85 617 Expected oil psi?

[Gmerrell]

Put 85 turbo 617 in a Ford truck. I installed an electric oil pressure sender at the oem location and a 80 psi oil pressure gauge and it's pegged high.

What pressure should I expect and if it's not more than 80, what could cause it to be high.

Thanks greg

[Usaguy]

according to the service manual oil pressure relief valve opens at 7 bar (100 psi)

3000 rpm - minimum 3 bar (43 psi)

from experience these engines have 2 bar (30psi) of oil pressure at idle warmed up.

[Diesel911]

The pressure relief valve in the Oil Pump is supposed to open at 101 psi - 7 bar. So assuming that is working that would be the max possible Oil Pressure. (not to be confused with the bypass valve in the Oil Filter Housing.)

On mine when I raced the engine it the max I got hot or cold was 97 psi.

If I remember correctly it take 21.8 psi to get the oil spray nozzles to work.

There was a few thread on it. It was too long ago to remember the details.
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[barry12345]

I would be more interested in the hot idle oil pressure. On these particular engines. It is normal for the factory gauge to be pinned at cold start idle and decline at idle after warning up.

I did not know the oil pump relief valve pressure blow off before this thread. I think a good engine shows about thirty pounds at hot idle. Somewhat less indicates some wear but is not serious. Until you get below perhaps 10 to 15 pounds.

Mercedes in general paid good attention to their oiling system design.

[t walgamuth]

When pretty fresh I believe the 2 bar at hot idle is common. I believe it says minimum to be 1.5. Like Barry said the mb oiling system is excellent.

[barry12345]

I do not remember ever catching any of my 616 or 617 engines below 2 bar or 28 pounds at hot idle. Never above that at hot idle either basically. It could be higher I suppose if the idle speed was above specs. Or conversely lower if the idle speed was substandard.

Usually they all read about the same in my case. Less is allowed in their service literature.

I would check for accuracy of the measuring system if I were getting a low reading at hot idle first.

A maintenance item is too change the O rings on the stalk or stem of the oil filter pipe. That traverses down through the filter and is removed with the filter lid. The size of the O rings are posted in the archives. Probably buy them almost anywhere. Have to be the cheapest item on the car.

I suppose they are there to prevent oil filter drain down but not certain. They go rock hard and brittle with age. Pretty easy to change.

They apparently get blamed for some issues. I have never seen the issues. All I am certain of is they are there to seal. If hard and brittle they will not be doing it as well.

[Dan Stokes]

On Mutt's engine (OM617) I get 20-30 at idle when warm and 80ish going down the track at full rack. Upon cold start it'll peg the gage briefly then drop to around 80 as it warms, then to the mentioned 20-30 when fully warm. This is on a well-worn engine with at least 220K miles on it, the last 150 miles or so with the engine at max speed and load.


Dan

[MB140300SD]

Actually min pressure is .3 to .5 bar depending on the engine.

[Diesel911]

Originally Posted by MB140300SD

Actually min pressure is .3 to .5 bar depending on the engine.

Yes I remember that being mentioned in previous threads.

The issue there is that I doubt if the mechanical Factory Oil Pressure Gauge has enough accuracy to tell the above amounts for certain. If the hot idle gets that low it would be a good idea to check it with another gauge that has finer increments.

That is approximately 4.35-7.25 psi

When the hot idle was lowish in mine I changed the O-rings at the bottom of on the Oil Filter Tube and that brought it up.

You can also raise the idle speed and us single viscosity oil that has a higher viscosity then you had been using (what they did in the old days).