Low oil pressure and different types of relief spring?

[Jon Tilson]

What i would want to see especially if I didnt trust the absolute gauge reading is the oil pressure building to about 3k rpm and then going no higher as the relief valve opens.

The numbers I would want to see on a sound motor would be no lower than 20 at hot idle and maxing out at 60 psi.

I would try a different gauge of you can.

Jonners

[gmsclassics]

Thanks Jon, tried an alternative gauge and that gave identical results.

Thinking about the early Jag XK engines that were fitted with a screw adjuster that effectively tightened up the PRV spring so you could set the pressure the spring released at, I dismantled my pump again and fitted a washer below the lower end of the spring. Seems to have worked as the hot pressure at 2650 rpm (60mph in top overdrive) is now 55psi, rising to a peak around 60.

Seeing as I also appear to have at long last managed to seal all the leaks around the pump and transfer housing, I think I'll leave it at that! Pity it isn't as easy as on an XK engine where all it takes is removing a domed nut from the underside of the pump to access the spring - 10 minute job!

Geoff

[Jon Tilson]

That soubds totally like a result. If you get that sort of pressure then there cant be much wrong internally and the jackshaft side thrust witll be acceptable.

Good job.

Jonners