Engine Oil Pressure

[Squeaky]

Good morning:

Is the oil pressure in all diesel engine the same or do they vary depending on the make?

I am trying to establish what the oil pressure for my Vetus M2.06 engine should be but have not yet found anything of interest.

There are stacks of details in the manual but no mention of oil pressure.

While on the subject, would an "idiot" oil light affect the pressure shown on an analog gauge?

Cheers

Squeaky

 

[chrishelen]

you could google it, i think the engine is based on a mitsubushi fork truck engine ,that might give you some info.

 

[PTB]

Hi there,
I have the Mitsubishi 1500cc 4 cyl engine in the guise of Thornycroft. The workshop manual for all the 3 and 4 cyl Mitsubishis give oil pressure as follows with engine warmed up ......
At rated rpm 42 - 56 psi
At low idle should be greater than 14 psi

I think yours is the 2 cyl engine ??? but I'd be surprised if the designed oil pressures vary much.
The idiot oil light shouldnt affect the gauge reading but I have to say I have had previous trouble with the combined sender for switch and gauge on my engine .. just replaced it in fact.
Phil

 

[superheat6k]

The oil pressure signal from the transducer would be affected if the warning light were to take a load from the signal, but on my VP the signal reduces as oil pressure increases, so wouldn't work as a warning signal anyway. The warning light transducer is a simple NC contact closing below a certain pressure.

I did replace one of mine last year with an adjustable pressure switch (2 terminal) from RS. I set it up with a pressure gauge and bicycle pump. Most engines seem to run above 30psi, and I would suggest you want to know when the pressure falls below 20 - 25 psi.

 

[Otter]

At rated rpm 42 - 56 psi
At low idle should be greater than 14 psi

I've also got a Thornycroft (235 - 75hp) but not based on the Mitsubishi. New oil sender fitted and it reads 40-50 whether hot or cold, under full load or idle; when hot and at tickover it just touches 38/39 - are those readings normal? It's nearly 40 years old and I expected lower.

 

[Lakesailor]

Get a capillary gauge which transmits the real pressure to the gauge. I've always fitted them to car engines. It avoids suspicious readings. Use a "T" piece and fit the low pressure switch on one arm and the capillary tube on the other. Neither will affect the other.

Suggested readings are not the whole story A high pressure may indicate a blockage downstream, which may indicate starvation somewhere. Flow is more important than pressure.
Once you have established what your regular pressure is, changes can indicate a problem.

 

[Squeaky]

Hi there,
I think yours is the 2 cyl engine ??? but I'd be surprised if the designed oil pressures vary much.
Phil

Yes, mine is a two cylinder Mitsubishi so I will assume that the pressure should be similar.

The electrics to the key panel blew the other day for no apparent reason and it was discovered that the fuse in the black box at the top rear of the engine had blown. Have no idea what is in there except that I was told there is a 15 amp relay so inserted another 10 amp glass fuse which promptly blew. A friend came along to assist and he inserted a 20 amp glass fuse which works or at least it has not blown anything and restores power to the panel.

After messing around decided to check the manual and discovered that the fuse should be a "10 amp slow burn" fuse. I have never heard of such a fuse so will be asking around town to see if I can locate one. Have asked several people and several shops who also claim not to have heard of such a fuse.

Guess it is a case of "live and learn" but at my age I would have thought I would have learned just about all there was to learn but obviously much remains. Hope I live long enough to master most of it.

Cheers

Squeaky

 

[PTB]

it reads 40-50 whether hot or cold, under full load or idle; when hot and at tickover it just touches 38/39 - are those readings normal? It's nearly 40 years old and I expected lower.[/QUOTE]

I think lakesailor has it right .... if your readings havnt changed much over time then there is unlikely to be anything wrong. Did your readings change when you changed the sender, I wonder? You can buy on ebay ( around £30) a capillary type gauge for just testing / calibrating it if you want to see real pressure without any inaccuracies of the electric sender (or borrow one from a car mechanic).

My tickover pressure seems high as well, around 35psi. Sometimes I think too much instrumentation is there to worry you .. lots of new smaller engine only have a 7psi idiot light. ! P

 

[Cymrogwyllt]

"10 amp slow burn" fuse.

aka slow blow fuses

Just type 'slow blow fuse' in to a well known search engine.