Thread split from original thread SuperTech Oil Filters by forum Moderator
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Quote:
Originally posted by gtm245 The anti-drainback valve doesn't really matter to me because my oil filter hangs vertically. I'm still wondering about the whole efficiency that I first posted. Can anyone elaberate on this?
Be careful about that, in some cases, the oil can siphon back out of the filter, so the anti-drainback valve is important IN ALL applications.....
Last edited by horsepuller; 02-03-2004 at 12:08 PM.
Originally posted by oppy How is that possible Bob?
There is a return path back to the oil pan through the oil pump. If
there wasn't, then an anti-drainback valve wouldn't be needed, regardless how the filter was mounted...When the oil flows back into the pan, it will siphon it out of the filter.....
I respectfully disagree, Bob. There's no way oil's going to siphon it's way through that gear pump. The reason the bypass valve is in the filter is because it works in several applications. Otherwise, 2 different filters would have to be stocked (which is actually the case in Chebby V-8 applications).
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Originally posted by oppy I respectfully disagree, Bob. There's no way oil's going to siphon it's way through that gear pump. The reason the bypass valve is in the filter is because it works in several applications. Otherwise, 2 different filters would have to be stocked (which is actually the case in Chebby V-8 applications).
Oppy, we are talking anti-drainback valves, not bypass valves....
Think about it, if the oil could not flow back through the oil pump, why doesn't the oil pump act like an anti-drainback valve, and one would not be needed in the filter....
I've never thought about it before, but what Bob says makes sense. The oil pump doesn't have any type of check valve on either end of it. So when you switch the engine off the oil pump is packed full of oil. Then as the oil begins to drain back to the pan out through the suction of the pump, it forms a syphon. It would suck the oil out of the filter too, if not for an anti-drainback valve in the filter.
It also makes sense that the auto manufacturers put something that would be subject to wear and leakage in the filter where it will be replaced frequently.
It probably isn't impossible, but why would some manufacturers spec a filter without a drainback valve in applications where the filter hangs down? I'm still of the opinion that Ford specs one filter primarily to keep inventory costs down.
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02 F250 4X4 SC 7.3 PSD
93 F150 4X4 SC 5.0
93 Ranger STX 4X4 4.0
90 BII wheelin' rig
68 F250 4X2 360
68 F100 4X2 360
92 Ford NH L553 Loader
I bleed Ford Blue
Oppy, that's how a syphon works even if the filter is hanging down. Think about this: have you ever syphoned gas from the fuel tank of a car or truck? The filler opening is higher than the fuel tank, so in effect it is "hanging down". Now when you put one end of the syphon hose in the fuel and the other end lower than the fuel level, it starts to syphon once the hose is completely filled with fuel.
I know how a siphon works, thanks. But the hole in that theory is you forgot about the presence of a gear-type oil pump that has close enough tolerances to develop 60+ psi. This isn't the same as a garden hose in a fuel tank - think of trying to siphon fuel back through a fuel transfer pump instead of just a hose and you can maybe understand my reasoning. If oil pumps were so loose that oil could freely backflow through them, I think they'd be less able to make pressure.
Now, I'm not saying it is impossible for oil to siphon back into the pan - you can always tell a worn hydraulic pump on a piece of equipment because it leaks back - I just don't see it as being a huge problem.
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02 F250 4X4 SC 7.3 PSD
93 F150 4X4 SC 5.0
93 Ranger STX 4X4 4.0
90 BII wheelin' rig
68 F250 4X2 360
68 F100 4X2 360
92 Ford NH L553 Loader
I bleed Ford Blue
Originally posted by oppy I know how a siphon works, thanks. But the hole in that theory is you forgot about the presence of a gear-type oil pump that has close enough tolerances to develop 60+ psi. This isn't the same as a garden hose in a fuel tank - think of trying to siphon fuel back through a fuel transfer pump instead of just a hose and you can maybe understand my reasoning. If oil pumps were so loose that oil could freely backflow through them, I think they'd be less able to make pressure.
Now, I'm not saying it is impossible for oil to siphon back into the pan - you can always tell a worn hydraulic pump on a piece of equipment because it leaks back - I just don't see it as being a huge problem.
Oppy, if the way you are thinking was correct, then NO OIL FILTER
would need an anti-drainback valve, no matter how it was mounted!!!! Bottom line, oil does return to the oil pan through the oil pump!!!!
Originally posted by Bob Ayers Oppy, if the way you are thinking was correct, then NO OIL FILTER
would need an anti-drainback valve, no matter how it was mounted!!!!
Not really Bob - if the filter is oriented such that the inlet is down, the column of oil would be under slight pressure. If the inlet is up, you would need to create a vacuum to move the oil. Apples and oranges.
Honest - I'm not trying to be argumentative, you may be 100% correct. In my own feeble way, I'm trying to think this through.
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02 F250 4X4 SC 7.3 PSD
93 F150 4X4 SC 5.0
93 Ranger STX 4X4 4.0
90 BII wheelin' rig
68 F250 4X2 360
68 F100 4X2 360
92 Ford NH L553 Loader
I bleed Ford Blue
Originally posted by oppy Not really Bob - if the filter is oriented such that the inlet is down, the column of oil would be under slight pressure. If the inlet is up, you would need to create a vacuum to move the oil. Apples and oranges.
Honest - I'm not trying to be argumentative, you may be 100% correct. In my own feeble way, I'm trying to think this through.
Oppy, hopefully this will help you understand what I have been trying to say. It is the oil pump specs on a Toyota, as you can see, the gear to housing spec alone is 3.9-7.5 mils, plenty of space for oil to go through, especially when it's hot!! There is NO
WAY an oil pump will block the flow of oil back to the pan!!!
I too am skeptical of the siphon effect. When the inlet of an oil filter is oriented down you have gravity draining the filter. When the inlet is oriented straight up you will drain off the oil in the filter passage but the oil in the filter will stay there because of gravity. The siphon effect would be minimal because of the obstructions in the path to the pan. The standard GM long filter replacements come in two verities, one with drain back and one without. The one with the drain back valve is spaced for the old inline motors which mount their filters like a Ford 300.
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