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Sodo Mon Aug 15, 2016 5:17 pm

I have started several threads related to different aspects of transaxle oil cooling systems. This thread is focused on FILTERING. (I hope) :? :?

The idea being, that an over-engined transaxle absolutely MUST generate more steel trash in its oil. And swimming in these metal particles, wear out your 'parts' quicker, generating MORE steel trash (metal fines) in your oil. And it "compounds" like interest in the bank. More trash creates more trash.

Common wisdom is that you need the BEST oil for an over-engined transaxle. This makes sense, but if you think that since you have the best oil that it's OK to run it "dirty",,,,, that CANNOT work. :shock: ANY metal fines in the oil are hundreds, if not thousands of times bigger than the oil film thickness, therefore, if you want an over-engined trans to last, you MUST keep the oil clean. IMHO it's more important to have clean oil than to have specialty oil.

Why care about specialty EP additives (Extreme Pressure additives) when you can SEE sparkles in the oil which is visible metal-to-metal contact? If specialty oil made more than a FEW % difference in lubricity, this would reduce running temperature, and could be PROVEN by oil sellers who would trumpet this at the TOP OF THEIR LUNGS,,,,, right? Not hearing it. But more importantly and irrefutably, a little better lubricity will never overshadow the effects of oil contamination by metal fines.

So anyway, specialty oil probably makes a few percent difference but CLEAN oil is a no brainer, its not probable, its guaranteed. A tiny 5 micron steel chunk might be like an apartment building tumbling down the river, in terms of 'oil film" thicknesses. Roller bearings are not like the journal bearings in an engine. Journal bearings have larger clearances and can tolerate fine trash. Ball bearings have almost a point-contact and require clean oil. There is a reason that your engine does not have roller bearings, and if it does, they are low-load applications.

I spoke with an engineer from SWEPCO (whose focus is mainly machinery) and asked him if 12 microns was sufficient for a transmission and he said "can you filter to 5 microns?,,,the cleaner the better." So I took that as a "NO," that 12 microns is not sufficient. But it's certainly better than 140 microns (the Weddle filter). Reading machinery journals I see filtering to 3 microns. But in any case we KNOW a ball bearing is a point-contact, and that point is much less than 3 microns. I don't know how many microns are the normal surface undulations of a ball bearing and its race.

There is a VERY important ball bearing on the Vanagon transaxle, the mainshaft ball bearing. It's a KNOWN problem with big engines, it can't take the power, and overheats. I think its this bearing that has generated the vanagon transaxle wisdom of "70mph max (sustained) speed". Certainly squirting cooled oil at it will help that number though.

So anyway, for those who have oil cooling pumps on their over-engined transaxles.....ONWARD to discussion of filtering.

On my trans I used a Parker Hydraulic filter that I got on eBay for $30. It has a 12 micron element and here's a closeup of the matting where you can SEE small metallic particles that were stopped by the filter. It has a flow rating of 20gpm at 3,000 psi. I am pumping 2 gpm of 145*F 90wt thru it and it goes thru at about 16 psi. There are others available. Another pretty good one (I think) is this 7GPM unit. I have not heard of a test on this unit yet. It has a refief pressure of about 18 psi which would allow it to bypass until the oil warmed up.

I am also fooling around with a magnetic filter where you replace the 140 micron screen (Weddle filter) with a slug of neobdymium balls. Here's a pic. Pictured is $33 of spherical magnets (648 count). It looks like the Weddle filter can hold about $100 worth. There are lots of smaller aluminum FUEL filter cannisters available, I'd prefer a smaller one. This slug pictured has 648 balls, with surface area of 50 square inches. That oughtta hold a decent amount of steel particles. I'm not sure how you clean the element. Not even sure if it works. Would be a real bummer if I dropped it on the floor of my shop! :shock:



Heres a $33 magnetic filter by magnefine. I've seen them cut open (google images: "magnefine") they are not very impressive, just a paper filter and a big donut magnet (prob 2 sq. inches of surface) but a decent price. This one, Magnom Mini ($149) looks better, I think PCForno is running that unit.

Well that's enough typing, for a hot sweaty afternoon. Hope other members find this project interesting.

======== REFERENCE =======
Some of my other transaxle / cooling / oil threads. Others are working on this project too, but I can barely keep up with my own. Feel free to link other threads that members will find useful.

- Transaxle Failures every 10-20k miles ...what the heck started all this?
- the initial query into "oil cooler ports"
- Drilling for 4th gear and mainshaft ball brg oiling with some good electrical controls discussion on p5
- Drilling for the Pinion oiling
- Homebrew fittings for transaxle cooling add-on (no drilling)
- Electrical controls for Cooling system
- Periodically purifying expensive specialty gear oil (by gravity)
- Drilling transaxle port with tranny in-car (squirt 4th gear even if you have oiling plates!)

dobryan Mon Aug 15, 2016 5:38 pm

Lead on McDuff. I do love your willingness to try a lot of out of the box stuff.... :D

Sodo Mon Aug 15, 2016 9:48 pm

Thanks Dave, glad you're interested. Heres some metal-contaminated gear oil that I (miraculously!) have on hand, imagine that? It's been filtered with a 12 micron filter, but this metal dust is smaller than 12 microns, and has passed thru the filter.

First pic is where I flattened the slug of 648 magnets and dropped it into the oil, let it sit (pic2) and picked it up (pic3). It sure LOOKS like is holding onto some metal fines. I have no way to know if the magnet can hold these tiny particles against oil viscosity and movement.



Here's a pic of a paper towel, where I wiped some black oil off the ball magnets. The (other) magnet is able to lift the paper towel, indicating steel in the black oil.



Well there ya have it folks. It kinda seems like this 648 balls (= 50 sq inches magnet surface area) is a good plan. It's certainly better than the little donut magnet in the magnefine filter (prob 2 sq. inches area). But I DON'T know if it can hold onto metal fines. I do KNOW that the donut magnet in the Magnefine filter can't hold much fines. Although the donut has probably 20x the area of a VW magnetic drainplug magnet.

The plan now is to clean the 648 balls thoroughly (somehow?), and plumb my ACTUAL trans oil thru it, then LOOK & see if the balls hold onto black stuff. Then it's doing SOMETHING good, but this could take awhile....

pablum Mon Aug 15, 2016 10:10 pm

Best post since i joined. Though you had some fearsome opponents.

ALIKA T3 Tue Aug 16, 2016 2:50 am

Hi Sodo!

I like the magnetic approach, that was on the back of my head to combine that with a filter, but having somehow a plastic can with baffles or something with magnet outside for ease of cleaning.

I'm way to busy to keep working to finish up on this transmission project for now for various reasons but I love reading about your tenacity!

You didn't link the oil cooler ports thread it seems like.

Aloha!

Syncro Jael Tue Aug 16, 2016 6:25 am

Sodo,

I too have been toying with magnetic filtering. I like the ball magnets. My approach was to get a magnet inside that Weddle housing also. Currently I have the Neobdymiun rare earth magnets on the outside of the housing. When I have opened up the housing to clean the filter there is a layer of pasty looking goo where the magnets are holding very fine particles of metal. So I know this way of thinking will work.

I was going to put the magnets inside but was concerned about how they would hold up inside the oil flow. Most have a maximum working temperature of around 176°f. Neodymium Magnets are very susceptible to losing their effective magnetic field at elevated temperatures. The Neo magnet grade should be carefully selected to account for the operational temperature of the application and the magnet’s geometry. All magnet alloy will gain or lose effective magnetic field as the temperature fluctuates. Neo magnets will lose effective field as the temperature increases and are said to have a Negative Temperature Coefficient. When compared to other magnet alloy options, neo magnets lose magnetic field at a faster rate. Neo magnets effectively have a higher Temperature Coefficient (TC) when compared to other commercial alloys.

This high rate of change relative to temperature exposure results in Neo magnets being very susceptible to demagnetizing from elevated operating environments. The magnet may be exposed to a temperature which does not fully demagnetize, but reduces its’ magnetic performance to a state that it no longer is able to provide sufficient magnet field to support the application.

The loss that has been discussed thus far is considered reversible. This means that the magnet will recover the loss as it cools back down. What is typically published by suppliers of magnets is the Reversible Temperature Coefficient (RTC) for each particular grade of Neo for both the Residual Induction (Br) and the Intrinsic coercive Force (Hci). The RTC as well as the recommended Maximum Operating Temperature must be considered when selecting a Neo magnet grade for an application above ambient room temperature.

Demagnetization from Elevated Temperatures
Magnets exposed to heat can lose strength which cannot be recovered. Magnets will lose strength as they heat up, but so long as they are not taken above a certain operating point (maximum operating temperature) the strength will be recovered when they cool back down. If the magnet is taken above the operating point, a percentage of the magnet’s volume is demagnetized and the magnetic loss cannot be recovered without re-magnetizing the magnet.

The operating point is geometry specific. Most magnet providers specify a maximum operating temperature for various grades of magnet alloy, but this must be qualified. The noted upper operating temperature assumes the magnet has an appropriate geometry to tolerate the heat level of the selected alloy grade. The advertised maximum operating temperature for a particular magnet alloy grade is not always sufficient to ensure elevated temperature performance. For optimum operational heat resistance the Magnetic Length of the magnet must be sufficiently “long” relative to the area of the pole.

For instance a 0.250” OD x 0.250” Long Neo magnet, oriented and magnetized through the length, has a magnetic length to pole diameter of L/D = 1. This is a very good L/D ratio and the advertised upper operating temperature may be able to be used as the application’s maximum operating temperature. However, a magnet that is 0.250” OD x 0.125” long has an L/D = 0.5 and this would indicate that the advertised maximum temperature of the magnet must be adjusted downward or a higher heat grade selected. Typically L/D ratios over 0.7 are appropriate for the recommended operating temperatures advertised for Neo, but it is best to consult the vendor and execute thermal testing.


. They do make some high temp magnets that are rated to 300°f.

This looks like a great approach. :idea:

EDIT: Looking further into your pic, could you place the magnets in rows where the pleats are on the outside of the filter? Then slide the whole thing into the canister? If any of the magnets came loose the filter would still protect the system. Just a thought. :idea:

By the way, where are you finding those magnets so cheap? Everywhere I have looked they are about $0.30-$0.75 each, for N42 magnets.

Keep on keeping on...


Sodo Tue Aug 16, 2016 8:28 am

Syncro Jael wrote: EDIT: Looking further into your pic, could you place the magnets in rows where the pleats are on the outside of the filter? Then slide the whole thing into the canister? If any of the magnets came loose the filter would still protect the system. Just a thought. :idea:

By the way, where are you finding those magnets so cheap? Everywhere I have looked they are about $0.30-$0.75 each, for N42 magnets.

I tried to make a "fabric" of magnets and wrap it around the pleated element. Not enough space. Search eBay for "neobdymium sphere 5mm", they come from China. I bought three 30mm x 30mm x 30mm cubes = 216 x 3 = 648 Also search eBay for "aluminum filter 8AN" there are lots of little aluminum cannisters that can be filled with these ball magnets as a pre-filter to protect the pump. HOWEVER......I suspect the larger Weddle cannister is necessary to reduce the velocity of flow, to HOLD the tiny particles.

Great temperature info SJ. I had never given magnet temperature the slightest consideration. You wrote of a max temp of 176*F. My system is microprocessor temp controlled thus never gets over 150*F. I wonder if 150*F is significant. Makes sense to hold a few original magnets OUT of the oil and try to compare strength after running these awhile (up to 150*F).

One thing I've noticed is that viscosity has YUUUUGE authority in the tug-of-war with magnetic attraction (to hold onto tiny particles). I suspect that when the oil is motionless, the particle nestles onto the magnet surface, but I bet....and just guessing here....that all particles outside the (motionless) boundary layer are swept away instantly with ANY fluid motion. How thick is this boundary layer....1 particle, 2 particles? Thats not detaining a lot of "stuff". This suggests:

- increase surface area to the max possible (many magnetic poles).
- decrease fluid motion to minimum possible (large filter cannister)

And consequently, direct contact to the magnet may not be so important, for SJ's example, using magnets on the outside of the aluminum cannister. Because it's not really the quantity of attractive force, but the motionless boundary layer that allows the particle to remain. BUT you will never get more than a thin paste coating, as the outer particles get swept away each time the oil starts to flow.

Consider a "settling reservoir" in the system, where fluid near the bottom is truly motionless, this might be more effective to hold these tiny particles. A slug of neobdymuim balls in the bottom of a reservoir might be that motionless quagmire that would draw steel fines downward and hold onto them. Hence a "settling project" that doesn't require draining your gear oil. 8) 8) Just a periodic cleaning/inspection of the cup?

Steel particles being heavier than oil continue to march downward by gravity, always. Plus, steel is drawn to the magnets. This progression occurs every time the 16 oz of oil stops moving; and more completely the longer the van is parked. So you would periodically unscrew the (16 oz?) settling cup, then refill with cleaned magnets and a clean pint of oil. I guess the only way to know is to make a test unit and see if it gathers metal fines.

There's something to be said for pumping oil thru a centrifugal catchment device on one of the shafts (that would gather and HOLD fines during the transaxle lifetime like shelves on the gears do) that is cleaned at transaxle disassembly. Maybe it can fit on the mainshaft, cleanable by removing the bellhousing. Another Foolish Moment I'm sure. 8)

Is this getting crazy now? Or feasible?

I think for the moment I need to plumb this magnetic filter into my sustem downstream of the 12 micron filter and see if the magnets collect anything. But I have to drive the van some miles to do this, and my van doesn't log many miles. It could take awhile (for me).

I sure wish there were more over-engined / high-miles / tinkerers who would start testing this stuff too, I'm too slow. They're out there - Flomulgator, eJimmi, gears.....the 1.8T & big diesel crowd, there must be someone. Syncro Jael your lump is too darn sensible.....can you borrow an SVX for awhile? :roll: :roll:

Syncro Jael Tue Aug 16, 2016 10:03 am

Sodo wrote: Great info SJ. I had never given magnet temperature the slightest consideration. You wrote of a max temp of 176*F. My system is microprocessor temp controlled thus never gets over 150*F. I wonder if 150*F is significant.

This suggests:
Consider a "settling reservoir" in the system,

Sodo,

We are thinking the same. I have been contemplating a large reservoir can just for this purpose. To slow down the flow and let things have a chance to settle into the bottom with a few earth magnets. I was planning to install it on the return line after the cooling fan. This would give the system a chance to loose a few degrees before reaching the magnets.

You were saying your transaxle gear oil never gets above 150°f? On my last road trip we drove straight from northern Montana to central Utah. Around 650 miles. It was done in 95° ambient temps at 60-75mph. I ran my gear oil cooler all the time and the highest temps recorded were 167°f and that was pulling a long steep grade in 3rd gear. Most of the time it will run in the 140° to low 150° range at highway speeds. My van weighed in at 6400lbs with all of our gear on this trip. :shock: My stop to cool temp is still at 170°f. So I was close. :roll:

I am sure the maximum temps, listed from the manufacturer for the magnets, are when they are in danger of loosing their magnetism without being able to recover. I think the 300° temp magnets would be a safety margin that should be looked into. These N52 grade magnets are rather expensive, but I will attest that if I get a wrench anywhere near the ones on the Weddle filter case, it is a bugger to pull the wrench off!

From what I have been reading a magnetic filtering system is a great way to pull almost all of the metal swarf out of the gear box without adding resistance to the flow of gear oil and added pressure to the pump. A metal catch can with fins, magnets mounted to the bottom, could also help expel heat and with the added capacity, ease of cleaning, and ability to check/refresh the system with some new gear oil, it sounds like a great idea. The quick disconnects make cleaning my existing Weddle filter a snap and when I fill the filter back up, before installation, I loose only a few drops of gear oil.

One reason I installed the earth magnets on the bottom of the Weddle filter is so when the system is not pumping, gravity can also work to move the metal swarf to the magnets. The R52 magnets that I am using have a pull force of 60lbs and this magnetic field should capture a lot of particles. This layer of "swarf goo" is at the ends of the magnets inside the filter case and is like a thick paste. Once I remove the magnets, it will dissolve easily in my mason jar full of gasoline. That is how I check how much swarf the filtering system has captured.

This video shows what the Weddle Filter and the magnets recovered on an earlier maintenance check.


Sodo Tue Aug 16, 2016 10:26 am

Syncro Jael wrote: My stop to cool temp is still at 170°f. So I was close. :roll:

That's trans oil sump temp, after the cooled oil has hit the hot gears. You mentioned putting these magnets AFTER the cooler. The outlet temp of the cooler circuit has to be 20, 30*F lower than the transmission oil, right? Magnets are getting cooled oil, not 170*oil.

Interesting our temps are so different. With my system active I never saw higher than 151*F on a long hillclimb in 3rd gear, in California at about 90F+. I have my radiator at the fresh air intake to the engine bay (ala FrankenSubySyncro) and at highway speeds it almost makes no difference to turn off the fan. I see your radiator placement might be getting hot air off the highway whereas mine gets its air from the upper van corners, about 5 feet above ground. <EDIT> WALDI always reminds us that the hot air coming off the radiator exits UNDER the van.<EDIT> Could be 20 degrees difference right there (Just a wild-ass guess)

Have you measured your FINAL flowrate of the whole circuit? I wonder about quick-disconnects, if they impede the flow (do you have check-valves too?). And id you have less flow, there could be less cooling. Also what is your R&P ratio? 5:43 has more sliding in the hypoid, prob higher temps.

Sodo Tue Aug 16, 2016 1:27 pm

I took the slug of 648 magnets out of the oil and hung it overnight. Here's pics.
Some of you may appreciate the cross-pollination between Vanagon Science and other forms.



Looks like the magnets only hold onto the metal as expected.


Syncro Jael Tue Aug 16, 2016 8:13 pm

Sodo wrote:

Interesting our temps are so different.

Have you measured your FINAL flowrate of the whole circuit? I wonder about quick-disconnects, if they impede the flow (do you have check-valves too?). And id you have less flow, there could be less cooling. Also what is your R&P ratio? 5:43 has more sliding in the hypoid, prob higher temps.

No I have not checked the flow rate. But with the pump on it should look like a garden hose of gear oil.

No check valves and the quick disconnects are large so it should not impede the flow.

Stock R&P 4:86.

I am sure with the way my cooling fan/radiator is mounted there is no cool air flowing across it without the fan on. I did this purposely because we use the van so much in the dead of winter when it gets sub zero. I usually see a 20º drop when using the fan.

I can live with 150º to 160ºf transaxle temps for the high end. :D

Sodo Wed Aug 17, 2016 7:59 am

Syncro Jael wrote: No I have not checked the flow rate. But with the pump on it should look like a garden hose of gear oil.

Should....

It's not hard to check, just disconnect it (warm) at the LAST connection before it re-enters the trans and time it filling a measured container. I've been timing how fast it pumps 1/2 gallon into a clear jug, but you can time it pumping 1 quart, whatever. Then you KNOW. You have a reversible pump (the Weddle gear pump) just suck it back in.

Thats if you want to know and have the time,,,,of course. 8) Just posting this because lots of other folks are looking into cooling systems. Some PM me directly rather than post (probably because my threads have gone toxic in the past). Also because of the volume of reading it takes to distill the info. I'm always hoping for more outside ideas posted but not many are joining the threads even though it appears quite a few are designing systems "out there" and doing fantastic work too. It's a SYSTEM, it's has many facets, and can go so many directions.

Also would be great if there were some others building experience and answering questions. I understand not everyone has the time.

Anyway, ease of use, reliability, and screwing with it are all important. It's currently almost like music on a long trip,,,, I can screw with my cooler manual override and watch temps in various conditions. 8) Still in the honeymoon phase with it. :lol:

Temperature drop was the ultimate goal, and flowrate is key for that. Since then, redistribution of oil to 4th gear + mainshaft bearing, and of course filtration/purification have been important features added.

Sodo Wed Aug 17, 2016 10:17 pm

Syncro Jael wrote: could you place the magnets in rows where the pleats are on the outside of the filter? Then slide the whole thing into the canister?

You can stick them together in a rectilinear pattern.



Incidentally the 5mm balls align perfectly to the filter pleats on this Weddle filter element.



But too big to go into the cannister.



These are 5mm spheres, you can get 3mm sphere magnets. The SS screen of this element is non-magnetic, you'd have to wrap 3 mm with a screen, that would be a nice element (if it fits).

It was surprisingly EASY to clean the magnets of the fine dust. I put the gooey black mess into a jar of gasoline and shook it up and most of it washed off (AFAIK). Then I mashed it flat into a 1-ball thick fabric and laid it on the driveway and blasted it with the hose. You really have to be careful where you set this thing down, it will pick up all the metal bits it can get. I hosed off a section of concrete real clean before setting it down. Then rolling them around in a white paper towel, there's almost no black stuff left (note how clean the towel is).



The blessing & the curse.

- This magnetic 'filter element' is much easier to clean (of sub-12 micron dust) than I expected.

- A strong neobdymium (rare earth) magnet does not hold onto particles smaller than 12 microns like it holds onto bigger chunks. If just shaking it in gasoline separates the particles from the magnet, that suggests the flow must be very gentle (almost motionless) to hold fine dust. There's clearly some 'holding force' but it seems to be barely more than gravity.

Bigger chunks are easy, such as those that you see in a drainplug hairdo. The drainplug magnet most certainly lets outer particles go for a little romp around the transaxle from time to time. Perhaps recaptures them again later, perhaps not. Whereas a mechanical filter/screen will catch & hold those particles with certainty.

Pcforno Sun Aug 21, 2016 1:27 pm

Here's another datapoint. I have a recently rebuilt Syncro tranny now with 3000 miles on it, nearly all at 75 mph on the highway. I have a weddle pump, radiator, 6 micron filter followed by a "magnom" magnetic filter. The pump spray is aimed directly below 4th gear at least the MS bearing on the meshing side of the 4th gear pairing. Took a look today and found nearly zero swarf, contaminants, or otherwise. Tranny temps have averaged 150-160 over the rebuilds first 3000 miles.



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thasty07 Sun Aug 21, 2016 9:35 pm

http://www.billetconnection.com/cvf_page.html

Now that would be awesome to use. If money was no object :wink:


Sodo Mon Aug 22, 2016 12:16 am

Awesome. Great to see some other eyeballs & synapses focused on this subject. Lifetime fluid is the way to go for MFRs but for the antique vehicles crowd eternal life is more attractive.

On another note the spherical filter media project is losing its luster. Held some talks with the think tank at Mogfest and intend to do a little more testing to clarify soon. Just wanted to get this posted before anyone orders $33 of magnets. Pretty sure theres a better way.

Basically the magnets in contact with each other diminishes their ability to hold onto metal fines. Which is kinda good for "cleaning" but not so great for "filtering".

thasty07 Mon Aug 22, 2016 6:31 am

Here is another thing to consider or look more into, I called Derale who make alot of transmission coolers and filters and asked what their lowest micron level filter was, hoping to get into the 10-12 range. Their lowest was 21 microns, and the tech said they wont go any lower because after that you run the risk of actually stripping the oil of its properties if it gets over filtered.

Im gunna call a couple other places to see what they say but it sounds like there could be a bottom end to filtering.

ejimmi Mon Aug 22, 2016 9:17 am

thasty07 wrote: Here is another thing to consider or look more into, I called Derale who make alot of transmission coolers and filters and asked what their lowest micron level filter was, hoping to get into the 10-12 range. Their lowest was 21 microns, and the tech said they wont go any lower because after that you run the risk of actually stripping the oil of its properties if it gets over filtered.

Im gunna call a couple other places to see what they say but it sounds like there could be a bottom end to filtering.

This is interesting, I have wondered the same thing after seeing this micron specification chart.

50 microns – Diameter of a human hair
40 microns – Lower limit of visibility of a human eye
25 microns – White blood cells
8 microns – Red blood cells
2 microns – Bacteria

There must be a limit? And Sodo is just the guy to find it :D

I went with a 100 micron pre pump filter and a 40 micron Post pump filter with a mix of magnets In various areas.

After rebuilding my box, I setup up my pump/filter system @ 1300 miles and the oil drain plug had less Swarf on the magnet than it did @ 100 miles. Since I'm creating less swarf with the box broke in, I'm pretty comfotable with my filter choices.

There should be a further reduction in swarf/fines if the cooled oil is keeping the bearing surfaces cooler. If less swarf is being created less filtering should be needed. This should extend the "sweet spot" of the transaxles life. Once the bearing surfaces wear down and start to create excess swarf again it will be time for another rebuild, rather than a smaller micron filter.

Sodo Mon Aug 22, 2016 9:43 am

ejimmi wrote: There should be a further reduction in swarf/fines if the cooled oil is keeping the bearing surfaces cooler. If less swarf is being created less filtering should be needed.

Goes around, comes around. There will be a point of diminishing returns, and any filtration had to be better than no filtration. If a particle is 'generated" and detained by a filter quickly, that's about a million times better that waiting a year or three.

With regards to the "minimum", try calling some oil mfrs. I called Lubrication Engineers and they said their additives cannot be filtered out, and a Swepco engineer said pretty much any oil can be filtered to 1 micron without disturbing the additives. What you (or some crazy member) hear on the phone then repeat in a forum is not gospel but it can perhaps lead to something useful, so please report whatever you hear.

Interesting what Derale said. Keep in mind that if Derale told you that finer filtration is BETTER than their finest filter offering can do, they just lost a customer. In the same way, if an oil MFR tells you their additives can be filtered out at 20 microns (not knowing that you have been filtering to 3 microns) they too can lose a customer. Hard to know what's going on when there's marketing facts mixed in with physical realities.

Someplace else (perhaps "Lubrication Journal") I read that additives that bind to contaminants will get filtered out, and thus deplete in that way. For example EP additives binding to a particle of metal contamination will then be caught in the filter with that particle. Additives that clump together in the presence of water get filtered out. But wasn't that additive component already 'depleted'? It was running with the wrong crowd, relegated to protecting your other parts by encapsulating a dangerous contaminant. Better, I think to go ahead an remove the contaminant, rather than worry about an additive that can no longer contribute anyway.

Also useful is this except from a paper on 'geartechnology.com' where they recommend filtration to 3 microns.


bluebus86 Mon Aug 22, 2016 9:51 am

Sodo wrote: ejimmi wrote: There should be a further reduction in swarf/fines if the cooled oil is keeping the bearing surfaces cooler. If less swarf is being created less filtering should be needed.

Goes around, comes around. There will be a point of diminishing returns, and any filtration had to be better than no filtration. If a particle is 'generated" and detained by a filter quickly, that's about a million times better that waiting a year or three.

With regards to the "minimum", try calling some oil mfrs. I called Lubrication Engineers and they said their additives cannot be filtered out, and a Swepco engineer said pretty much any oil can be filtered to 1 micron without disturbing the additives. What you (or some crazy member) hear on the phone then repeat in a forum is not gospel but it can perhaps lead to something useful.

Interesting what Derale said. Keep in mind that if Derale told you that finer filtration is BETTER than their finest filter offering can do, they just lost a customer. In the same way, if an oil MFR tells you their additives can be filtered out at 20 microns (not knowing that you have been filtering to 3 microns) they too can lose a customer. Hard to know what's going on when there's marketing facts mixed in with physical realities.

Someplace else (perhaps "Lubrication Journal") I read that additives that bind to contaminants will get filtered out, and thus deplete in that way. For example EP additives binding to a particle of metal contamination will then be caught in the filter with that particle. Additives that clump together in the presence of water get filtered out. But wasn't that additive component already 'depleted'? It was running with the wrong crowd, relegated to protecting your other parts by encapsulating a dangerous contaminant. Better, I think to go ahead an remove the contaminant, rather than worry about an additive that can no longer contribute anyway.

Also useful is this except from a paper on 'geartechnology.com' where they recommend filtration to 3 microns.






note filters, magnets, settling of oil will not un-oxidize oxidized oil. if you run a lot of load in the tranny the oil will get hotter, and oxidation rate will increase, there is a limit as too what a cooler can do. consider oil as comsumable, dont try to give it an infinate life with filtration, settling, magnets, eventually it might fail you by oxidation.

good luck



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