I was thinking about an auxiliary cooler ... i find that the oil looses a significant amount of viscosity when the engine is worked hard ... i was thinking that cooling the oil more might solve this problem ... unless, it is normal for the oil pressure to drop significantly when the engine is hot.
The oil pressure at idle will drop once the truck warms up. Under load I usually run at about 1/3 of the way up the oil pressure guage. At idle it'll drop to the bottom of the marks on the guage, perfectly normal.
What oil are you running? I run 15W-40 all the time. If you run 5W-40 or some other light oil that could be your problem.
Thanks alot .... that answers my question. I do run 15w40 throughout the year. I am happy that this drop in pressure is normal. (i'm a relatively new in the 3B department) I am guessing that when the engine is hot, you should set the hand throttle at a higher rpm when running at idle for any length of time.?
By the way ... how is the ATX turbo working out for you?
I have a graduated oil pressure gauge on the feed line to the turbo on my 3B. I was running Rotella 15-40, but I was concerned that I had too much oil pressure. The gauge was still showing about 75 psi at highway speed (about halfway between the marks on my original FJ60 panel meter) even when completely warmed up. I was afraid that kind of pressure might be too much for the seals in the turbo.
I switched to 10-30 Mobil 1 and now I show about 50 psi at highway speed.
It's probably a little colder here in Northern NY then the Maritimes by you, but oil viscosity does make a big differance in pressure.
I would not worry about setting the throttle higher when it's idling. At idle there is NO load on the engine so it doesn't need as much oil pressure to protect it.
The AXT turbo gives a good boost to the power and it doesn't seem to affect fuel consumption at all! I run at 8 psi boost and I limit my fuel delivery to keep the exhaust gas temperatures down at 1150F or so preturbo (between the head and the turbo).
I've installed a boost gauge and an exhaust gas temperature gauge (pyrometer) to know what is happening.
i have a huge externally mounted oil filter which i assume workes as some kind of cooler, but it doesn't do anything for the pressure. After about 12hours straight highway, the guage sits just above the half way at 2.5 thou and half way between nought and 50% at idle.
thanks for that ... my 3B is transplanted in a 77 FJ40; therefore, i am using the FJ gauges. I think that the oil pressure guage may read a bit different then the BJ gauge (just grabbing at straws here). Anyway, on the highway, the oil pressure is just below half ... and at idle its just about 1/16th on the gauge.
Maybe a mechanical oil pressure guage might be the way to go ... just to make me feel more confident that i'm not destroying my engine.
It came out of a 60. However, i am in installing a mechanical guage anyway. After driving with a 2F for so long, i am used the the oil pressure guage never moving from center while the truck is running (regardless of temp, rpm, or load). Maybe i'm just paranoid; but, i like to know what is going on under the hood.
The only gauge that is different in the bj/fj 40 series is the oil pressure gauge. There is a 12volt sender and gauge, and there is a 24volt sender and gauge; however, they are common to the different engines (B,F,H). The only other real difference in the bj42 instrument cluster is the 24/12volt dropper. You have a 12volt sender from the bj60 engine, and a 12volt gauge from the 77fj40 instrument cluster. It should be configured properly. The 12volt oil pressure gauges have an internal resistance of 44ohms and the 24volt oil pressure gauges have an internal resistance of 66ohms.
According to the Toyota B series engine repair manual, normal oil pressure for a HOT engine is:
at idle 4.3psi minimum
at 3000rpm 36-85 psi
(Normal oil pressure for the F series gas engine is 44-50)
The B series uses the same oil pressure relief valve as the F series, but they use different springs, hence the different operating pressures. The B series and H series use the same springs, and the H series also operates from 4.3-85psi.
I have an 84bj42, and it behaves as you describe. It pegs out when cold and above-idle rpm, and then drops down to almost nothing at hot idle, and that is with 15W-40 synthetic oil. With normal pressure ranging from 4.3 to 85, there is a lot of room for movement on the gauge.