1977 Triumph T140v - Wet Sumping Q's

@Charles West
Yes does good to clean up the release valve as if sat to long they seem to seize up a bit. And as you are fitting a superior oil pump you should get over any probs there. I take it you have checked it is a straight forward swap. Some you have to shave some metal of the inner cases just to fit them. But good luck and do keep us all informed on the progress. Joe

 

Wotcha Charles, welcome in.
The pressure relief valve is basically a piston with a spring behind it. If the pressure within the delivery side (timing side) of the engine is greater than the strength of the spring then the piston will move allowing the oil to bypass the crank and enter directly into the sump.
This mostly occurs when the engine is warming up when the oil is thick. The pump easily scavenges this temporary overflow of oil back into the oil tank as the return side of the pump has a greater capacity than the delivery side.
Once the oil becomes hot and thins the pressure drops. the spring in the pressure relief valve is then capable of pushing the piston back to the closed position. All the oil then passes through the centre of the crankshaft and sludge trap and on through the big ends as normal.
You can remove and dismantle the pressure relief valve to both clean and ensure that the spring is the correct length. A well aged shorter spring wont hold back enough oil pressure to prevent wet sumping.
I've had PRVs that measure ok but do not operate correctly (probably due to the piston getting lodged sideways somehow) and have cured wetsumping by just replacing with a new one.
A 1977 engine shouldn't require any work if you've ordered a normal two valve pump and not a 4 valve as fitted on later years or one of those Morgo rotary pumps. The rotary pumps are just not needed and IMO increase pressure to cause gasket problems.
Wet sumping is usually cured by a pump clean/test andreplacement. Although there are lots of causes - I did a thing on here sometime ago, I'll see if I can find it.......

Edit......yep here ya go

https://www.thetriumphforum.com/threads/wet-sumping.27444/

Extra Edit.......I see you've already seen the thread. The checks listed there are worth running through if your new pump doesn't cure the issue.

 

A two valve Morgo from Shropshire Classics should slot straight in.
Have a check of the two oil seals in the timing cover. The upper one is for the exhaust cam into the points. The lower one (which faces the other way towards the cover) and held in with a circlip can also cause wet sumping if it has been damaged or hard.
Enjoy