oil preassure on new rebuild
 

what is a good psi range for oil pressure on a new 2.7 rebuild @ idle and 3000 rpms? I have a front mounted oil cooler and peterson oil tank.

Even a newly overhauled 2.7 can seem to have low oil pressure, quite often it's a combination of the sender and the gauge.
7-10 lb. at idle hot is pretty common.
Oil pressure at 3000 should be at least 30lbs but I would expect to see higher.

10 lb + per 1000 rpm is the rule.

Agreed. What are you seeing?

-Wayne

Since i dont have a dip stick to check oil levels I have filled the tank to 2/3 of the top when idleing. 30 lbs at idle, as much as 60 lbs at 3000 rpm. the engine has only run for a few minutes at the reading.

My newly rebuilt 2.7 generally has 1 bar per thousand rpm.

That's about what I see in my 2.4 when cold. Are these cold readings? Should drop as it heats up.

What weight oil?

20 - 50

Looks like fine oil pressure to me.

I run a Peterson style tank too (4 gallon size), so checking the oil level is as simple as looking into the tank with the cap off. I have wondered what a good oil level would be, but have concluded that the higher the better until I start having too much oil in the breather/catch tank. So I usually fill it hot to just below where the intake comes into the tank. With this kind of setup, a higher oil level = less chance of uncovering the outlet under high cornering Gs. This should be especially important if you have a smallish (like 2 gallon) size tank (mounted up front, I assume).

Short of uncovering the outlet and starving the pump, the oil level ought not to have anything significant to do with oil pressure. It certainly won't make it be too high.

As with stock oil tanks, remember to keep checking the level as you get everything hot, thermostats open, oil coolers and filters fill, etc. When I change oil I usually blow out the scavenge lines into the tank after I have drained it, and some day I'll measure how much I get that way - maybe three quarts at a rough guess with my big coolers.

Walt Fricke

My 3.0 race engine idles warm at about 3.5 bar, and at 7300 rpm warm is 8 bar.

I am replacing the pedal bushings right now. I will run the car on wednesday and look at warm oil preasure readings. The peterson tank is a 3 gallon unit. It is hard to see oil levels through the perferated basket inside. any ideas?

Sure - isn't the basket below the inlet? Fill so the basket is covered? Anyway, here is what Peterson recommends on their website:

Peterson Oil tanks are rated in gallons of total capacity. A good rule of thumb is to run the tank about 2/3 full. When you first fill the tank, make a dipstick using a wood dowel or use a tape measure down through the cap and get a measurment as you put in each quart of oil. This can then be used to check the oil level on race night. After starting the engine, recheck the level and add oil as necessary to get about 2/3 full. If you find that you are blowing oil out of the breather, try lowering the level in the tank by about a quart. Blowing oil is often the result of the tank being too full.

This is pretty much what I did - when I started getting too much oil in the catch can (mine is a translucent plastic so I can see how much is in there) I lowered the hot oil level a little. Now I can just eyeball it.

Walt Fricke