Engine: Oil a Pressure-So How Much Is Too Much?

[reichsrundfunk]

I think I'm getting great oil pressure in my 63 Lark's the 259 V8 with full flow filter but a friend thinks it's too high. I'm running 15W-40 diesel weight oil with ZDDPplus nothing else. Fully warmed up bet 160-180 I am idling (625rpm) at 35 pounds and on highways at about 65 mph I'm running at 65 pounds, and when it's really cold-below freezing its between 67-70 pounds.

Now I've had Studebaker v8s that I struggled to get to 20 pounds at highway speed and idled at 5 pounds or less. In those I dud experience bearing and crank failure eventually. So methinks more is better.

What say you all???

George

[swvalcon]

I would find a snap on tools gauge just to be sure. You shouldn't need more than 25-30 warm at idling and 50-55 running down the road. I wouldn't worry to much about cold unless it goes way up like 80-100. If that happen I would be looking at the relief valve. To high is hard on the bearings, oil pump etc.

[JoeHall]

How did you get those PSI numbers? I am guessing you have an aftermarket gauge hooked up. I say that because am pretty sure the Lark's gauge only has marks, and not numbers.

If the numbers are accurate, that is real good pressure, but bordering on too high, since the pressure relief valve is supposed to pop open at 50 PSI, IIRC.

[reichsrundfunk]

How did you get those PSI numbers? I am guessing you have an aftermarket gauge hooked up. I say that because am pretty sure the Lark's gauge only has marks, and not numbers.

If the numbers are accurate, that is real good pressure, but bordering on too high, since the pressure relief valve is supposed to pop open at 50 PSI, IIRC.

Not so sophisticated. Using the gauge in the instrument board. The marks are graduated in 10 pound increments. Ok not precisely scientifically accurate but somewhat representational of what's happening under the hood.

George

[Mike Van Veghten]

Yea, that sounds a bit high in the reality of a Stude engine.
I'd get a good quality (Autometer) mechanical gauge and verify those readings. Cold...above idle, a Stude pump will put out 60/65psi. But after about 20 minutes of driving, it WILL drop. How much depends on the engine. Age/miles...

Bearing (main & rod) clearance, rod side clearance, lifter clearance, cam bearing clearance, oil pump cover to gear clearance, rocker arm to shaft clearance...AND the viscosity of the oil all play into what ends up at the cylinder head to gauge port.

Now as to the PSI amount. Much over about 45psi, oil hot, at normal freeway speeds is robbing horsepower, gas milage.

Mike

[reichsrundfunk]

All true. When the engine is cold it's running 60-65 psi at cold idle which is around 800-850 rpm and 80 highway but it'll drop down to 35-65 when fully warmed up hot.

George

[Studebakercenteroforegon]

Hey, it's cold in Pennsylvania now! (Compared to western Oregon, anyway.) Consider using 5W-40 instead.

[PackardV8]

Yes, as has been suggested, 15W-40 is much too stiff for cold weather. It wears the timing gear, distributor gear and oil pump, plus takes horsepower to drive that 65 PSI.

Change to a 5W-30 and get back to us with the pressures then.

A Stude V8 in good condition shouldn't need 15W-40 even in summer unless it's a truck hauling a load. A 10W-40 should be fine in the summer.

jack vines

[studegary]

Yes, as has been suggested, 15W-40 is much too stiff for cold weather. It wears the timing gear, distributor gear and oil pump, plus takes horsepower to drive that 65 PSI.

Change to a 5W-30 and get back to us with the pressures then.

A Stude V8 in good condition shouldn't need 15W-40 even in summer unless it's a truck hauling a load. A 10W-40 should be fine in the summer.

jack vines

I agree with Jack that the oil is too viscous.

I also recommend servicing the oil relief valve. It does not seem to be working properly.

[Bud]

The 289 in my 62 Hawk full flow block has run oil pressure like that since I built it in the late 70's. I use Chevron Delo 400 15W-40 oil and the pressure I see with a warm engine on the freeway is 60lbs with 30 to 35 at idle and the relief valve is clean and not sticking. To be on the safe side remove the relief valve to be sure it's clean and not sticking. Bud

[DEEPNHOCK]

This is the number one thing you should attend to.
And service it according to "the good book" (Your Studebaker service manual)

<snip>
I also recommend servicing the oil relief valve.
<snip>

[StudeRich]

George's numbers match very closely to all (Many) of my full flow Stude. V8's going of course by the Factory Gauges, which I would guess are not 100% on the money, but quite consistent over time and from one Car to the other.

I have noticed no big difference when I went from Det. H.D. straight SAE 30 Wt. to the 10/30 in Washington, or 20W-50 in Calif. using Valvoline, Castrol or Quaker State.

Other than using 10W-30, I would not change a thing.
Studebaker Engines were never designed or built to handle 5W Oil or any Multiweight Oil containing 5W, except in extremely low Alaskan, below 0' Temps.

[JoeHall]

I agree, good idea to service the PR valve if concerned about oil pressure, especially if unsure what has & has not been done, nor when. However, once serviced, it should not need to be touched again till the next rebuild in 100,000+ miles. Modern oil will keep it, and everything else in the motor, clean as a whistle.

We all have our favorite oil brand and viscosity. I ran 20w50 Castrol in all Studes till switching over to 15w50 Mobil 1 around 1997. I usually break a new motor in with el-cheapo 10w30, then swap over in about 1000 miles. I have tried 10w30, 10w40, and 15w40, but they leaked more, held less oil pressure, and got less MPQ.

I also change the oil and filter at extended intervals: Castrol every 5000 miles, and the Mobil 1 every 10,000 miles.

[reichsrundfunk]

Noted, gents. Thanks for the input. This engine has not been opened up since assembly in South Bend. I don't mind changing to lower viscosity oil but that goes against lots if oil advice I've seen recently. Perhaps going to 10W 40 is in order. I don't like 10W-30. Too thin........

george

[Studebakercenteroforegon]

Too thin? In Pennsylvania in the winter? Maybe you should consider what makes the engine happy as opposed to what makes the driver happy.