Discussion about ADBV on a vertical oil filter

[river_rat]

FWIW my truck sat unstarted for about 48 hours before today's OC.
I decided to do a cold drain anyway since the old oil hasn't been in many miles...just changing it before fall.
I punched a hole in the filter dome and let it drain.
The filter had to have been completely full, and then maybe some column, for the amount that came out.

 

[Gary Allan]

Originally Posted By: 09rexwagon
Ok, so let me see if I make a somewhat concise statement that most (if not all) of you can agree on:


"With a vertical oil filter on an engine that is relatively low on the vehicle with respect to the sump, an anti drainback valve is somewhat non effectual from the standpoint of maintaining full oil passages in the engine while the engine is not running. After (let's say) 5 hours, it is likely that oil will drain back through the filter, through the pump and back into the sump (leaving only the filter full of oil. However, a quality ADBV would be beneficial from the standpoint of allowing the dirty oil to flow past the rubber/nitrile/silicone valve into the dirty 'side' of the filter with minimal impedance, even when the ADBV is cold."

That sound about right?


This part I can't get where you're coming from:

Quote:
However, a quality ADBV would be beneficial from the standpoint of allowing the dirty oil to flow past the rubber/nitrile/silicone valve into the dirty 'side' of the filter with minimal impedance, even when the ADBV is cold."


The way you're wording it makes it appear that the valve is on the outlet of the filter. The valve is the first thing the oil flow sees when the engine is running. It's a check valve on the inlet. There are some Oz filters that have one on either end.

All ADBV's meet or exceed OEM spec's. They're required to hold for so long after being "reverse biased".

That "dirty side/clean side" thing came from the original knizefamily filter study. He whined excessively about "allowing dirty oil to drain back to the sump" ...which is EXACTLY where it came from in EXACTLY the condition it was in. Oil doesn't look too much different one pass from another. For some reason his repeated obsession on it ..well, it annoyed me

He's updated the site since the original ..but he managed to say it on the Fram filter

In practice these seem to leak, causing dirty oil to drain back into the pan.

Why would anyone care about dirty oil draining back to the pan that it came from?

This ONE element causes me to question his reasoning to the extent that, while he can surely observe (sorta) and conclude, he may be objecting (or sounding like he is) to "nothing".

Do you know that man actually sleeps with HIS WIFE??? The nerve!!

 

[09rexwagon]

Quote:


The way you're wording it makes it appear that the valve is on the outlet of the filter. The valve is the first thing the oil flow sees when the engine is running. It's a check valve on the inlet. There are some Oz filters that have one on either end.

All ADBV's meet or exceed OEM spec's. They're required to hold for so long after being "reverse biased".

That "dirty side/clean side" thing came from the original knizefamily filter study. He whined excessively about "allowing dirty oil to drain back to the sump" ...which is EXACTLY where it came from in EXACTLY the condition it was in. Oil doesn't look too much different one pass from another. For some reason his repeated obsession on it ..well, it annoyed me

He's updated the site since the original ..but he managed to say it on the Fram filter

In practice these seem to leak, causing dirty oil to drain back into the pan.

Why would anyone care about dirty oil draining back to the pan that it came from?

This ONE element causes me to question his reasoning to the extent that, while he can surely observe (sorta) and conclude, he may be objecting (or sounding like he is) to "nothing".

Do you know that man actually sleeps with HIS WIFE??? The nerve!!

Yes Gary, the wording is off. I meant the ADBV can cause an impedance of the oil flow going through the circumferential dirty side holes since it has to 'push' the ADBV back and flow around it while the engine is on and the oil is flowing in the traditional direction.


But I agree, the point of the ADBV should not be to prevent dirty oil from draining back into the sump since that's where the dirty oil is stored...it SHOULD be to keep all of the oil passages that are at an elevation that is greater than the elevation of the ADBV full of oil...end of discussion. The real question then because, how effective is it at doing that job?

 

[Gary Allan]

An ADBV valve "may" do that. That is not its intended purpose. Some engine manufacturers have used that feature to their advantage in terms of reducing startup noise.

That is, that's not it's intended goal ..but some have adopted/adapted it to their advantage. Its purpose is to slow and/or delay the back flow process. That's it. The keeping the oil passages full deal is sorta like fleas on the dog. They're an attached rider to a policy that was well inforce long before they were fleas.

If Ford REALLY cared about startup noise beyond customer complaints, wouldn't you think that there would be some prohibition on nitrile ADBV's??? Have you ever seen such a prohibition stated anywhere?

Edit: Now I see where you were coming from on the rigidity of hte ADBV when cold. Neither are hard to flex when cold. The silicon valve is just far more conforming and pliable. It's not like either are hard to flex the few mm's (if that) when cold at startup.

That is, no one worries about an ADBV in the forward bias position. It's only the reverse bias characteristic of oil retention that we are obsessed with.

 

[labman]

Ford likely doesn't forbid nitriles because the silicones' advantage is marginal at best. I think some of the discussion in this thread has shown that in most cases, the ADBV is indeed doing it job.

 

[SuperBusa]

Originally Posted By: river_rat

It is impossible to seal perfectly with a normal filter mount even if the ADBV is perfect. Oil can still slowly seep out between the threads of the center nipple and bypass the filter while seeping back to the pan. There is no O-ring or anything on that filter to nipple non-tapered thread. It will always seep backwards.


I'd say that's stretching it a bit. With the filter tight, there is enough sealing on the center threads to keep oil from leaking past the threads ... especially when the car is off and no real driving pressure is present.

If the center mount hole threads always leaked like you theorize, then when the engine is running there would be some dirty oil bypassing the filter all together due to the thread leakage. I don't think there really is any to speak of.

 

[SuperBusa]

Originally Posted By: labman

I have found used filters hold on to their oil for dear life. I have left filters upside down for a week or more and not had the oil drain out. Even in my foolish youth when I was using Frams. Better shops crush oil filters to remove the oil before disposing. No crusher, but I have a drill, and use it to make a drain hole in the dome end.


Yes, a filter will never drain completely due to just the gravity forces on the oil, as the filter element kind of acts like a "sponge" and will always retain some oil. The surface tension of the oil will cause it to cling to some extent.

One could always do the following experiment on a removed oil filter the next time you do a change. a) With filter base side up, fill the filter with oil and let it completely "soak in" ... keep filling with oil until it won't take any more oil. b) Turn the filter with the base side down, and let it drain in a clean container for X hrs, X days, X whatever. After X time has gone by, measure how much oil volume has drained out. c) Cut open filter and let the remaining oil drain out. d) Measure remaining oil volume and add to volume measured in b). Compare total volume the filter can hold to volume of oil drained. This would give you an idea of how fast a filter will drain in the worse case scenario.

 

[SuperBusa]

Originally Posted By: labman
Sometimes I am a slow thinker. If the ABDV let the oil above the filter run out, it should let the oil above the lowest inlet hole out too. So if you let it set the mentioned 5 hours, you should be able to remove the sideways or thread down filters without oil going everywhere. Maybe in the interest of science, I will try that next oil change. After all, I think my truck has pockets that trap about 2 quarts when I drain it. How much harm can letting filter cool before removing it do?


I've done this on two vehicles with completely vertical, base down filters. RX-7s, and Tacoma 4.0L V6. I would drain the oil hot and let it drain overnight. The next day I'd pull the filter and continue the oil change. When the filter was removed 12 ~ 16 hrs later, it would puke oil all over the place ... it was by no means drained empty because the ADBV let it.

By all means, try this way of changing your oil and filter next time, and you'll probably see there is going to be an oil mess just like if you pulled the filter 10 min after shutdown.

 

[river_rat]

Originally Posted By: SuperBusa
I'd say that's stretching it a bit.

I have to stick by what I said. But I'm not talking about draining out through there overnight or even a week. I really meant eventually...like in long storage. :2cents: