Oil filter housing

[davidwheeler]

I have just rebuilt the engine of the VIIIth and, before trying to start it, I thought I woulld check that the oil filter housing, which I had filled yesterday, was still full.   It was empty.   I thought to check the VIIth which I had taken for a spin yesterday and that too was empty.    I guess this is a thing, that the oil must drain back through the pump and that is why it takes those 20 nailbiting seconds before the oil pressure needle springs across the gauge when first starting up.

[Dikappa]

Hi David,

I have the same issue, and find it very unpleasant too!  Iain Simpson in Australia claims that if the oil filter housing is completely airtight, the oil should not drain.  He recommends machining a groove in the nut on top for an o ring...

I haven't tried this myself, as i would reckon if air can get in, oil would come out, but he is very certian this should be the problem, and he has been right too many times to ignore....it is on my to do list, which is quite full with non, car issues though at the moment...so maybe you can investigate.

I also have had loss of oil pressure two times on a very steep downhill road, and have considered adding an accusump to the oil circuit... although that would be hard to hide somewhere out of side due to it's size...

[davidwheeler]

I have fitted a hinged baffle in the sump which has eliminated the latter problem.    It also stops the loss of pressure from a sudden stop which causes surge.   Also, I usually have the sump a little overfilled.

[Tony Stephens]

Motorcycles, which are quite often dry sumped, with a return pumped feed to the high-mounted oil tank, sometimes have a valve in one of the oil pipes to stop the tank contents draining into the crankcase when the bike is out of use. It makes you wonder about doing a similar thing to the external engine oil pipes of a Lambda engine.
Just thinking aloud, perhaps this does not make sense.

[davidwheeler]

That would risk the oil staying in the filter body and the pump emptying - I had considered that!    The pump is above the level of the oil in the sump so primes from the filter insofar as I can see.

[Dikappa]

But David, since the filter drains itself empty anyway, there would be no priming for the pump either in that case?
Also with installing an accusump a checkvalve in the line to the filter would be required, and this has stopped me from doing this till now...I plan to try Iain's idea first....

[davidwheeler]

Presumably enough stays in the pump chamber!
See technical info thread for filter number.