91 cummins oil pressure

[MAvTistic]

I have a 91 cummins my question is what oil pressure others are running, the stock gauge stopped working so I install a mechanical gauge.

I just changed oil and filter runnin rotella 15-40 and running down the road i have about 50psi of oil pressure but at idle it droppes to just under 20 psi and the oil light comes on? do others have this much change or is something else going south on me?

thanks
MArk

 

[averagef250]

Cummins spec is 10 PSI@ hot idle and 35 PSI @ rated speed.

I've had a few dozen of these things and they're all over the place. I had a 4 banger that had 110 cold, 50 hot idle and 75 cruising. It always ran great and never missed a beat.

My 89 has a 92 dodge longblock in it with around 400K on it. I put the newer style thrust bearing in, but all others are the originals and look like new and the oil pump also looks like new. It has an air compressor on it which uses a good bit of oil, but it still has 60 PSI cold, 20 PSI hot idle and 45 PSI cruising.

If you really think you have lower than normal pressure pull the oil filter adapter off and inspect the pressure relief valve. On the pre-mid 90's engines most of them are broken allowing a lot of oil to bypass.

 

[crashnzuk]

I checked mine not long after I bought it, 50 hot idle, and 75 at 2k. I didn't check it cold.
Travis..