Loss of oil pressure, what's wrong, what do I do next?

[chriswalker(lordcag)]

10 pounds of pressure for every thousand rpm
also arent synthetic's thinner even for a given viscousity as in a 20/50 synthetic would actually be closer to 10/40 or so I read that somewhere. which if that was true 5/30=0/20 which in tern would equall low oil pressure. also what was the engine built to run oil wise? 20/50-10/40 because a 5/30 in an engine meant for 10/40 or above could cause bearing problems mainly at startup which is when yours started I believe.

but I could be drastically wrong

 

[vortec]

viscosity is viscosity. synthetics aren't actually thinner than dino. they flow better because they don't have wax molecules and junk that conventional oils do.

the whole "don't change to synthetic in an old engine" thing is just an old wives' tale imo. if your engine is healthy (clean) then you won't have any problems with new leaks forming or junk breaking loose and clogging oil passages. i switched my k5 engine to synthetic about 10k miles after i installed it and i switched my pickup to synthetic at about 135k. they run great and don't leak.

the low oil pressure sounds like a clogged pump to me.

 

[Yo]

Well ignoring the advice I was given to be wary of using synthetic in an old motor, I switched to Royal Purple on a 140K Mercedes M117 engine and it never sprang a leak.

So yea, synthetic in old motors causes leaks is bunk.

 

[rufusbooth]

I would first verify the gauge is reading correctly, next i would change the oil filter with a Wix filter, then if the pressure is still low i would drop the pan and start inspecting for a pick-up tube that fell off. If the pick-up tube is still attached i would then start pulling some rod and main caps and look at the condition of the bearings (post pics and i'll look at them). If that all looks good THEN install a new oil pump AND screen and have someone tack weld the screen to the pump so that there is never a chance of it coming off in the future.

There are your steps...

Cheers,

Rufus

 

[GsxrMike]

I've run the motor twice with 50 psi oil pressure both times but I haven't had a chance to warm it up or wheel it yet. I have a slight crossmember and a slight driveshaft issue that I need to take care of first. As soon as I figure something out I will post results. I am also tearing down my 400 to take to the machine shop just in case.

 

[kamm]

If you do decide to pull main or rod caps, be sure to number them!!!!