Originally Posted By: Hokiefyd
It makes a difference in Chrysler's V-6 engines anyway. Some engines may not be as sensitive to it, sure. The phenomenon may exist in some engines and not others.
That's certainly possible. My experiences are mainly with Chevrolet small blocks and various Ford engines. For just about every Ford I've had, because of the filter orientation, an ADBV was useful.
Originally Posted By: Hokiefyd
I agree and disagree. With the head pressure above the filter, and with no or a malfunctioning ADBV, oil can push back through and into the pan. The filter may still be full, but there may be no oil above it. It's apparent that something in your Audi's lubrication system is different from that of other engines, and the oil is retained up in the engine without the use of an ADBV in the filter itself. But I've experienced different in other types of engines. In some engines, even with a vertical filter, a good ADBV is a prerequisite for quiet starts.
I don't doubt that oil would backflow in such a scenario. Whether or not it's an issue is another matter. When a filter that holds close to a quart is sitting sideways or upside down and dumps its contents due to gravity, I'd suggest that would be a more important reason to have an ADBV. The filter capacity (at least for "normal" sized filters) for oil is a lot higher than what would be retained in passages above it.
I honestly don't know what it is about my Audi. Regardless of the filter used, a fair bit comes out from above it when it's loosened. I have seen that on Chevy small blocks, but not quite to the same degree. And I still have no idea as to why Wix has the ADBV for its filter, whereas Mann, Mahle, and Bosch do not. Others have pointed out to me that Wix doesn't put an ADBV in absolutely every filter they make. My original thought was that, perhaps, they simply did it in all their filters as a matter of course.
Perhaps the Audi has some strange oil circuit geometry. As I mentioned, it's nowhere near the lowest point in the oil circuit. One would think that in such an arrangement, it would be possible for the oil above the filter to siphon backwards; of course the filter would remain full. Obviously, it's not siphoning backwards for some reason.
With the Chevy small blocks, there certainly was oil above the filter, albeit not as much as with the Audi, at least if one compares the respective filter sizes. If I recall correctly, the Chev filters were mounted relatively lower in the oil circuit than on the Audi.
Originally Posted By: goodtimes
It has been awhile since I had my 71 Chev small block, but I do believe the bypass valve, which is removable and right under the filter, as far as I remember, MAY also have been the adbv in some models.
The bypass and ADBV are not the same thing. I have heard of the conversion that is possible for the bypass. However, it's simply not the same thing. On a related note, in years past, part of the marketing for filter relocation kits made note of how these kits made it possible to orient the filter vertically, to preclude the necessity of an ADBV when they were less common in filter construction.
It makes a difference in Chrysler's V-6 engines anyway. Some engines may not be as sensitive to it, sure. The phenomenon may exist in some engines and not others.
That's certainly possible. My experiences are mainly with Chevrolet small blocks and various Ford engines. For just about every Ford I've had, because of the filter orientation, an ADBV was useful.
Originally Posted By: Hokiefyd
I agree and disagree. With the head pressure above the filter, and with no or a malfunctioning ADBV, oil can push back through and into the pan. The filter may still be full, but there may be no oil above it. It's apparent that something in your Audi's lubrication system is different from that of other engines, and the oil is retained up in the engine without the use of an ADBV in the filter itself. But I've experienced different in other types of engines. In some engines, even with a vertical filter, a good ADBV is a prerequisite for quiet starts.
I don't doubt that oil would backflow in such a scenario. Whether or not it's an issue is another matter. When a filter that holds close to a quart is sitting sideways or upside down and dumps its contents due to gravity, I'd suggest that would be a more important reason to have an ADBV. The filter capacity (at least for "normal" sized filters) for oil is a lot higher than what would be retained in passages above it.
I honestly don't know what it is about my Audi. Regardless of the filter used, a fair bit comes out from above it when it's loosened. I have seen that on Chevy small blocks, but not quite to the same degree. And I still have no idea as to why Wix has the ADBV for its filter, whereas Mann, Mahle, and Bosch do not. Others have pointed out to me that Wix doesn't put an ADBV in absolutely every filter they make. My original thought was that, perhaps, they simply did it in all their filters as a matter of course.
Perhaps the Audi has some strange oil circuit geometry. As I mentioned, it's nowhere near the lowest point in the oil circuit. One would think that in such an arrangement, it would be possible for the oil above the filter to siphon backwards; of course the filter would remain full. Obviously, it's not siphoning backwards for some reason.
With the Chevy small blocks, there certainly was oil above the filter, albeit not as much as with the Audi, at least if one compares the respective filter sizes. If I recall correctly, the Chev filters were mounted relatively lower in the oil circuit than on the Audi.
Originally Posted By: goodtimes
It has been awhile since I had my 71 Chev small block, but I do believe the bypass valve, which is removable and right under the filter, as far as I remember, MAY also have been the adbv in some models.
The bypass and ADBV are not the same thing. I have heard of the conversion that is possible for the bypass. However, it's simply not the same thing. On a related note, in years past, part of the marketing for filter relocation kits made note of how these kits made it possible to orient the filter vertically, to preclude the necessity of an ADBV when they were less common in filter construction.
