Unfortunately i had to do some major surgery on my xflow. Big end bearing down the drain causing a little crack in the crankshaft, or vice versa.
Found a used but immaculate crankshaft and replaced all main and big end bearings. Cleaned the oil pump and filled it with 20w50 oil before fitting. Started the engine with immediate oil pressure.

Oil pressure 15 psi at idle and 50 psi at 2000 rpm. Nothing to be ashamed of, i think.
But, above 3000 rpm the pressure is all over the place ! The gauge is bouncing between 50 and 0. At the moment the rpm drops below 3000 rpm, things are ok.
It's not an electrical problem. Sounds scary :-(

oil pump pressure relief valve?

edit: I mean: oil pressure relief valve sticky and not working quite right..?

[Edited on 27/7/14 by Dave Ashurst]

Yup, sounds like the pressure relief is not opening gradually, its just popping wide open at whatever pressure 3000 rpm yields.

quote:

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Originally posted by r1_pete
Yup, sounds like the pressure relief is not opening gradually, its just popping wide open at whatever pressure 3000 rpm yields.

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Ok, that's worth checking, although the pump is almost new (1000 miles). Thx

Split in the oil pickup tube maybe, worth checking as you have already lost 1 crank?

[Edited on 27/7/14 by mark chandler]