Oil Pressure

[Guest]

I have a Mercedes OM 636 engine. In the service instuctions it says that the oil pressure must be 0.5 kp per sq cm at 600rpm at normal service temperature. My oil pressure guage is in lbs per sq inch and also in bar. I do not know how to convert this in fact I am not sure what kp is. Is it Kilo Pascals? Any Ideas?

 

[Isis]

Try this web site.

www.mathconnect.com/pressure.htm

 

[brianrunyard]

Are you sure it specifies 0.5 KiloPascals

1 Kilopascal (kPa) = 0.145 psi.
1 Kilopascal (kPA) = 0.01 Bar
Therefore 0.5 kPa = 0.0725 psi

 

[vyv_cox]

1 kp/cm2 = 1 bar, 14.22 psi. 7 psi sounds like a very low oil pressure.

 

[brianrunyard]

Just re-read your post, 0.5 kp per sq cm = 0.5 bar = 7 psi.
It's not Kilopascal which is kPa.

 

[Guest]

I agree that 7psi is low that is what confuses me, it definately says 0.5 kp per sq cm and is printed on the original daimler-benz service sheet, this is half atmospheric pressure is it not? Notwithstanding all this does anyone know what should the oil pressure be in psi or bar for a diesel engine at tickover at normal temperature? Tks

 

[boatone]

re OM636 I had one on my Norman 32 and the oil meter usually showed around 500 but not sure what units!
Visit http://www.west-4x4.demon.co.uk/om636/om636e.html for a lot of good info.
The guy at Westfield gave me some very helpful info re oil pressure to expect etc.

boatone@boatsonthethames.co.uk

 

[jfkal]

Correct it is Kilo Pond and if I am not mistaken it equals .5 Kilo Pascal

 

[johnt]

7 psi or .5 bar is acceptable at tickover, (it would make me twitch a bit tho'), but the o.p must be up to at least 35psi 2.5 bar at about 1200rpm, if not you have a worn engine, or a failing pressure relief valve.

 

[jollyjacktar]

Pascals ?

Your basic physics if you have any would not entertain the idea of kilo pascals per square centimetre. A pascal is not stated as pascals per square anything as it already has square metres inherant in its definition. One Pascal is the pressure exerted by one newton of force over one square meter of area. Thus one could say 50 newtons per square metre is 50 pascals, but never 50 pascals per square metre as this is a meaningless statement in the science of physics and as such says 50 newtons per metre to the power of 4, [four dimension space?????] . Now what is a newton? I won't complicate things further. Clearly, kp thus means something else and the threads already written point to this. Incidently one kilo pascal is equivalent to about 0.1450377 pound-force per square inch so that half a kP would be about the pressure of a gnats beath, and I think that you Merc would need a bit more than that to run happily.

 

[jollyjacktar]

Woops, my r\'s have gone to sleep

My last sentence should read "breath" not "beath" and "your Merc" not "you Merc", kP should read kPa.