Longish skinny spring? I think you are referring to the bypass relief valve. It operates a piston to help regulate pressure. Do you mean it is not in it's little cylinder?

 

No it's their but could it be stopping the oil from circulating? What can cause theses units to fail, I suspect the cold because it was around 12 degrees I began to hear the noise.

 

A cracked oil pump ring would be stopping your oil from circulating properly.

That bypass relief valve can fail too.

The two at once not good.

fix that up and see if maybe you got lucky and didn't toast your engine.

 

is not the oil bypass springs job, too bypass the filter if it is blocked. So you would have to have a blocked filter and a bad preasure relief valve at the same time.

 

The oil pump gears are cast and they all seem to break. Mine was in three pieces and yes, they do not pump right when they're in pieces. I had @6psi cold when mine failed... replaced the pump and I sit at a full 20psi hot at 660rpm.

While the front cover is off, pop the c-clips out of both bypasses and clean them out and carefully reassemble. If you get one of the bypass plungers stuck in the bore when you put it back together, your oil pressure will be sky high when cold.

 

Finally!!! I got my car back together a couple hours ago after replacing the oil pump gear with a kit from rover parts. When I started my car I still hear the loud tap of the engine. I shut it off and checked the oil and the oil was certainly circulating, I turned it back on and my oil light went off. After letting it run for 5 or so minutes the tap got very quiet and disappeared. My theory is my pump went bad and didn't allow oil to get to the lifters and they dried up and started tapping, after installing the new pump they got oil and started working just fine. Thank you all for your help and keeping another disco on the road to break down another day.

 

good luck with it