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CASE 1690 engine oil pressure reading

Posted: Tue Feb 17, 2015 12:18 am
by providencefarms
I recently installed an oil pressure gage in the cab of my 1690 because I wanted to monitor the oil pressure closely. I read approximately 40 PSI. Is that where it should be? The weird thing is that I get about 40 PSI (45 at the most) when the engine is cold and it seems to stay the same (maybe a litle less 37-38 PSI) even when the engine is warm... Is there something wrong with my oil pump? Thanks for your input.

RE: CASE 1690 engine oil pressure reading

Posted: Tue Feb 17, 2015 7:12 am
by ollek
A pump that is in good condition will on higher revs constantly produce a pressure that is above the opening pressure for the pressure relief valve. This is why the pressure is the same with cold and hot oil as the relief valve is controlling the pressure. The pressure will normally be a little less when the engine is idling. A 40 psi pressure on lets say 1800 rpm does not sound bad to me, but I have no official figures at hand.

RE: CASE 1690 engine oil pressure reading

Posted: Tue Feb 17, 2015 11:18 am
by providencefarms
Thank you Ollek, that makes sense.

RE: CASE 1690 engine oil pressure reading

Posted: Tue Feb 17, 2015 5:44 pm
by bedwards1966
I don't know the figures for that engine, but I'd be quite content with those readings.

Re: CASE 1690 engine oil pressure reading

Posted: Sat Mar 09, 2019 7:36 pm
by Ian
Just as a note to anyone Reding this the pressure relief valve on a 1690 is set at 55 psi I have a gauge fitted and was getting 55 to 60 psi cold dropping to 50 psi hot at 1800 revs I suddenly noticed a drop in pressure of around 10 to 15 psi on inspection I found one of the screws missing on the upright after putting the screw back in place the pressure did not go back to were it was so I set off to check the oil pump whilst striping it down I found the high pressure pipe to pump union was only finger tight and dripping oil I know from the gauge that the pressure never dropped below 25 to 30 psi .I also found signs of gray around the big ends so stripped them out to check and found no4 bearing shell worn to half thickness the engine had developed a knock at higher reves the engine is now totally striped awaiting a rebuild