper end pressure problem cause by the media. It just took a little longer for enough oil to reach the upper end at sufficient pressure. If the car had been running for a while and then was cut off, even for a couple of hours, upon start-up no ticking noise would be heard. Only on overnight or very long intervals would the ticking noise be heard just after start-up. If you still think I'm off base on this, why would Terry mention the term "Restrictive Filter" on a car with 3000 mile oil changes. I know there is a chance he was talking about the ADBV, but it would be hard for me to believe that every denso filter had the ADBV problem, as this problem went on for lots of oil changes using the Denso filters. However, the Mobil filter cured it, so it must have did something that is different about it with evidence it wasn't an ADBV issue. So lets talk "pressure" accross the media with a closed bypass valve. Sorry about the mixups in terms, as I typing and thinking at the same time. Is this better?
I was using the word flow, when really I was meaning pressure. Does this help? Also the car is a 2001 Civic, no oil pressure gauge. The ticking sound did go away with the old Denso after 1-2 minutes or so. I am thinking this was an upper end pressure problem cause by the media. It just took a little longer for enough oil to reach the upper end at sufficient pressure. If the car had been running for a while and then was cut off, even for a couple of hours, upon start-up no ticking noise would be heard. Only on overnight or very long intervals would the ticking noise be heard just after start-up. If you still think I'm off base on this, why would Terry mention the term "Restrictive Filter" on a car with 3000 mile oil changes. I know there is a chance he was talking about the ADBV, but it would be hard for me to believe that every denso filter had the ADBV problem, as this problem went on for lots of oil changes using the Denso filters. However, the Mobil filter cured it, so it must have did something that is different about it with evidence it wasn't an ADBV issue. So lets talk "pressure" accross the media with a closed bypass valve. Sorry about the mixups in terms, as I typing and thinking at the same time. Is this better?
Wavinwayne,
That M1-205 filter has a pressure activated outlet valve, that is what you see when you look in that exit hole. The oil coming into the filter through the inlet holes has enough pressure to force it open so oil flows through the filter while under pressure. When the flow stops, the valve closes and actually DOES keep the oil in the filter.
The adbv is sealing off the inlet holes, and that exit valve is sealing off the exit hole. That is why it won’t empty when you turn it upside down over a drain pan.
Gulledge,
I have read that the DENSO filters are short on media, like Frams are typically as well. Frams are notorious for causing startup valvetrain noise that will persist until the oil warms up and thins out enough to flow sufficiently to stop that noise. I had that characteristic symptom years ago until I learned about that here on BITOG. I changed brands of filters and the noise has never recurred. Any filter media has a certain flowrate per unit area, you saw that in the oil filter study. The more of that media you have the more flow you can have. The Denso just doesn’t have lots of media in the first place, the M1 has more media (and a different type as well) so it doesn’t have the flow issues that the DENSO does. A filter that has a very fine filtering media can cause some reduced flow particularly if it is a little short on total area, and definitely after it starts getting loaded up with debris. It can cause some back pressure and force the pump relief to shunt some oil back. And also, if the filter bypass is open, the bypass psid setting has been reached, so the pressure after the filter has already been reduced by that amount. That bypass will then close whenever the pressure drop across the filter decreases..like when the oil warms/thins up some for example..
Hope this helps
That M1-205 filter has a pressure activated outlet valve, that is what you see when you look in that exit hole. The oil coming into the filter through the inlet holes has enough pressure to force it open so oil flows through the filter while under pressure. When the flow stops, the valve closes and actually DOES keep the oil in the filter.
The adbv is sealing off the inlet holes, and that exit valve is sealing off the exit hole. That is why it won’t empty when you turn it upside down over a drain pan.
Gulledge,
I have read that the DENSO filters are short on media, like Frams are typically as well. Frams are notorious for causing startup valvetrain noise that will persist until the oil warms up and thins out enough to flow sufficiently to stop that noise. I had that characteristic symptom years ago until I learned about that here on BITOG. I changed brands of filters and the noise has never recurred. Any filter media has a certain flowrate per unit area, you saw that in the oil filter study. The more of that media you have the more flow you can have. The Denso just doesn’t have lots of media in the first place, the M1 has more media (and a different type as well) so it doesn’t have the flow issues that the DENSO does. A filter that has a very fine filtering media can cause some reduced flow particularly if it is a little short on total area, and definitely after it starts getting loaded up with debris. It can cause some back pressure and force the pump relief to shunt some oil back. And also, if the filter bypass is open, the bypass psid setting has been reached, so the pressure after the filter has already been reduced by that amount. That bypass will then close whenever the pressure drop across the filter decreases..like when the oil warms/thins up some for example..
Hope this helps
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ZR2RANDO,
Thanks for that explaination. Now I understand.
Thanks for that explaination. Now I understand.
first off let me step in and explain the pressure drops.
I put 40lbs on the inlet of each filter. that way I knew each filter had the same press on the input side of each filter. did the oil go into bypass mode of the oil pump? no, but if it did it would not affect the reading on the output side of the filter. the reading on the output side was the reading I got of the filter with 40lbs on the input side. did the adv open up. not likely as it would had shown up as very little difference between output and input. (except fram)
as for terrys comments, I agree, the adbv usually causes tap noise on the top end. that is why you should try a different filter. most don't know the difference between top and bottom end noise. Like someone said, sewing machine noise is top end. alot of gm's have the bottom end. most think it is the skirts of the pistons. the adbv will not fix this problem. the only other reason for top end tapping is valves out of adjustment.
as to Mobil 1. it is a very good filter. the only reason for it allowing oil to flow through the filter media is the oil press going through it.
when left a month upside down it has more than enough time to drain through the media as it has more that enough air in the center at the top. this will bypass the adbv, and will/should drain the oil out. but it doesn't. other filters do but not Mobil 1.
the media is like many, it has pores, what happend to these pores as heated oil passes through these pores? they fray and become expanded which then restrict even more. all filter pores do this. that is why they filter even better the older it gets.
another thing, why during oil analsys, the Mobil 1 filter has higher numbers than a cheap oil filter?
why when running no filter, thats right, no filter does it shows less wear on the oil analsys? why does a filter filter oil? it is there something in the oil? it doesn't keep it clean. If you have something in the oil, you have more serious problems than a filter will take out.
so what is better, filteration or flow? I'd rather have flow before filtation. with no oil, you have bearing problems, what happens with no filter?
I put 40lbs on the inlet of each filter. that way I knew each filter had the same press on the input side of each filter. did the oil go into bypass mode of the oil pump? no, but if it did it would not affect the reading on the output side of the filter. the reading on the output side was the reading I got of the filter with 40lbs on the input side. did the adv open up. not likely as it would had shown up as very little difference between output and input. (except fram)
as for terrys comments, I agree, the adbv usually causes tap noise on the top end. that is why you should try a different filter. most don't know the difference between top and bottom end noise. Like someone said, sewing machine noise is top end. alot of gm's have the bottom end. most think it is the skirts of the pistons. the adbv will not fix this problem. the only other reason for top end tapping is valves out of adjustment.
as to Mobil 1. it is a very good filter. the only reason for it allowing oil to flow through the filter media is the oil press going through it.
when left a month upside down it has more than enough time to drain through the media as it has more that enough air in the center at the top. this will bypass the adbv, and will/should drain the oil out. but it doesn't. other filters do but not Mobil 1.
the media is like many, it has pores, what happend to these pores as heated oil passes through these pores? they fray and become expanded which then restrict even more. all filter pores do this. that is why they filter even better the older it gets.
another thing, why during oil analsys, the Mobil 1 filter has higher numbers than a cheap oil filter?
why when running no filter, thats right, no filter does it shows less wear on the oil analsys? why does a filter filter oil? it is there something in the oil? it doesn't keep it clean. If you have something in the oil, you have more serious problems than a filter will take out.
so what is better, filteration or flow? I'd rather have flow before filtation. with no oil, you have bearing problems, what happens with no filter?
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BOBISTHEOILGUY,
You make very good points. The only other thing I have to add to this thread is this: Regardless of how restrictive the filter media is or isn't, in an M1-205 filter the oil WILL NOT drain out of it when it is removed from the car & turned upside down. This is because of the way the outlet valve in the filter is designed. ZR2RANDO explains this well 3 posts up. If you look into an M1-205 filter, it will be obvious why the oil won't drain out.
You make very good points. The only other thing I have to add to this thread is this: Regardless of how restrictive the filter media is or isn't, in an M1-205 filter the oil WILL NOT drain out of it when it is removed from the car & turned upside down. This is because of the way the outlet valve in the filter is designed. ZR2RANDO explains this well 3 posts up. If you look into an M1-205 filter, it will be obvious why the oil won't drain out.
why does it take pressure to get though the media? all the media has is pores right? the oil does not go all the way to the top. so why don't air get through the pores? what is stopping the air though the pores?
the adbv has nothing to do with the pores. it doesn't affect other filters. just that one.
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I will concede that the Mobil 1 filter media may be a bit more restrictive than the media found in other manufacturers' filters. But, I don't think it is enough to make any difference in the amount of oil getting to the engine. If anything, the more restrictive media keeps more oil in the filter when the engine is turned off, thus reducing the amount of time it takes for oil to get to vital engine parts upon start-up. At least that's the way I see it.
As a side note, the wear numbers from a recent 5100 mile UOA of mine in a VW 1.8T, using an Mobil 1-205 filter, were very, very low.
Filter Guy used to work for Champion Labs; maybe he could chime in with his take on all this.
As a side note, the wear numbers from a recent 5100 mile UOA of mine in a VW 1.8T, using an Mobil 1-205 filter, were very, very low.
Filter Guy used to work for Champion Labs; maybe he could chime in with his take on all this.
I simply don’t believe this can be true. If the pump wasn’t bypassing, four quarts of oil would disappear from the sump in less than 5 seconds. Not only would the pump be quickly starved, but I can’t believe the manufacturers would sacrifice the horsepower and fuel economy required to drive such high levels of oil flow through the engine.
Regarding oil staying in filters after they are removed from the engine…
Assuming air can get into the filter through the outlet hole, I believe the amount of oil that remains in an upside down filter is determined by the ADBV and construction of the filter at the open end. If the ADBV leaks, all the oil will leak out of the filter eventually (though it may take several days or weeks). It the ADBV is sound, the oil will drain down to a level determined by the internal construction of the filter at the open end. Filters with front end spring type bypass valves, such and the FL1A, will hold quite a bit of oil indefinitely if both the ADBV and bypass valves are sound. This is due to the high level the oil much reach to drain over the end of the bypass valve assembly.
Regarding oil pumps bypassing…
I haven’t seen any real data at this site with regard to when an oil pump is typically bypassing. There are lots of opinions and I thinks, but no real data. At this point, I wouldn’t be surprised if some engines using certain oils would go into bypass at oil temps as high as 80 degrees F. I also would suspect that, based on the pump bypass design, the bypass isn’t a very ideal one. That is, the pressure/flow characteristics would vary significantly with oil viscosity/temperature. The end result would be pump output pressure and flow into the filter varying with oil viscosity and temperature, enough that one could not always tell with certainty whether the oil pump is bypassing, even with a real oil pressure gauge.
As far as BITOG flow tests on filters from a couple years back…
Oil flow wasn’t measured, the oil was at room temperature, and the “circuit” after the filter wasn’t an engine. Therefore, IMO, the data isn’t very useful. We might be able to glean something useful from the data if we knew what real operating condition(s) it came close to simulating. But since we don’t appear to know enough about engine oil pump and bypass behavior over temperature with different oil viscosities, I don’t believe we can draw accurate conclusions.
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There is no "typical" data. They vary per installation.
Well, I wouldn't go that far. What do you qualify as "real data"
Wouldn't surprise me either. But it would not typically be by design.
I'm uncertain of what you mean here. Do you have a preferred method/modality?
Well, I'd rather say that pressure can vary with viscosity and temperature and therefore may alter flow by opening the relief.
Well, this takes a little thought here. Sure you could have a set of conditions that would allow reduced flow ..but they are rather narrow. Let's say ...you have an oil pump with 100 psi ..and you happen to get 88 psi with 0w-20. So ..as long as you read 100 psi ..you are getting the same flow to the engine. The variable is how much oil is getting sent back through the relief. Now take the same engine and throw 20w-50 in there ..and you'll be @ 100 MIN. and will be shunting oil probably all the time ..but the relief isn't a "full flow" mecanism ..you're 100 psi releif will not limit the pressure to 100 psi ..it will merely open at that pressure. I see this frequently in the winter with my HV oil pump. If I went with heavier oil ...I would further exceed that pressure relief.
Again, conditions and restriction apply.
Rando..great explaination on the M1-205 antidrain.
fwiw..it opens at .5 psi
BITOG..
I'm curious about your claim what good is a filter based on your experience when you ran without one and sent in an oil sample.
Are you saying that all these particle count beta tests when X amount of grams of contaminant is added to the fluid and sent through the filter and then counted downstream on the "clean" side of the filter.. the dirt went where?
Me thinks your mixing up two points. one is that engine companies , from my experience, say that particles in the 5-25 micron range cause the most wear within the engine.
Oil analysis counts particle much smaller than 5 microns. But the reason oil anaylsis is used is the "predictable" rate of the smaller particles within the oil. When your counts are higher = more engine wear. Lower = less.
I would have liked to have seen you try to run more than one sampling cycle without a filter and compare over time. The same thing oil analysis labs tell their customers, one sample is not condusive to determining the status of the engine.
Brian Barnhart
That is what I have been told by engineering types as to the flow rate of the oil (12-15 gpm)in some of the engines of today v years ago.
You can of course contact oil pump manufacturers and confirm or contact an OEM and see what they have to say as to whether or not there are those type of flows.
fwiw..it opens at .5 psi
BITOG..
I'm curious about your claim what good is a filter based on your experience when you ran without one and sent in an oil sample.
Are you saying that all these particle count beta tests when X amount of grams of contaminant is added to the fluid and sent through the filter and then counted downstream on the "clean" side of the filter.. the dirt went where?
Me thinks your mixing up two points. one is that engine companies , from my experience, say that particles in the 5-25 micron range cause the most wear within the engine.
Oil analysis counts particle much smaller than 5 microns. But the reason oil anaylsis is used is the "predictable" rate of the smaller particles within the oil. When your counts are higher = more engine wear. Lower = less.
I would have liked to have seen you try to run more than one sampling cycle without a filter and compare over time. The same thing oil analysis labs tell their customers, one sample is not condusive to determining the status of the engine.
Brian Barnhart
That is what I have been told by engineering types as to the flow rate of the oil (12-15 gpm)in some of the engines of today v years ago.
You can of course contact oil pump manufacturers and confirm or contact an OEM and see what they have to say as to whether or not there are those type of flows.
Flow is determined by the displacement of the pump X input RPM's (displacement x RPM). no matter what type of pump, gear, vane or piston.
1 cubic inch of displacement x 3000 RPM= 3000 cubic inches of oil per minute. 3000 cubic inches / 231 cubic inches per gallon = 12.987 gallons per minute of FLOW.
Pressure is dependent on resistance to flow. If you want to develop 100 PSI with the above pump you need to design a system with the necessary resistance.
If you DEADHEAD (provide no outlet for oil flow) a positive displacement pumping system. pressure will build until "something" gives or breaks. either the relief valve, the key on the pump input shaft, the pump housing, a hose, a seal etc. or the driving force stalls.
Oil systems operate the same as the hydraulics on your snow plow, log splitter, front end loader or hydraulic jack. Heck even the syringe the doc uses to give you a flu shot is a form of hydraulic pump. (scary huh?)
1 cubic inch of displacement x 3000 RPM= 3000 cubic inches of oil per minute. 3000 cubic inches / 231 cubic inches per gallon = 12.987 gallons per minute of FLOW.
Pressure is dependent on resistance to flow. If you want to develop 100 PSI with the above pump you need to design a system with the necessary resistance.
If you DEADHEAD (provide no outlet for oil flow) a positive displacement pumping system. pressure will build until "something" gives or breaks. either the relief valve, the key on the pump input shaft, the pump housing, a hose, a seal etc. or the driving force stalls.
Oil systems operate the same as the hydraulics on your snow plow, log splitter, front end loader or hydraulic jack. Heck even the syringe the doc uses to give you a flu shot is a form of hydraulic pump. (scary huh?)
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Hi, Pete!
You're coming in here with the train moving so to speak. What we're really looking into is how much a filter impacts flow. Now we've accepted (at least many have) that there is no altering of flow as long as the oil pump's relief isn't open. It doesn't matter. As you pointed out, with the exception of minor losses, "the flow is the flow" and it will figure its way through any choke or resistance as it has to ..period.
The main debate is ....how often is it in pressure relief. This can surely vary for a number of reasons.
My jeep OEM spec has a pressure relief of 75lb..yet regardless of viscosity (at least to the single digit temps I hit with 40 weight oil) ..the pressure never gets anywhere near that. So, one can infer that the volume and the relief don't necessarily have anything to do with each other in, at least, some installations. One is to limit the stress on the drive mechanisms ..the other is to provide a given volume at a given rpm.
Not all appear to be governed in this manner. I imagine that the crank driven oil pumps can endure more stress than our shaft/distributor driven types ..and relief limits can surely be used in other relationships with volume.
There are certain conditional givens that can't be ignored ..but prove to be "upset" in practice. For example we have a filter media that shouldn't present any interference with oil flow ..yet selecting a less resistive media relieves a symptom. This goes against our faith in certain givens. You then find out that the engine has 200k on it and probably has a weakened pressure relief ..or a worn oil pump that suffers more internal losses. That is, you've got to examine "apparent results" with a finer eye to view them properly.
This is why most things have to be qualified with "conditions and restrictions apply".
You're coming in here with the train moving so to speak. What we're really looking into is how much a filter impacts flow. Now we've accepted (at least many have) that there is no altering of flow as long as the oil pump's relief isn't open. It doesn't matter. As you pointed out, with the exception of minor losses, "the flow is the flow" and it will figure its way through any choke or resistance as it has to ..period.
The main debate is ....how often is it in pressure relief. This can surely vary for a number of reasons.
My jeep OEM spec has a pressure relief of 75lb..yet regardless of viscosity (at least to the single digit temps I hit with 40 weight oil) ..the pressure never gets anywhere near that. So, one can infer that the volume and the relief don't necessarily have anything to do with each other in, at least, some installations. One is to limit the stress on the drive mechanisms ..the other is to provide a given volume at a given rpm.
Not all appear to be governed in this manner. I imagine that the crank driven oil pumps can endure more stress than our shaft/distributor driven types ..and relief limits can surely be used in other relationships with volume.
There are certain conditional givens that can't be ignored ..but prove to be "upset" in practice. For example we have a filter media that shouldn't present any interference with oil flow ..yet selecting a less resistive media relieves a symptom. This goes against our faith in certain givens. You then find out that the engine has 200k on it and probably has a weakened pressure relief ..or a worn oil pump that suffers more internal losses. That is, you've got to examine "apparent results" with a finer eye to view them properly.
This is why most things have to be qualified with "conditions and restrictions apply".
It's all just basic hydraulic principals.
If you put a pressure gauge in line, before, the nozzle on the end of your garden hose and turn on the water. With the nozzle closed the gauge will read XX psi (xx 'cause different home water systems have different pressures). When you open the nozzle fully what happens to the gauge reading? It drops significantly. If you reduce the flow of water out of the nozzle what happens to the gauge reading? It rises.
Now lets remove the nozzle completly and replace it with an assortment of fittings and adapters until we end up with the same size copper tube that feeds the ice maker in the fridge. Turn the water on and you'll find out that with the 1/4" tube you have X psi in the hose and a very wet and mad wife sitting on the front porch 35 feet away.
Bypass (relief) valves open when their predetermined pressure settings are met or exceeded, regardless of pump flow. If your flow source meets enough resistance (clooged filter)in the system to restrict flow the pressure rises. When pressure rises flow does not increase. (See my last post, the only thing that will change the output of a fixed displacement pump is the input rpm.)
Filter bypass/relief valves use the differential pressure across the filter media to operate. Built in bypass/relief valves in the oil pump protect the pump and the down stream components from over pressurization and do not set system oil pressure. That is determined by the amount of resistance to flow downstream from the pump. Things such as oil passage surface conditions (smooth = less restriction) and size, journal/bearing clearances etc. If that resistance exceeds the filters bypass setting. The filters bypass will not open. if it exceeds the pumps relief setting that valve will open.
Filter bypasses (no matter what type or where located) open when the differential pressure is exceeded. No matter what the system pressure is. It's the pressure difference between the dirty side of the element and the clean side of the element that opens the bypass, be it a 3000 psi hydraulic system or a 45 psi engine lube system.
If you put a pressure gauge in line, before, the nozzle on the end of your garden hose and turn on the water. With the nozzle closed the gauge will read XX psi (xx 'cause different home water systems have different pressures). When you open the nozzle fully what happens to the gauge reading? It drops significantly. If you reduce the flow of water out of the nozzle what happens to the gauge reading? It rises.
Now lets remove the nozzle completly and replace it with an assortment of fittings and adapters until we end up with the same size copper tube that feeds the ice maker in the fridge. Turn the water on and you'll find out that with the 1/4" tube you have X psi in the hose and a very wet and mad wife sitting on the front porch 35 feet away.
Bypass (relief) valves open when their predetermined pressure settings are met or exceeded, regardless of pump flow. If your flow source meets enough resistance (clooged filter)in the system to restrict flow the pressure rises. When pressure rises flow does not increase. (See my last post, the only thing that will change the output of a fixed displacement pump is the input rpm.)
Filter bypass/relief valves use the differential pressure across the filter media to operate. Built in bypass/relief valves in the oil pump protect the pump and the down stream components from over pressurization and do not set system oil pressure. That is determined by the amount of resistance to flow downstream from the pump. Things such as oil passage surface conditions (smooth = less restriction) and size, journal/bearing clearances etc. If that resistance exceeds the filters bypass setting. The filters bypass will not open. if it exceeds the pumps relief setting that valve will open.
Filter bypasses (no matter what type or where located) open when the differential pressure is exceeded. No matter what the system pressure is. It's the pressure difference between the dirty side of the element and the clean side of the element that opens the bypass, be it a 3000 psi hydraulic system or a 45 psi engine lube system.
Pete,
Oops you jumped in as I was writing this message (edit)
Thanks for chiming in. As you point out flow on an engine oil pump is dependant on rpm. Since a typical engine varies from 750 to 6000 rpm, the flow rate will vary greatly. Is your example of 12.987 gpm at 3000rpm common?
I wish we knew what conditions will cause a typical oil pump relief valve to open;
At idle with 5W30 oil at 30deg F? Above 4000rpm with 5W30 oil at 150deg F? Hmmm. The answers are out there....
Oops you jumped in as I was writing this message (edit)
Thanks for chiming in. As you point out flow on an engine oil pump is dependant on rpm. Since a typical engine varies from 750 to 6000 rpm, the flow rate will vary greatly. Is your example of 12.987 gpm at 3000rpm common?
I wish we knew what conditions will cause a typical oil pump relief valve to open;
At idle with 5W30 oil at 30deg F? Above 4000rpm with 5W30 oil at 150deg F? Hmmm. The answers are out there....
From Gary
Lets, see if Pete will back me up on this. He is very good at explaining things. His last post was very clear.
I still maintain that if the pump relief valve is open, the filter restriction will affect the flow to the engine, but that is the only time the filter restriction will affect flow to the engine.
Lets, see if Pete will back me up on this. He is very good at explaining things. His last post was very clear.
I'm not trying to preach just teach.
Maybe this is where I'll get myself booted off this forum but here goes.
I'm trying to provide simple easy to unterstand examples. This whole relief valve bypass thing is not as complicated as Ya'll want it to be.
Anything that you put into the flow stream of any medium, (oil, air, sugar), will create a pressure spike on the up stream (pump)side of the system. When you remove that restriction there is a pressure drop upstream. but in either case the spike and the drop are momentary. as long as there is still flow.
Take a standard oil filter with a, for arguements sake, 10 psi bypass valve, and hook it into to the previous hose and nozzle arangement with the pressure gauge on the inlet side and add another gauge on the outlet side and then the nozzle.
Let's assume that our household water pressure is a nice 30 psi.
Open the nozzle and turn on the spigot at the house. When the air has left the system stop the flow with the nozzle. Both pressure gauges will read 30 psi. Open the nozzle and there will be an instant pressure difference fron one side of the media to the other. If this difference exceeds the setting (10 psi) of the filters bypass, it will open, and stay open until both pressures equalize to a point less than the valves setting (9.9999 psi in theory).
If the pumps relief valve should open it is relieving pressure by bypassing flow into the suction port of the pump. Which in turn reduces flow into the system. The pump only knows that it was designed to put out a predetermined amount of flow at 1 rpm, and that's what it does. The flow output of the pump does not change. System designers determine how fast to spin that pump to get a minimum amout of flow to prevent damage to bearings etc.
In the case of cold startups the oil "burns" across the pumps relief valve which causes the oil to heat up before it even gets to the filter. Some of this warmer oil is recirculated back to the pump and helps heat up the colder oil being sucked into the pump. Meanwhile down stream in the filter, that first movement of cold oil has created a differential pressure between the clean and dirty side of the element. It's harder to push that thick oil through the media as we all know, so the bypass sensing this difference, and feeling sorry for the bearing surfaces, opens up to let that cold oil flow through.
The pump relief valve, sensing this larger flow path closes, increasing the flow into the filter. The filter is now getting thinner warmer oil and the differential pressure drops. The bypass valve closes and now all the oil is passing through the filter media.
Relief and bypass valves do not open to full capacity in every instance of use they open Just enough to correct the condition they were designed to correct. They may crack open a a few thousandths or 1/8" depending on conditions.
Total time, between 5 and 20 seconds on a real cold sub zero morning. About the same for a balmy 80 degree morning here in the south.
[ June 01, 2005, 01:54 PM: Message edited by: Pete C. ]
Maybe this is where I'll get myself booted off this forum but here goes.
I'm trying to provide simple easy to unterstand examples. This whole relief valve bypass thing is not as complicated as Ya'll want it to be.
Anything that you put into the flow stream of any medium, (oil, air, sugar), will create a pressure spike on the up stream (pump)side of the system. When you remove that restriction there is a pressure drop upstream. but in either case the spike and the drop are momentary. as long as there is still flow.
Take a standard oil filter with a, for arguements sake, 10 psi bypass valve, and hook it into to the previous hose and nozzle arangement with the pressure gauge on the inlet side and add another gauge on the outlet side and then the nozzle.
Let's assume that our household water pressure is a nice 30 psi.
Open the nozzle and turn on the spigot at the house. When the air has left the system stop the flow with the nozzle. Both pressure gauges will read 30 psi. Open the nozzle and there will be an instant pressure difference fron one side of the media to the other. If this difference exceeds the setting (10 psi) of the filters bypass, it will open, and stay open until both pressures equalize to a point less than the valves setting (9.9999 psi in theory).
If the pumps relief valve should open it is relieving pressure by bypassing flow into the suction port of the pump. Which in turn reduces flow into the system. The pump only knows that it was designed to put out a predetermined amount of flow at 1 rpm, and that's what it does. The flow output of the pump does not change. System designers determine how fast to spin that pump to get a minimum amout of flow to prevent damage to bearings etc.
In the case of cold startups the oil "burns" across the pumps relief valve which causes the oil to heat up before it even gets to the filter. Some of this warmer oil is recirculated back to the pump and helps heat up the colder oil being sucked into the pump. Meanwhile down stream in the filter, that first movement of cold oil has created a differential pressure between the clean and dirty side of the element. It's harder to push that thick oil through the media as we all know, so the bypass sensing this difference, and feeling sorry for the bearing surfaces, opens up to let that cold oil flow through.
The pump relief valve, sensing this larger flow path closes, increasing the flow into the filter. The filter is now getting thinner warmer oil and the differential pressure drops. The bypass valve closes and now all the oil is passing through the filter media.
Relief and bypass valves do not open to full capacity in every instance of use they open Just enough to correct the condition they were designed to correct. They may crack open a a few thousandths or 1/8" depending on conditions.
Total time, between 5 and 20 seconds on a real cold sub zero morning. About the same for a balmy 80 degree morning here in the south.
[ June 01, 2005, 01:54 PM: Message edited by: Pete C. ]
Pete, you got in ahead of me again. Great explanation by the way. (edit)
Let me give my explanation. Like Pete says it is a hydraulics problem. The oil pressure relief opens because there is enough resistance downstream to cause the pressure to exceed the relief setting. The resistance that the relief valve sees is the sum of all the resistance components in the oil system(there are some parrallel paths so it is not straight addition). Those components include the roughness of the oil passages, the bearings, etc, and the oil filter.
So, yes, the resistance of the oil filter affects when the oil pump relief valve opens. Higher filter resistance would mean that the oil pump relief valve would be open more often.
[ June 01, 2005, 02:00 PM: Message edited by: Winston ]
Ah Ha. I always wondered how the oil could heat up so quickly. It never seemed to me that the heat of combustion could warm the oil in 5-10sec.
The filter is a contributor to flow divergence(I do not like that term, but I know what you are saying)
Let me give my explanation. Like Pete says it is a hydraulics problem. The oil pressure relief opens because there is enough resistance downstream to cause the pressure to exceed the relief setting. The resistance that the relief valve sees is the sum of all the resistance components in the oil system(there are some parrallel paths so it is not straight addition). Those components include the roughness of the oil passages, the bearings, etc, and the oil filter.
So, yes, the resistance of the oil filter affects when the oil pump relief valve opens. Higher filter resistance would mean that the oil pump relief valve would be open more often.
[ June 01, 2005, 02:00 PM: Message edited by: Winston ]
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