Low oil pressure on idle

[126per]

Greetings all.

Last post made in same topic 2011, so i take the liberty in renewing thread.

I have no idea with what parts/special parts my engine has been overhauled with, but its an air cooled 126p, Panda30 head, weber40 that supposedly has done some 9000km since rebuilt.

Does anyone know how much pressure oil pump produces at idle and say 2000 rpm ? Thinking of connecting a reliable oil pressure test equipment.
Is correct thread for sender unit M12  1,5mm ?

Have a weird pressure sensor from later 4 cylinder Fiat models and is hoping part of the problem lies there.
Oil pressure gauge is graded in atm and 1 atm is about 15 psi so lets use psi.

Cold engine i get about 60 psi and on idle barely 13 psi. This is good from what i understand
On warm engine the red low pressure light flickers. Idle set to 1000 rpm.
Now if i rev engine to 2000 or even 3000 rpm i still dont get more than 14 - 16 psi. This is however not good.
Do i even dare to drive engine like this ?

Never ending discussions regarding the use of mineral vs synthetic oil but i use mineral 15W-40 and tried 20W-50 without any noticeable change.

[126per]

No one !!??

Was hoping to get some assistance on this forum. My experience on these engines is nil.
I would assume reason being oil pump cant keep pressure up when engine gets warm it is either due to leakage through a crank shaft bearing or pump itself is broke. Might also be that pressure relief valve is stuck.
Anyone with engine experience that can lead me in the right direction ?
How difficult is it to remove oil pump in order to check it out  ?
Can removal be done with engine in car ?

I really appreciate your help here 

[thepuddlejumper]

Hi, sorry no replies so far. From my experience it is usually the big ends worn. There has been some discussions on other strings where people have used either a 500 oil pump in a 126 resulting in low oil pressure as the pump internals are smaller. I would drop the sump  and check the shells for wear, hopefully it will only be wear on the shells therefore may only require replacing them, best of luck.

Ralph

[Gadge]

No one !!??

Was hoping to get some assistance on this forum......

126per what makes you think that anyone would know what the correct oil pressure should be?

[thepuddlejumper]

126per, the oil pressure at 110 deg C should be 35.5 - 43 lbs/sq inch or 2.5 - 3.0 kg/sq cm according to my workshop manual. Hope this helps.

Ralph

[126per]

Gadge - this is a 126 forum so i dont understand your comment.

Ralph - Thanks !

[Gadge]

You seemed surprised in your second post that nobody had replied to your question and I'm saying why would they? It's not a common question to ask.

[DEYAN IYI]

Please, let me add the following. A book from 1985 states:

"The normal oil pressure is 0,25-0,3 MPa (2,5-3 kg/cm2)." No rpm mentioned. They also say that if the pressure is higher than that, the relief valve will open.

The warning light sender picks up below 0.3 Bar (~0.3  kg/cm2), so that must be at idle speed of not less than 800rpm.


Here is also for the Bis, having in mind that the oil pump is totally different:

0,4...0,45 MPa at oil temperature  of 100 +/- 2° C

[126per]

Gadge - see this is the very beauty of forums - you always learn something new.

Thanks Deyan Iyi.

I guess the right thing to do is to take engine out of car and have it thoroughly looked at.