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1962 Series 2 Oil Pressure

gearheadgirl

gearheadgirl

Donation Time
Just changed the oil and filter and refilled with 5 quarts of SAE 30wt.

Assuming that the oil pressure gauge is working properly...it is reading 20 to 25 pounds of pressure, warmed up, at 50 miles per hour. Good or bad?

Thanks!
 
alpine_64

alpine_64

Donation Time
That depends what revs you are doing and what gear.. oil psi is relative to engine RPM.

The rule of thumb is 10lbs per 1000rpm on the motors when warm and running.. wiht a ceiling of about 55-60lbs on a stock motor.

Now, given you are saying you are getting 25lbs at 50mph.. if you are in top gear i'd say its a little on the low side. What are you getting at warm idle (and what rpm is your idle?) Are there any ticking/knocking noises from the motor as its revved?
 
gearheadgirl

gearheadgirl

Donation Time
No ticking or knocks. Plenty of white smoke when revving the engine or taking off from a stop light. It's an old motor that I'm sure needs to be gone through.
 
alpine_64

alpine_64

Donation Time
gearheadgirl said:
No ticking or knocks. Plenty of white smoke when revving the engine or taking off from a stop light. It's an old motor that I'm sure needs to be gone through.
Click to expand...

White smoke or light blueish/grey? White smoke would tend to indicate you are getting water to the exhaust.. which in alpines means head gaskets. grey smoke will be burning oil, valve stem seals can often cause this.

Check the oil in the sump and the underside of the cap.. you said it has just been chaned.. is the underside of the oil cap showing any condensation?
 
RootesRooter

RootesRooter

Donation Time
It sounds tired. Warmed up, highway speed rpm's should yield 40lbs from a fresh 1592. 40lbs is what your pressure relief valve is rated at.
 
Nickodell

Nickodell

Donation Time
25psi at 50mph is not "a little on the low side," it's LOW. As a contrast, my 1725 engine is 36 years old and has 85,000-plus miles, and gives 20psi at idle and 45 (OPRV blowoff) at 2500rpm. Admittedly, I use 10W40 oil, but that wouldn't make a great difference.

I think either your bearings are worn or the oil pump is not up to snuff. Just keep an eye on the pressure and an ear for mechanical sounds like knocking.
 
todd reid

todd reid

Gold Level Sponsor
1. White smoke can be caused by water/coolant or brake fluid getting into the cylinders. I don't think Series 2's normally came with servos, but if your car has one it is worth checking out before condeming the head gasket.

2. I agree that 25 lbs is low! Should be 40 at 60 mph.

3. If you recall your 8th grade science, pressure varies inversely with temperature. Those of you modifying your PRV's to jack up your oil pressure, especially the older series cars without oil coolers, need to keep this in mind! TT recommended 50 lbs at highway speeds, which is a 25% increase over the factory setting and plenty for non-racing engines. This is a definitely a case where you can get too much of a good thing!
 
R

RootesRacer

Donation Time
todd reid said:
3. If you recall your 8th grade science, pressure varies inversely with temperature.
Click to expand...


Huh?

Boyles taught me that pressure varies linearly with abs temperature (not inversely) thought this is for gasses not liquids especially viscous ones.

The oil pressure has no baring on oil temperature though. Oil pressure is for the benefit of producing flow between the bearing and journals to cool both, and provide an oil film for the interface.

The only reason that its a bad idea to run excessive oil pressures is the load it places on the cam and pump drive gears.
 
Nickodell

Nickodell

Donation Time
I think Todd was referring to the effect temperature has on oil viscosity, and hence on pressure. Hotter oil will be less viscous and better able to flow through pipes, galleries and bearing clearances, so one would expect lower OP at the same rpm with hot straight SAE oil than cold. Which is one reason why I have always used multigrade oils.

I'm old enough to remember when no such products existed. You used SAE30 or 40 (depending on the age of your engine) in the summer, and changed to SAE20 in the winter. I remember the changeover ritual - rather like replacing your storm windows with bug screen, and the reverse. My Triumph motorbike was different - it used straight SAE50 year round. Air cooled engines are different.

I know, I know. There are a number of people who will insist that multigrade oil will leak out of our engines. That makes no sense logically. At the temperature the "40" in a 10W40 oil refers to, the oil will be no "thinner" than straight 40. And if you decide to boost the OPRV spring rate, a multigrade will certainly help to avoid overpressure trouble in cold weather.

(Anyone using "weight" should have the fleas of a thousand camels infest their armpits, to quote Johnny Carson.)
 
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