P5B Oil filter by pass valve

[Jens]

I just chequed the oil pump from a P5B V8 for presence of the oil filter by pass valve. According to the WSM p.52 A1-19 the by pass valve should be at the end of the string but was absent.
Is the by pass valve simply missing or does the oil pump operate correct without that oil filter by pass valve ?

 

[SydneyRoverP6B]

The oil filter bypass valves were included within the oil pump front covers on both P5B and P6B engines. All later oil pump front covers omitted this valve, instead the valve being located within the oil filter itself. At the same time, the diameter of the spigot changed so fitting the correct oil filter for the matching front cover was not a problem. If as you say your oil pump front cover is missing the bypass valve, then that would suggest at some point the cover has been changed for the later version. What oil filter are you using? Do you know the diameter of the spigot?

Ron.

 

[Jens]

The oil filter bypass valves were included within the oil pump front covers on both P5B and P6B engines. All later oil pump front covers omitted this valve, instead the valve being located within the oil filter itself. At the same time, the diameter of the spigot changed so fitting the correct oil filter for the matching front cover was not a problem. If as you say your oil pump front cover is missing the bypass valve, then that would suggest at some point the cover has been changed for the later version. What oil filter are you using? Do you know the diameter of the spigot?

Ron.

Pls. consider the scan from the WSM p. 52. The oil filter by-pass valve should be located at the end of the spring indicated with E. (bottom picture)
It is the genuine distribution cover and oil pump. Oil filter is a Bosch large type.
The oil filter spigot diameter is 13/16"

 

[SydneyRoverP6B]

Hi Jens,

Yes that is correct, so what are you saying is absent? The bypass flap is not shown in that image, it is on the inside of the front cover. The oil filter bypass valve when looking inside the cover is nothing more than a disk. The spring sit against the inside surface of that disk. The filter bypass valve will not operate unless the pressure differential between the oil filter medium and the disk is in its favour. In other words, if the force required to push the oil through the oil filter is greater than the force required to open the bypass valve flap, the oil will bypass the filter, passing the bypass valve flap to be redirected back through the engine unfiltered.

Ron.

 

[Jens]

Hallo Ron,
In the WSM drawing E indicates the Oil Filter bypass valve as a disc located on the end of the spring. I used a magnetic pick up tool to find the disc. But in vain. On the foto the cap and spring without the valve at the end. The spring pushes against the valve so I looked inside the bore with a light but could not distinguish a disc. If the valve is absent no oil will flow thru the filter without any indication of a wrong situation because the enigine gets its oil (pressure). How can I cheque that the valve is present.

 

[SydneyRoverP6B]

Hi Jens,

The oil filter bypass valve is made from a non ferrous material, so a magnet will be of no use. It looks like a fibrous composite, being retained within the bore by a flange that is part of a ferrous insert. Unless the valve, which is just a disk is reality, disintegrated, then it is still where it should be. The only way you can check for sure is to remove the oil pump front cover and look inside. The link below provides a photo.
(60) Oil Pump Front Cover and Oil Filters | Classic Rover Forum

What makes you think there is problem? Is there no oil in your filter, or did you change the filter and when you later removed it, found it essentially free of oil?

Ron.