Where do you buy your oil filter from?
Discussion
Interesting reading.
If Fram use silicone a Anti-Drainback Valve on the filter suitable for our engines this looks like a good choice.
Large surface area is mainly an advantage for long service intervals. Most of our oil changes are (should be) done on age rather than miles so the filters have less of a task. I would be much happier with a better quality ADbV than a few extra square centimeters of filter area.
The function of the ADbV is not compromised by the bypass not sealing.
The filter housing inlet pipework, between the pump and filter, will remain full as will the pump. Also with the "inverted" fitting in the Wedge the ADbV is helped to close by the weight of oil in the filter sitting on it and equally the seal of the bypass valve is only a problem when the oil is under pressure, as this is at the top, so gravity keeps the oil in the filter. This of course assumes that the oil does not seep through the filter media at atmospheric pressure which it may do over periods of layup.
Edit to add...
I've just looked at a couple of Fram PH2821A I happen to have in stock and there is a solid metal tube running up the centre of the filter which stops just short of the bypass valve. This will stop the filter emptying down it's outlet (*) because of seepage through the filter media.
(*) I have assumed the outlet is the central big hole! but I can't see how the ADbV would work the other way round anyway.
Champion C143 currently fitted.
If Fram use silicone a Anti-Drainback Valve on the filter suitable for our engines this looks like a good choice.
Large surface area is mainly an advantage for long service intervals. Most of our oil changes are (should be) done on age rather than miles so the filters have less of a task. I would be much happier with a better quality ADbV than a few extra square centimeters of filter area.
The function of the ADbV is not compromised by the bypass not sealing.
The filter housing inlet pipework, between the pump and filter, will remain full as will the pump. Also with the "inverted" fitting in the Wedge the ADbV is helped to close by the weight of oil in the filter sitting on it and equally the seal of the bypass valve is only a problem when the oil is under pressure, as this is at the top, so gravity keeps the oil in the filter. This of course assumes that the oil does not seep through the filter media at atmospheric pressure which it may do over periods of layup.
Edit to add...
I've just looked at a couple of Fram PH2821A I happen to have in stock and there is a solid metal tube running up the centre of the filter which stops just short of the bypass valve. This will stop the filter emptying down it's outlet (*) because of seepage through the filter media.
(*) I have assumed the outlet is the central big hole! but I can't see how the ADbV would work the other way round anyway.
Champion C143 currently fitted.
Edited by leorest on Tuesday 30th January 11:02
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