Should I Install the New Oil Pump?? GOT A "NEW" NEW PUMP.......with photos

[thomas m]

Engine Specs Below.

My oil pressure has been marginal when the engine is operated at idle in hot weather. About 7-10 psi, sometimes a red light, according to an electric VDO gauge. No red light with the stock pressure sensor. 28 psi at highway speed. Other than that, even with so many miles all is well. No smoke, easy starts, low oil consumption, etc. No real issues.

I decided to take a look at the bottom end and the condition of the oil sump. I can't get any sort of rattle or looseness from the rod ends. I held them and jiggled the crank by hand. Still no looseness detected. All seems well. Is there anything else I should check since I have it opened??

The question:
I pulled the original pump. The 90 mm bolts seemed a little loose to me? Otherwise it's ok. I don't really want to pull it apart.....
Well, IFIRST  have a new German(Kolbenschmidt) oil pump sitting here. Should I put the original back in or should I use the new pump??
I'm curious if the more experienced among us would have an opinion on this.

PS:
Just compared the pumps......the only difference I see is the shape of the outlet port. I assume that it is the opening on the top of the pump, as installed. The original is more or less a round opening. The "new" pump port is definitely not round, but more of an hourglass shape; one end a little bigger than the other. Any comments on that? I've just added the photos................to me it looks like a flaw in the casting. I see not reason for it to look like that??

THIS IS THE OLD PUMP, ROUND OUTLET; KIND OF A ROUNDED TEARDROP:


THIS IS THE NEW PUMP, HOURGLASS OUTLET:

[ORCoaster]

If you have that low of oil pressure AND a new pump there is no question about it.  Install the new pump and watch the pressure climb.  Pumps do wear out and there is a process to figure that out.  But why bother figuring, Install it.

[thomas m]

I checked the gear widths........36 mm on the newer and 30 mm on the original. I'm hoping that, along with the closer tolerances, will boost the pressure a little. I just might opt for a different new pump. I don't like the looks of that casting.

[thomas m]

I did buy another pump. I just didn't like the looks of that "hourglass" casting.

For comparison, here's the outlet of the new pump that I installed.
I'm not sure why there would all of the above variations??

Not being a hydraulics engineer, I have no idea what the practical difference would be.

[ORCoaster]

And new pressure is??

[thomas m]

Haven't had a chance to test it hot yet.

Will report back.

Thomas
Vancouver, WA