when to change the full flow filter?

[The motor guy]

I was thinking of getting a bypass filtration system. Probably the amsoil one. Or any other spin filter type. Amsoil is the only one I know of. But how often do you change out the full flow filter? I was thinking you just change it at the same time you would the bypass filter since the bypass filter should keep the oil clean enough that the full flow would never clogg and go into bypass mode. Does this sound like good thinking?

 

[chubbs1]

I think the directions will probably tell you. Call AMSOIL up and they will get you on the right track.

 

[Steve S]

when I serviced semis at work the fullflow and the bypass were changede at the same time. All the oil goes through the full flow and a small percentage goes through the bypass in comparison. Why the bypass filter setup ? to extend the oil change interval?

 

[dnewton3]

Actually, the two filters (obviously) do different things, and therefore may not have the same service life.

I don't know for sure, and I'm sure Amsoil has a recommendation, so I'd follow that.

Fundementally, the FF filter catches all the big "chunks". Typically, and in reality, these really don't happen that often. If they did, then all us "normal, non-bypass" folks would have engines sieze in 10k miles. So while the severity of large particles is significant, the frequency of their occurence is very, very low.

The bypass filter, OTOH, catches all the small stuff. It strips out the small particles that the oil's add-pack is holding. Basically, the oil is the carrier of "small junk"; the anti-agglomerate (dispersent) additives hold small particles in suspension. There are two ways to get rid of that contamination; either filter it out with bypass, or flush it out with an OCI. Either way works.

Generally, it's reasonable to think that particles 10um or larger are caught with good frequency the first time through the full flow filter, and anything 20um or bigger are almost assured to be caught the first time around. Particles 3um or larger are caught with almost certainty the first time into a bypass filter.

Another thing to remember is that the typical bypass filter system (regardless of brand) only runs about 5-10% of the total volume flow. They are designed this way on purpose. To be so efficient in catching small stuff, both the flow rate and flow volume have to be low enough for the tight media to work. This very slow/low fluid flow cannot support the engine's demand for oil, so the oil is restricted from going into the bypass filter on a ratio of around 10:1. The engine needs most of the flow and volume for the hydrodynamic wedge to float the parts on; if you send it all into the bypass, it will starve the engine for oil. I suppose one could buy 10 bypass filters, plumb them all in parallel, and get the volume needed, but that would be cost prohibitive. (Although, I would not put it past some BITOGGER to try it ...)

So with a typical bypass filtration system, if there is a particle with potential for damaging the engine, it only has a 10% chance of being caught by the bypass filter because it has a 90% chance of simply never going to that filter in the first place. Now, let me make a clear distinction. I am not saying that the bypass filter is only 10% efficient; I'm saying that it only has a 10% chance of catching particles because it only sees 10% of the TOTAL volume flow. Imagine a "T" intersection: 90% of the cars turn right onto the highway; 10% of the cars go left to the amusement park. The total exposure of the traffic flow introduces 10% to the park, and the rest of the cars are not able to be processed. Get it? So, a bypass filter is very efficient at removing stuff, but it only gets a maximum of 10% opportunity to do as such. Therefore, by simple exclusionary math, any particle 2um to 10um in size has a very high probability of "bypassing the bypass filter" (going instead straight for the full flow filter) and heading right into circulation.

* Particles that are large enough to be caught with high probability in the full flow filter are typically caught the first or second time around. Either filter will catch them.
* Particles too small for the full flow filter to catch are still carried around by the oil. These particles have a 90% chance of running amok in the lube system before they are ever intoduced to the bypass filter; 9 out of 10 times they are picked up by the pump, they will go right into the engine.
* The oil add-pack is the primary means of controlling contamination. Until that add-pack is overwhelmed (depleted), the filters are only along for the ride.

So, to the OPs question, the rate of filter loading is not likely the same for each filter. It is likely wrong to assume that the bypass filter will keep the full flow filter from loading up; they act independently. Each brand of bypass system manufacturer likely has FCI recommendations based upon their own studies and design, and I'd follow those.

Food for thought.

 

[slalom44]

I'm using the Amsoil Dual Remote Bypass system, and I change my full flow filter and bypass filter at the same time. I'm currently doing 35,000 mile OCIs, and planning to go to 40,000 miles with my next OCI. My used oil analysis show that it's working great.

 

[The motor guy]

Originally Posted By: slalom44
I'm using the Amsoil Dual Remote Bypass system, and I change my full flow filter and bypass filter at the same time. I'm currently doing 35,000 mile OCIs, and planning to go to 40,000 miles with my next OCI. My used oil analysis show that it's working great.

Do you happen to keep track of the hours also along with miles? What vehicle is this system on?

 

[The motor guy]

I was hoping to start doing oil and filter changes at 1000-1200 hour intervals or 20-25,000 miles. I know one person he also does 40,000 mile oil changes with the amsoil system and changes everything out at that time. He does hot shotting and his truck runs for 11 hours per day and idles 10 hours at night. His oil samples say he can go farther but he just changes it at that time so he doesn't push his luck. Got over 300,000 miles doing this and still going strong.

 

[The motor guy]

Well my theory is that the bypass filter even though it filters to two microns the entire sump would prabably stay around the 5-7 micron range. Cause by the time the particles work their way up from 2 microns to around 7 microns it would probably pass through the bypass filter again. So staying around 5-7 microns would in theory never be large enough to plug the full flow filter. So with the bypass filter only filtering 10 percent it still should be able to keep the particles well below the size that causes the most engine wear which would be like 8 microns and larger. If it can't keep the oil in the pan between 5-7 microns then I don't see the benefit of even using a bypass filter other than extended oil drains. You could get the same engine life by doing regular 5000 mile oil changes. But dnewton I see your point of how people think that because the system filters down to two microns they think the entire oil pan contains 2 micron filtered oil when that isn't the case. Ive seen quite a few uoa showing bypass oil filtration keeps the oil below the level that causes the most wear.

 

[slalom44]

Originally Posted By: motor_oil_madman
Do you happen to keep track of the hours also along with miles? What vehicle is this system on?

I have this system on an '03 Honda S2000. Here's my last UOA with info on my setup.

No, I didn't keep track of hours. I've never known anyone that monitors hours on their car.

 

[slalom44]

Originally Posted By: motor_oil_madman
Well my theory is that the bypass filter even though it filters to two microns the entire sump would prabably stay around the 5-7 micron range. Cause by the time the particles work their way up from 2 microns to around 7 microns it would probably pass through the bypass filter again......

I don't understand your logic. If (for example) 10% of the oil passes through the bypass filter (which is common) and your oil pump pumps at an average rate of 3gpm (which is conservative), then the probability is that 96% of the oil will pass through the bypass filter at least once every 30 minutes. You would have to introduce a great deal of dirt into the oil system to maintain any amount of particles inthe 5-7 micron range.

 

[The motor guy]

My logic is that when the bypass filter is not filtering the oil the particles in the oil are slowly increasing in size when it goes through the engine and continues to increase until it goes back to the bypass filter again. I can assure that just because it has a bypass filter that goes down to 2 microns does not mean that the entire sump is full of 2 micron oil. This is because not all the oil goes to the bypass filter at once. Now if the oil went straight from the bypass filter to the engine that would be different.

 

[The motor guy]

Do you think I should switch over to the EAO80 oil filter for my truck when I do the amsoil bypass? Or just keep using the fleetguard stratapore? I think the stratapore is suppose to be less restrictive compared to the EAO80 oil filter. The EAO80 amsoil filter filters at 15 microns while the fleetguard does 25 microns. I don't think the particles would ever get larger than 15 microns. I would prefer to use the fleetguard as the full flow filter instead of both full flow and bypass being amsoil because its like 10 bucks cheaper and better flow. What do you guys think?

 

[TiredTrucker]

Originally Posted By: motor_oil_madman
I was hoping to start doing oil and filter changes at 1000-1200 hour intervals or 20-25,000 miles. I know one person he also does 40,000 mile oil changes with the amsoil system and changes everything out at that time. He does hot shotting and his truck runs for 11 hours per day and idles 10 hours at night. His oil samples say he can go farther but he just changes it at that time so he doesn't push his luck. Got over 300,000 miles doing this and still going strong.


Wow! I run 11-12 hours a day with my semi, but I sure wouldn't let it idle for 10 hours straight. What would be the need? There are only a certain number of days in a year that would require idling such as extremely hot or cold temps so one could get some rest. My truck runs thru almost a gallon of fuel per hour idling. That equates to several thousands of dollars per year in wasted revenue. But what they hey... it is only money. I like to keep as much of mine as I can.

 

[Gary Allan]

Originally Posted By: motor_oil_madman
My logic is that when the bypass filter is not filtering the oil the particles in the oil are slowly increasing in size when it goes through the engine and continues to increase until it goes back to the bypass filter again. I can assure that just because it has a bypass filter that goes down to 2 microns does not mean that the entire sump is full of 2 micron oil. This is because not all the oil goes to the bypass filter at once. Now if the oil went straight from the bypass filter to the engine that would be different.


It ends up being an issue of "particle management". You're correct that it's not going to create a 2um sump. You're producing particles of various sizes all the time. It would be different if it was a more static sump ..like say a transmission. There you can get the fluid very clean after xx cycles through the bypass. The capture to production ratio makes it a bringing a gun to a knife fight scenario.

Originally Posted By: motor_oil_madman
Do you think I should switch over to the EAO80 oil filter for my truck when I do the amsoil bypass? Or just keep using the fleetguard stratapore? I think the stratapore is suppose to be less restrictive compared to the EAO80 oil filter. The EAO80 amsoil filter filters at 15 microns while the fleetguard does 25 microns. I don't think the particles would ever get larger than 15 microns. I would prefer to use the fleetguard as the full flow filter instead of both full flow and bypass being amsoil because its like 10 bucks cheaper and better flow. What do you guys think?


How do you know ..or rather why do you think it has better flow? Are you slammed up against your oil pump's pressure relief? If not ..then there's no flow to be diverted anywhere. Naturally, as the filter saturates, there CAN be more PSID across the media ..but there's no way of telling if that elevated PSID is enough to open the bypass. You need to contact FG and ask for the holding capacity of the filter.

They both live their life on a curve. The numbers you see aren't what they deliver out of the box. The closer to the holding capacity limit, the "smaller" the filter appears to flow from a viscosity standpoint. It retreats as the oil warms. It would take near full saturation to make the filter appear that small to be in bypass all the time.

 

[The motor guy]

My point was I don't think the sump will ever exceed 15 microns. Both the amsoil EAO80 and the fleetguard LF16035 use synthetic media. So I don't think there is any point in spending the extra money for the amsoil filter to be in the fullflow location. I had heard on other forums that the amsoil is more restrictive than the fleetguard because it sacrifices flow for filtration. But I don't have any numbers or anything like that on how much is restricts the flow. Just what i have heard. And you know how that goes. Might have correct info might not. lol. Now if I find out that the amsoil can hold much much more and go alot longer then I might consider the amsoil filter over the fleetguard.

 

[The motor guy]

I doubt he leaves it running if the weather is nice.

 

[slalom44]

Originally Posted By: motor_oil_madman
.... I had heard on other forums that the amsoil is more restrictive than the fleetguard because it sacrifices flow for filtration. But I don't have any numbers or anything like that on how much is restricts the flow. Just what i have heard. And you know how that goes. Might have correct info might not. lol. Now if I find out that the amsoil can hold much much more and go alot longer then I might consider the amsoil filter over the fleetguard.
If you read it on the internet it has to be true.

I've never seen any flow comparisons, but I've read plenty of conjecture to support someone's favorite brand.

I have used a filter (Trasko) numerous times on 10,000 mile OCIs that uses a fine wire mesh for its full-flow filter media. I can tell you that there is practically nothing in that mesh when I clean it out. I have dissected countless filters of various brands and besides being dark and oily, you can't tell if it trapped anything, let alone become fully loaded. I went 35,000 miles on my last OCI and filter (along with a bypass filter) and that media was no different.

I personally believe that there is almost no difference in the pressure drop and flow through a filter over the typical OCI unless the engine has a problem. I also believe that virtually all full-flow filters go into bypass with cold oil at startups - I used two oversized filters years ago with failed media due to bad bypass valves to prove it. If (allegedly) restricted media caused a problem, you'd see evidence of it in the thousands of used oil analysis posted here, and you just don't see it.

If you really want to minimize your filter going into bypass, use a 0W- oil.

 

[slalom44]

Originally Posted By: motor_oil_madman
My logic is that when the bypass filter is not filtering the oil the particles in the oil are slowly increasing in size when it goes through the engine and continues to increase until it goes back to the bypass filter again. I can assure that just because it has a bypass filter that goes down to 2 microns does not mean that the entire sump is full of 2 micron oil. This is because not all the oil goes to the bypass filter at once. Now if the oil went straight from the bypass filter to the engine that would be different.
No offense, but I don't buy your logic. Particles don't grow in size. Cumulatively, it's unlikely that the average particle size will increase either since the bypass filter is continuously taking a percentage of your oil and filtering it just like your kidneys do with your blood, and we don't go into renal failure unless we have another problem. If anything, the bypass filter is becoming more efficient as the larger pores get plugged.

And if average particle size did increase, you would see evidence of this in used oil analysis. Here are the used oil analysis for my vehicle. As you can see the amount of silicon per mile doesn't increase with increased miles.

It seems that you are assuming that your engine would be ingesting particulates at a faster rate than the bypass filter removes them. At 35,000 miles my bypass filter still has flow (i.e. - is not plugged up with trapped particles).

 

[Gary Allan]

Quote:
I had heard on other forums that the amsoil is more restrictive than the fleetguard because it sacrifices flow for filtration


When you hear this ..ask whomever says it to explain how they know this to be true. They don't. Even with bench figures to compare, the way a filter appears with the backpressure of the engine has little resemblance to one sitting on a bench with a swatch of media and an applied pressure. It doesn't work that way.

Quote:
My point was I don't think the sump will ever exceed 15 microns.


I'm sure it will. It's the amount of above xx micron particles that will be limited.

A filter rated at 15um Absolute doesn't filter to 15um out of the box. That's not how the multipass protocol reads. The hydraulic protocol works that way, irrc.

The read above and below the filter with an optical laser doing the particle counting. There's some flow spec and some time spec where they put material in the upstream part. Anyway (this is from memory, so don't hold me to the exact description) ..when it's "shot" ..the last best reading is the rating. The swatch is weighed ..and that determines your holding capacity AT THE RATED EFFICIENCY LEVEL.

..which is when you should be throwing it away.

 

[Doug Hillary]

Hi,
I used a centrifuge cleaner on my 60 Series Detroits. Initially I changed the FF filters at 50% of the OCI. On opening they were virtually clean. Our main concern was going twice the OEMs recommended filter life statement. The concern was media deterioration - we never saw any!

After changing to Synteq Donaldson FF filters these were changed at the OC and the centrifuge was cleaned at the same time. The FF filters were opened and never had debris or "sludge". The centrifuge was around 1/3 full (it holds 600g)

Next, and after monitoring holding capacities and the condition of the Synteq FF filters (for weeping seals etc), we dispensed with them altogether in favour of 35micron Stainless Steel FF cartidges and cleaned these along with the centrifuge at every second OC

This process was in place on my small Fleet for about a decade

Average OCI was 90kkms - longest 130kkms!