Oil pressure, temp and viscosity

[Simple_Smith]

Reviving an old thread in hopes of some advice/answers

Turbo M20 with a small oil cooler ~7"x5"x1" running castrol 20w-50 in 80+ degrees ambient temp

I've noticed after a few runs (drifting) and idling in grid, my oil pressure drops down uncomfortably low (enough that my idiot light will come on at idle) but if i keep it at ~1000rpm pressure stabilizes around 10 psi. My fear is that I'm cooking my oil and my oil cooler is inadequate. I just ordered an 80psi oil pressure gauge (currently have a 150psi gauge that doesn't give me enough resolution in low pressure situations i.e. idle) and an oil temp sender that I will be installing in the drain plug. I know that isn't the most ideal location to get oil temp, but its the best for me not having to re-engineer a bunch of lines and whatnot to gain a 15 degree more accurate measurement. My other concern is that my m20 with unknown miles is on its last leg and the bearing clearances are getting to be too excessive.

I've been doing as much reading as possible to find answers to bump up the oil pressure for the time being. Some spec e30 guys are saying to delete the Oil Pressure Relief Valve with a M20x1.5 drain plug bolt. Still trying to read into it more and get a better understanding of the m20 oiling system before doing something like that. There is a website selling M21 diesel oil pumps for the m20 as an upgraded flow unit.
http://server.pure-pf.com/webshop2/i...id_lang=1&n=20
Not sure how much I believe that considering thats the only place I've managed to find such information.

Will report back once I get my oil temp readings and a bit more data to get me pointed in the right direction. A bigger oil cooler is definitely in the works, but depending on my numbers I come back here with will be how crazy I need to go with the cooler setup.

Thanks for any input.

[validius]

Reviving an old thread in hopes of some advice/answers

Turbo M20 with a small oil cooler ~7"x5"x1" running castrol 20w-50 in 80+ degrees ambient temp

I've noticed after a few runs (drifting) and idling in grid, my oil pressure drops down uncomfortably low (enough that my idiot light will come on at idle) but if i keep it at ~1000rpm pressure stabilizes around 10 psi. My fear is that I'm cooking my oil and my oil cooler is inadequate. I just ordered an 80psi oil pressure gauge (currently have a 150psi gauge that doesn't give me enough resolution in low pressure situations i.e. idle) and an oil temp sender that I will be installing in the drain plug. I know that isn't the most ideal location to get oil temp, but its the best for me not having to re-engineer a bunch of lines and whatnot to gain a 15 degree more accurate measurement. My other concern is that my m20 with unknown miles is on its last leg and the bearing clearances are getting to be too excessive.

I've been doing as much reading as possible to find answers to bump up the oil pressure for the time being. Some spec e30 guys are saying to delete the Oil Pressure Relief Valve with a M20x1.5 drain plug bolt. Still trying to read into it more and get a better understanding of the m20 oiling system before doing something like that. There is a website selling M21 diesel oil pumps for the m20 as an upgraded flow unit.
http://server.pure-pf.com/webshop2/i...id_lang=1&n=20
Not sure how much I believe that considering thats the only place I've managed to find such information.

Will report back once I get my oil temp readings and a bit more data to get me pointed in the right direction. A bigger oil cooler is definitely in the works, but depending on my numbers I come back here with will be how crazy I need to go with the cooler setup.

Thanks for any input.

You didn't give us a baseline. What is the pressure when cold?

[digger]

i dont see how deleteing the relief valve helps hot pressure. when cold the pressure is likely 70psi at all rpm inc idle as that sees to be the relief pressure and when cold even 10W-40 is thick enough to set off the relief valve. i havent checked the spring tension to see if that is the true pressure but my gauge reads 65-70psi. as the oil gets thinner the relief valve doesnt get used anymore (except perhaps at WOT high rpm). if the pressure is below the relief valve pressure limit it is dictated by the engine speed and viscosity ( for a given engine). i belive there are more than 1 relief valve so not sure how all those fit into the picture

also ive seen more than 1 broken oil pump drive shaft. thick oil + high rpm + no relief vlave loads up the pump and shaft more as the system has alot of back pressure

[digger]

im also interested in the diesel oil pump and what effect it has and if its PnP. MM sell a modified spray bar to stop the oil being pumped into the head excessively

[Simple_Smith]

sorry about the late reply, my cold oil pressure is around 65-70psi. Since installing the new pressure gauge and sender (80psi instead of 150) I haven't driven the car hard enough to get it to drop the pressure down. Thus far at idle when the engine is at operating temp oil pressure is stable at ~20psi.

Digger, the M21 oil pump, to my knowledge, is a direct Pnp. M21 is very similar to the M20 as you know, but the thumbnail pic on the website isn't working for me anymore just to visually compare it.

Still haven't gotten around to installing my oil temp gauge and sender. I'll update again when that gets put in and I have some data.