A quick question regardng oil and oil pressure

[queenskid926]

To keep it short, I do allot of corner carving and touges with the supra so i add an extra quart of oil after i top it off to reduce the chance of the oil pump pickup not being submerged during hard braking or cornering. I notice that after adding the extra quart, my overall oil pressure for idling and driving have increased quite a bit.

I was also contemplating on shimming the oil pump to also increase the oil pressure but since i already have an increase of oil pressure due to running an extra quart of oil, would this result in too much oil pressure?

Basically how much is too much oil pressure for our engines?

 

[jdub]

When you say "quite a bit", exactly how much pressure (in psi) did you have before and after at idle and 3000 rpm? And what weight oil and brand filter are you using?

You can have too much pressure on a 7M, but it's hard to achieve. Generally, shimming the pump 5mm on a stock system is safe.

 

[queenskid926]

Im using Castrol Gtx Full Synthetic 10w-30. I prolly exagerated when i said "quite a bit." Im just a freak about every lil thing when it comes to my supra. I still have the stock oil pressre guage so its a lil sketchy but at 3,000rpms it was around 2-2.5 kg/cm3 and after adding the quart its about 3-3.4 kg/cm3. Shimming the pump 5mm will result in how much more pressure?

When you say "quite a bit", exactly how much pressure (in psi) did you have before and after at idle and 3000 rpm? And what weight oil and brand filter are you using?

You can have too much pressure on a 7M, but it's hard to achieve. Generally, shimming the pump 5mm on a stock system is safe.

 

[jdub]

Is the above figures hot or cold? And (once again) what pressure are you showing at idle and what oil filter are you using? If you want me to help you, please don't make me drag info out of you...I also speak in psi, not Bar.

The pressure increase from shimming the pump depends on if the oil system is stock (i.e. is using the stock filter head) and the condition of the pump. You have to remove the oil pan to get at the oil pump...not an easy thing to do w/ the motor in the car.

BTW - Castrol GTX is not a "full synthetic"...the only true synthetic Castrol sells is Castrol European Formula (aka German Castrol) and it only comes in a 0W-30. All the other oils Castrols sells in the US are Group III base stocks. Take the time to read some of the other threads in this section.

 

[queenskid926]

sorry about that jdub, the above figures are once the car is warmed up. And now currently at idle its at 12 psi after adding the extra quart when it used to be 7.

I know that Castrol Gtx Full Synthetic is not truly a full synthetic, I read the other Stickies, its just that i receive 6 gallons of it for free, and im a poor college student. And im using a K&N Oil Filter.

My main Question jdub is on a stock oil system, with a good condition oil pump, How much psi will i gain shimming the oil pump with a 5mm shim. And also on a stock oil system, what would you consider too much oil pressure?

 

[jdub]

Free is good

Your oil pressure is not excessive...in fact, it's quite good for a stock system. The reason I asked about the filter is to make sure you were not running a crappy one and it causing a problem...A K&N is a decent filter though.

If you shim an oil pump 5mm, you can expect at least a 10-15 psi increase at idle and ~20 psi increase at 3000 rpm. Based on what you show now with a stock filter head, it might not go as high on the 3000 rpm side...the filter head has a relief valve feeding the cooler that opens at ~40 psi and dumps back into the pan. That feature effectively limits upper rpm pressures.

Based on your present pressure, I would not go through the effort of shimming the pump. More pressure is not always a good thing. If you start seeing 80-90 psi on the upper side, that is reaching the limit of what the oil channels in the engine can handle flow wise.

Vs shimming the pump, a better option would be to eliminate the stock filter head and go to a thermostat controlled, full flow cooler circuit with a remote filter head and larger cooler. That would give you a pressure increase due to dumping the relief valve in the stock filter head.

 

[queenskid926]

Thanks for the knowledge Jdub.
Now i see its time for me to do some research on the second option you mentioned. Again Thanks.
- Ronald