Differences between ADBV and by-pass valve ?

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I've been wondering what are the functions of Anti Drain Back Valve and by-pass valve?
I know both of them is for preventing oil starvation of the motor but not sure how they work
 
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The ADBV essentially is a check valve that prohibits the oil from flowing out of the filter when the system is shut down. This is most generally achieved by using a nitrile or silicone formed gasket near the holes. Depending upon location of filter, and orientation of filter, on the engine, the effectiveness of the ADBV can be substantial or moderate.

The BP valve in the filter is a pressure relief valve. It's there first and foremost to protect the media of the filter from a rupture if the pressure differential (dP) across the media becomes very significant. This most often happens when the filter is first installed dry, or when the ADBV does not hold the filter full upon shut down. Additionally, the BP valve can have a secondary benefit, but one that we'd hope does not come into use. If the media were to become so loaded with particulate that it were to "blind off" (fully or partially) to a point where the flow requirement of the engine exceeded the flow ability of the filter, the BP would start to crack open and aleviate the dP, thereby saving the filter from a rupture (avoiding media bits going into the stream) as well as giving vital flow to the engine. This BP function does not happen nearly as often as many infer. Jim Allen did some data logging testing on a live engine in normal use, and found that the only time the BP opened up was at really cold starts, with an oil thicker than was spec'd for his truck, and only for a second or two until the dP balanced out. With warmed oils, or the right fluid, it didn't happen at all. How does it work? It's essentially a spring loaded relief valve. There are a few different variations in the designs used by various makers, but they all seem to work just fine. Some are on the dome end; others the base end. Different spring sizes, shapes and locations don't seem to matter in function nearly as much as they matter for fodder in a BITOG debate ... Some vehicle even have this BP feature in the engine block and it's not part of the filter, but most applications have this in the filter itself. So some filters may not list a BP value in the product data, because they don't have one.


You didn't ask, but I'll round out the last tidbit here. The oil system has a BP relief valve to protect the pump and filter. It's function is to keep the oil pressure from spiking to a point of rupturing the filter canister, and/or harming the pump as they are of positive displacement design. It will bleed off pressure to keep it at a safe level for system supply and yet still provide oil flow and pressure to the engine lube circuit. They are spec'd to the right dP and flow requirements to balance the need for relief with the need for supply.
 
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The Anti drain back valve stop the oil from siphoning back to the sump to keep the filter/pump and oil galleries primed with oil for the next engine start.

The Bypass valve on a e.g. Ryco Z30 (for a Holden/Buick) in this instance, lifts off its seat when suction Not positive pressure overcomes a preset restriction value in the filter by pass spring. Oil gets sucked through the filter with these models.

A chev Small block gets its oil filter pressurised through the oil filter media and once the bypass valve overcomes a preset restriction value in the filter housing, it springs off it seat to allow unfiltered oil flow.

The principle of the bypass valve is that any oil is better than not enough, and safety etc!

FYI: Oil will always flow from the outside of the filter media to the inside threaded hole.

To directly answer your question they are mechanical devices, you will find plenty of cut open examples on this site to look at, to imagine/see how they work.
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And welcome too!
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to BITOG!

Deleted the rest of my post as dnewton3 and ozdrrider have it covered. :]
 
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ADV - My filters are vertical so IMO the worst case is a result of hydrostatic condition if there is a small amount of U-tube effect. The filter would remain full - but destination of evacuation at point of equalization creates a second or so delay in oil to top of engine. Residual film takes care of that.
What does that mean? You will not see me at Walmart with my mouth on an oil filter.
 
What I don't understand is how the filter stays full after shut down. What keeps the oil from continuing past the media and out the outlet?
 
Against my wishes, my wife took our daughter's car to some fleabag operation for a quickie oil change.
I was totally infuriated when my daughter said she had a really hard time starting her car before a softball game later that day, feeling that my wife had just bought us a new problem at cheapo lube instead of letting me cause problems for free. After making sure there was no leak from the drain plug, I opened the hood to make sure nothing was gushing up there and noticed that the oil filter was some Brand X that I had never heard of. On a whim, I put a Mazda-branded Tokyo Roki filter that matches Subaru bypass pressure specs on the car and we haven't had any trouble with it starting since then. I got some advice on what to look for on the Brand X filter from here and verified that it didn't have an ADBV.

I don't really know why my daughter's car didn't start well that one time and I honestly have to say it's probable that it had nothing to do with the oil filter, but I also know that it didn't start well the one time it sat for several hours with an oil filter without an ADBV.
 
IMO - Hydrostatic U-tube principle ... inside geometry does not matter - height and fluid density does does - fluids on each side will seek an equilibrium and an air gap is formed on taller side. (Say you have no ADV or it leaks)
If the filter is at the low end of the U-tube (they are) - it remains full.
 
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Originally Posted By: dbeau
What I don't understand is how the filter stays full after shut down. What keeps the oil from continuing past the media and out the outlet?


Good question. Combined with the adbv, vacuum, and surface tension of the media fibers, keeps the oil from going out through the media. This is for a base down application only. That's how I have come to understand it. "People" are known to make a hole in the filter to to allow the oil to drain out through the media.
 
Originally Posted By: Virtus_Probi
Against my wishes, my wife took our daughter's car to some fleabag operation for a quickie oil change.
I was totally infuriated when my daughter said she had a really hard time starting her car before a softball game later that day, feeling that my wife had just bought us a new problem at cheapo lube instead of letting me cause problems for free. After making sure there was no leak from the drain plug, I opened the hood to make sure nothing was gushing up there and noticed that the oil filter was some Brand X that I had never heard of. On a whim, I put a Mazda-branded Tokyo Roki filter that matches Subaru bypass pressure specs on the car and we haven't had any trouble with it starting since then. I got some advice on what to look for on the Brand X filter from here and verified that it didn't have an ADBV.

I don't really know why my daughter's car didn't start well that one time and I honestly have to say it's probable that it had nothing to do with the oil filter, but I also know that it didn't start well the one time it sat for several hours with an oil filter without an ADBV.

Link to thread where you cut the filter open please.
 
Originally Posted By: Brybo86
Originally Posted By: Virtus_Probi
Against my wishes, my wife took our daughter's car to some fleabag operation for a quickie oil change.
I was totally infuriated when my daughter said she had a really hard time starting her car before a softball game later that day, feeling that my wife had just bought us a new problem at cheapo lube instead of letting me cause problems for free. After making sure there was no leak from the drain plug, I opened the hood to make sure nothing was gushing up there and noticed that the oil filter was some Brand X that I had never heard of. On a whim, I put a Mazda-branded Tokyo Roki filter that matches Subaru bypass pressure specs on the car and we haven't had any trouble with it starting since then. I got some advice on what to look for on the Brand X filter from here and verified that it didn't have an ADBV.

I don't really know why my daughter's car didn't start well that one time and I honestly have to say it's probable that it had nothing to do with the oil filter, but I also know that it didn't start well the one time it sat for several hours with an oil filter without an ADBV.

Link to thread where you cut the filter open please.


ADBV has been right by the holes and easy to see on the filters I've inspected, is there another design of which I'm not aware? Please teach me if I'm wrong. The consensus on here was it didn't have the ADBV if I couldn't see it through the holes.

No way I'm cutting a filter open, but I might have the Brand X in a bag in the garage and could google it if I can find it.
 
Originally Posted By: dbeau
What I don't understand is how the filter stays full after shut down. What keeps the oil from continuing past the media and out the outlet?
NOTHING! Oil level in filter will stabilize at some point, depending on filter's orientation to the horizontal. On my V6, Toyota uses a nipple that is three times as long as needed to keep more oil in the filter.
 
A question on the ADBV, which material is better, the nitrile or the silcone for the valve? And, how do you tell the differnce? I notice some are black and others a reddish tone?
 
Originally Posted By: RevRider
A question on the ADBV, which material is better, the nitrile or the silcone for the valve? And, how do you tell the differnce? I notice some are black and others a reddish tone?


silicone is the better material. It lasts longer.

Silicone ADBV's are usually red or terracotta color, while nitrile is black.
 
Originally Posted By: dbeau
What I don't understand is how the filter stays full after shut down. What keeps the oil from continuing past the media and out the outlet?

Surface tension. I did a test years ago to see how well the ADBV worked on a PureOne.

Drainage setup for the filter to test the ADBV.
While the filter was still pretty hot I put it base side down in a funnel and let the hot oil drain out, and then left it to drain for a whole week. After the week of draining, I then jammed some folded over Q-tip sticks in 3 of the base plate holes to open up the ADBV to let the guts drain out in a clean glass. What drained out was what the ADBV was holding back for a week.



Results of the oil trapped by the ADBV - it came out to 6 ounces.
A rough calculation of the volume between the center core and the can shell showed to be about 13.7 cu-in. Six ounces of fluid will take up 10.8 cu-in, so this means basically the ADBV was keeping the entire space between the can and center core full of oil indefinitely.
 
Originally Posted By: ZeeOSix
Originally Posted By: dbeau
What I don't understand is how the filter stays full after shut down. What keeps the oil from continuing past the media and out the outlet?
Surface tension ... basically the ADBV was keeping the entire space between the can and center core full of oil indefinitely. ...
A combination of surface tension (which keeps air from entering that space through the media), partial vacuum in that space, and the anti-drainback valve (which, if good, prevents air from entering that space through the oil-entry holes). One can drain most of the trapped oil by deflecting the ADV as you did, or puncturing the can, or repeatedly bumping the dome end of the can, which momentarily forces the ADV open to let air in.
 
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