LSJr tests oil filter BP function ... "OIL FILTERS: What most people DON'T know"
- Thread starter dnewton3
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I thought the dp was across the media only, once it gets to the inside the pressure would be according to the size of those pipes downstream. Since flow is assumed constant at an rpm.
But now there's "bickering" in this thread about what words aren't allowed on BITOG, not even related to bickering about technical discussions, lol.
Haven't watched this video yet, but might be back to bicker it technically.
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Where is the Allen study? Btw I heard no bad words in this video, maybe missed it. I don’t think they did this right.
I posted some links above.
LSJr's co-pilot said:
"Anything smaller than about 25 microns will go through the system without hurting."
This is not what many engine wear studies conclude. Those studies say that the most wear from debris in the oil is from particles less than 20 microns in size because those are the ones that can get between moving parts with very small film thickness between the parts. If particles can't get between moving parts, then they can't do damage. Of course, some larger particles may get between larger gaps, get crushed up and them become more smaller particles than can then start getting between tight moving parts.
He calls the rubber ADBV a "plastic valve", which it's not plastic. He should have done a burn test, lol. Yes, it could be considered a one-way "check valve". He also implies that the ADBV is only important when the filter is mounted horizontally, but not base up vertically. That's an on-going misconception because the ADBV on a base up vertical orientated filter will keep the oil in the galleries above the filter from draining down back through the filter.
What they should have clarified is that when the bypass valve opens that there is still lots of oil still also flowing through the oil filter media at the same time. Some people seem to believe when it opens that all the oil then goes through the bypass valve, but it doesn't work that way. The only time all oil would go through the bypass valve is if the media was 100% clogged.
He said the "only time that happens" (meaning the bypass valve opens) is when the filter is totally clogged. That's not true, as the bypass valve can open on cold starts if the oil is cold and thick enough and the engine RPM is high enough. Even if the oil was fully hot and the oil pump was some high output volume pump with a high pressure relief setting, it could be flowing enough oil through the filter to cause enough dP across the media to make the bypass valve open if it was set pretty low.
Engine 1700 RPM with oil "cold". He doesn't show or say what the oil temp was, but at room temp before start-up, so probably around 70F. Engine speed it 1700 and dP across the filter is 0.7 PSI since the engine RPM is low and oil flow low. No surprise there.
1st dyno run the hot oil temp at 100C (can see it on the screen). The max dP across the filter was around 6-7 PSI which is no surprise with fully hot oil. And I'd bet that engine doesn't really have a super high volume oil pump - probably max pump flow is around 8 GPM.
They never did a dyno pull to full RPM with cold oil, only hot from what I'm seeing so no surprise they didn't see a dP across the filter high enough to open the bypass valve. Jim Allen's on vehicle filter dP testing showed many bypass opening events when the oil was much colder than room temperature and engine RPM was well above idle speed. Put that dyno test out in a building at 20F, fire it up cold and do a dyno pull to redline and that filter will definitely go into bypass. As always, if you don't want the oil filter possibly going into bypass after a cold start, let the oil warm up a bit and keep the RPM low before going gonzo until the oil is near full operating temperature.
He said as the oil was warming up the dP across the filter was increasing (ref time 8:48). I say no way on that one - something is off there. If the oil becomes thinner and the flow rate stays the same through the filter, then the dP across the media will be lower - there is no physical way it would be higher. What's going on inside the engine after the filter has no bearing on the dP across the filter. The dP across the filter is solely a function of the oil viscosity and flow rate through the media.
Comments on YT to the video shows that:
Many people don't understand oil filters.
Many people don't understand engine oiling systems.
"Anything smaller than about 25 microns will go through the system without hurting."
This is not what many engine wear studies conclude. Those studies say that the most wear from debris in the oil is from particles less than 20 microns in size because those are the ones that can get between moving parts with very small film thickness between the parts. If particles can't get between moving parts, then they can't do damage. Of course, some larger particles may get between larger gaps, get crushed up and them become more smaller particles than can then start getting between tight moving parts.
He calls the rubber ADBV a "plastic valve", which it's not plastic. He should have done a burn test, lol. Yes, it could be considered a one-way "check valve". He also implies that the ADBV is only important when the filter is mounted horizontally, but not base up vertically. That's an on-going misconception because the ADBV on a base up vertical orientated filter will keep the oil in the galleries above the filter from draining down back through the filter.
What they should have clarified is that when the bypass valve opens that there is still lots of oil still also flowing through the oil filter media at the same time. Some people seem to believe when it opens that all the oil then goes through the bypass valve, but it doesn't work that way. The only time all oil would go through the bypass valve is if the media was 100% clogged.
He said the "only time that happens" (meaning the bypass valve opens) is when the filter is totally clogged. That's not true, as the bypass valve can open on cold starts if the oil is cold and thick enough and the engine RPM is high enough. Even if the oil was fully hot and the oil pump was some high output volume pump with a high pressure relief setting, it could be flowing enough oil through the filter to cause enough dP across the media to make the bypass valve open if it was set pretty low.
Engine 1700 RPM with oil "cold". He doesn't show or say what the oil temp was, but at room temp before start-up, so probably around 70F. Engine speed it 1700 and dP across the filter is 0.7 PSI since the engine RPM is low and oil flow low. No surprise there.
1st dyno run the hot oil temp at 100C (can see it on the screen). The max dP across the filter was around 6-7 PSI which is no surprise with fully hot oil. And I'd bet that engine doesn't really have a super high volume oil pump - probably max pump flow is around 8 GPM.
They never did a dyno pull to full RPM with cold oil, only hot from what I'm seeing so no surprise they didn't see a dP across the filter high enough to open the bypass valve. Jim Allen's on vehicle filter dP testing showed many bypass opening events when the oil was much colder than room temperature and engine RPM was well above idle speed. Put that dyno test out in a building at 20F, fire it up cold and do a dyno pull to redline and that filter will definitely go into bypass. As always, if you don't want the oil filter possibly going into bypass after a cold start, let the oil warm up a bit and keep the RPM low before going gonzo until the oil is near full operating temperature.
He said as the oil was warming up the dP across the filter was increasing (ref time 8:48). I say no way on that one - something is off there. If the oil becomes thinner and the flow rate stays the same through the filter, then the dP across the media will be lower - there is no physical way it would be higher. What's going on inside the engine after the filter has no bearing on the dP across the filter. The dP across the filter is solely a function of the oil viscosity and flow rate through the media.
Comments on YT to the video shows that:
Many people don't understand oil filters.
Many people don't understand engine oiling systems.
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Exactly, if he doesn't comprehend that then one has to wonder what he really does.
Yes, that's been a long on-going misconception that an ADBV doesn't matter if the filter is mounted base up and vertical.
AZjeff
$50 Site Donor 2023
Where the dyno guy says we tried to ruin this "darn" engine almost at the end. Missed it too.
So this video is full of fake news? ADBV and bypass events?
It just showed that if the oil is warm enough on an engine with a pretty low volume oil pump that the dP across the filter won't be enough to cause it to bypass. Do that same max RPM dyno pull with the oil at 20F and it would go into bypass for sure. They don't really touch on that much, and leave the audience thinking (and ready to go start spreading misinformation, lol) that oil filters never go into bypass unless they are nearly totally clogged ... which isn't a true statement. If the oil is cold enough, the bypass valve setting low enough and the engine RPM high enough the filter will bypass.
wemay
Site Donor 2023
Just viewed. Thought it was another good video from Lake.
Even if they would have done the dyno run to redline with room temperature oil (which they didn't do) the filter would probably have hit bypass dP.
You must account for the outlet restriction presented by the engine. I didn't look at the rig or the video but the ΔP would of course be the mains drill feed pressure minus the oil pump outlet pressure. There could be an empty can on the filter boss or a can loaded with a media cartridge, or media cartridge with bypass poppet combination. Or simply a length of tubing smaller than the outlet but larger than the mains drill feed.
I mention pressure and not volume flow, as the filter will be presented with a constant pressure at the filter inlet as rpm rise, since the oil pump should be now operating in bypass at mid/high rpm. If the "protection" of the oil pump bypass becomes compromised (no bypass) and flow is increasing with engine RPM, the ΔP approaches the burst pressure of the filter can/gasket design limit and you will either blow open the filter can crimp or, more often, blow out the base gasket and dump oil all over the track. If outlet drill size and flow was unencumbered or non critical, this would not occur.
Taking the setup and the calculus to limits: Fully Restricted outlet = No volume flow = No delta; an Unrestricted outlet = max flow = Max delta - as the intermediate restriction presents itself fully.
Again, I did not watch the video yet and I am blind to engine rpm and their pump bypass setting. So I can't question why one would ignore or dismiss the actual test gauge reading " ... as something is off there". I don't even know the engine used in this video, but an unrestricted SBC factory pump is typ 15gal/min at mid operational rpm. Another consideration, Multi Vis motor oil exhibits Non-Newtonian fluid properties, but I would largely ignore that on this simple exercise. - Arco
You should probably watch the video before trying to talk about the video.
Like said, what's going on after the oil filter does not effect what's going on across the filter. You could mount that filter on a test rig in a laboratory and conduct a dP vs flow test. It's done all the time per the ISO 4548 test. Look at Ascent's dP vs flow and even BR on YT dP vs flow tests. In this case, the engine was the test rig. They simply had a pressure gauge before and after the oil filter. They didn't measure oil viscosity, but simply said the oil was either cold or hot. You can see on the data screen it was around 100C when hot. "Cold" was whatever room temperature was in the dyno room .. so call it 65-70F. So if the two pressure sensors they used were located in big oil galleries before and after the filter, then for all practical purposes they were measuring the dP across the filter.
The PD oil pump like used on the GM LS will still increase volume output and therefore pressure even after the spring loaded bypass valve starts opening. In fact, that pump will start going into pressure relief well before redline, but the flow to the engine and hence the pressure will still increase at a lower rate as RPM increases.
Yes, for the overall oiling system ... but again, what's going on just across the oil can be looked at regardless of how the overall oiling system reacts to the restriction of the oiling system as a whole. They were trying to use the engine as an "oil filter dP vs flow test rig" without full instrumentation.
As covered above, the flow is not unrestricted when the pump is on an engine. The OEM LS oil pump only puts out around 7-8 GPM at redline. They didn't say what pump was on the engine (stock or aftermarket), but even an aftermarket pump like an aftermarket Melling doesn't put out much more than 10-12 GPM when on the engine depending on what pressure relief spring is used in the pump.
When they claimed the dP across the oil filter was increasing as the oil warmed up (ref time 8:48), there's no way that could physically happen unless something else was going on with the test setup that they didn't understand or didn't divulge that could cause that to happen. When someone can prove that the dP across an oil filter increases as the oil gets hotter with all other factors held constant in a good lab dP vs flow setup, then we can re-write the fluid dynamics books, lol.
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I went back and rewatched the video today and found that claim to be odd. Fwiw, didn't make sense to me. It seems to go against what you have always said about the oiling system itself being ~15x more restrictive than the oil filter. Am I correct in that?
Yes, the oiling system after the oil filter is around 15 times more flow restrictive because of journal bearings and other tight flow clearances throughout the system. That's why an oil filter may only be showing 5 PSI of dP when the oil pressure going into the engine is showing 75 PSI. 75/5 = 15 times more pressure is caused by the engine vs the oil filter.
They were trying to use the engine as an "oil filter dP vs flow test rig" by simply looking at the oil pressure before and after the oil filter. Not much different than Jim Allen looking at the dP across the oil filter while driving around on the road - but his testing was much more thoural. But in this LSJr test, they really only did the test with hot oil, so it wasn't a surprise that the filter only showed around 7 PSI of dP max with hot oil. Only surprise was the statement at time 8:48 which is physically impossible as I've mentioned above. Something the YT gang will take as true and go off and spread misinformation on all the chat boards: "Hey, did you hear? LSJr says that the dP across the oil filter increases as the oil gets hotter ... so does that mean I can redline my engine right after a cold start, but I should keep the RPM way down after the oil if fully hot"
There is a good explanation for why the dP across the oil filter might increase as viscosity is reduced. The dP would decrease if the flow rate were kept constant, but the flow rate will increase as the viscosity decreases, as long as the oil pump is in pressure relief.
Oil filter dP is more sensitive to flow rate than it is to viscosity. Most of the dP from the filter canister and the filter head will be from turbulent flow, and this dP will increase with the square of the flow rate. The lower viscosity will tend to counteract this increase in dP from the increased flow rate, but viscosity on has a small effect on dP in turbulent flow conditions.
How much the oil filter dP changes with viscosity depends on how much the oil flow rate changes with viscosity, which is largely dependent on the oil pump PRV characteristics and will be different for every engine.
The additional dP that's measured with the warmer oil should be coming from the filter canister and the filter head. The dP across the actual filter media should not be increasing, since filter media should have both a very linear flow-dP curve and a very linear viscosity-dP curve. So, this increased dP that's measured is not relevant in terms of filter bypassing, but it is still relevant in terms of its effect on main gallery pressure.
Why not put these questions as comments on the YT video to see what they say?You should probably watch the video before trying to talk about the video.
Like said, what's going on after the oil filter does not effect what's going on across the filter. You could mount that filter on a test rig in a laboratory and conduct a dP vs flow test. It's done all the time per the ISO 4548 test. Look at Ascent's dP vs flow and even BR on YT dP vs flow tests. In this case, the engine was the test rig. They simply had a pressure gauge before and after the oil filter. They didn't measure oil viscosity, but simply said the oil was either cold or hot. You can see on the data screen it was around 100C when hot. "Cold" was whatever room temperature was in the dyno room .. so call it 65-70F. So if the two pressure sensors they used were located in big oil galleries before and after the filter, then for all practical purposes they were measuring the dP across the filter.
The PD oil pump like used on the GM LS will still increase volume output and therefore pressure even after the spring loaded bypass valve starts opening. In fact, that pump will start going into pressure relief well before redline, but the flow to the engine and hence the pressure will still increase at a lower rate as RPM increases.
Yes, for the overall oiling system ... but again, what's going on just across the oil can be looked at regardless of how the overall oiling system reacts to the restriction of the oiling system as a whole. They were trying to use the engine as an "oil filter dP vs flow test rig" without full instrumentation.
As covered above, the flow is not unrestricted when the pump is on an engine. The OEM LS oil pump only puts out around 7-8 GPM at redline. They didn't say what pump was on the engine (stock or aftermarket), but even an aftermarket pump like an aftermarket Melling doesn't put out much more than 10-12 GPM when on the engine depending on what pressure relief spring is used in the pump.
When they claimed the dP across the oil filter was increasing as the oil warmed up (ref time 8:48), there's no way that could physically happen unless something else was going on with the test setup that they didn't understand or didn't divulge that cold cause that to happen. When someone can prove that the dP across an oil filter increases as the oil gets hotter with all other factors held constant in a good lab dP vs flow setup, then we can re-write the fluid dynamics books, lol.
