Jaguar Repair: 4.2 oil bypass valve, pressure relief valve, filter element

Question
I have a 1970 FHC 4.2 that I finnaly got back to. While installing a spin on oil filter, I pulled the " oil manifold" that connect the filter to the block(I was changing the bypass hose as well)  and good thing. The bypass valve was out of place and but still in the "manifold". Is this supposed to be a press in fit? I was thinking of peening it in since it will slide in and out of where it fits. your thoughts? THANKS!!!!

Answer
Hi James,
I don't know which valve you are talking about. So first we need to get together on terminology. The spring and valve directly under the hose fitting is the pressure relief valve which dumps the excess oil back into the pan. This controls max oil pressure so that the oil pressure does not go too high since the oil pump has the capacity to exceed 400 PSI. The large plug just next to the hose fitting is the "balance valve" which opens at a pressure differential of 10 to 15 PSI. When there is a different pressure on either side of the filter of 10 to 15 PSI, it opens to allow oil to bypass the filter element so the engine will not be starved for oil if the filter becomes clogged.

From your description I can't tell what you are talking about. The valve under the hose fitting is a loose valve on the end of the spring. The large plug next to the hose fitting is a closed complete unit with a valve and spring inside it and it is not serviceable and should be replaced as a unit if stuck or has come apart. This is a very important component as if it is a problem, unfiltered oil will either always be run through the bearings or if not opening will cause the bearings to starve for oil when the oil filter gets clogged.
Howard