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After starting up the engine (288 straight eight from 1949), in my Packard 8, 2292, I have realized that the maximum oil pressure I can achieve is 30 psi.
The manual says 45psi.
When starting it takes about 30 seconds before oilpressure starts building up!
Should I worry or can the oil pressure maybe be adjusted somewhere in the pump?

I hope that someone has some experience here.....

best regards
Henrik Thomsen, Denmark

Henrik,

Welcome to the Site. Lots of knowledgeable and experienced Packard people here who should be able to help you. If you haven't already could you post your 49 in the Owner Registry please?

Are you a member of any Packard clubs in Denmark, I know there's a Nordic Packard Club but not sure if it covers you.

And give my regards to Princess Mary when you see her next!

Het, Thanks for dropping in. I installed a brass "T" fitting and an oil pressure gauge at the engine block where the oil pressure sender is located. The dash gauge and the new oil pressure gauge have quite different readings especially when hot so maybe your factory gauge is no longer accurate after almost 60 years. The oil pressure can be altered by removing the pressure relief spring from the oil pump and a placing a washer under the spring. It will help up the pressure when the oil is cold but if your engine bearings are worn the oil pressure will still be low when the oil becomes hot. Thirty-five pounds pressure is not all that bad and certainly no cause for concern but the pressure should start to build within a few seconds of the engine starting. I would try adding a new gauge like I did and see what happens. It just may be a lazy sender or faulty gauge. What is the pressure at idle speed when the engine is hot and what grade of oil are you using; 10W30 etc.?

Clipper47,
I forgot to say that I already did fit the "T-connector" and mounted a real, and much more accurate pressure gauge.
I have heard about making the relief spring in the pump a little "harder" by placing a washer, but I simply have not succeeded to locate where to find the spring.

The oil pressure is more or less the same from cold to hot, and it drops very little when the motor is at idle RPM.

I am using 10W-30 oil.


best regards
Henrik

The factory oil pressure indicating system is based on an electrical resistance sender and these are typically slow to respond so I would disregard the observation that it takes 30 seconds or so to reach its maximum reading -- that lag is pretty typical of that system. A direct-reading gauge should respond immediately and if it doesn't, then I'd drop the pan and examine and clean the oip pickup screen - these can get choked with crud over time. Might as well clean the pan at the same time. And the fact that a warm engine at idle gives nearly the same pressure as a cold engine is a very positive indicator. If you want to shim the pressure relief valve to see if it's weakened, its accessed thru the large (7/8 or 1 inch) hex cap sticking out sideways from the pump. You should find the spring and a plunger. If indeed the pressure at road speed is 35 psi, I'd agree with the prior comments that it's not immediate cause for concern, it's adequate though not ideal.

If your engine is holding anywhere near 30 PSI at hot idle with 10W30 oil I suggest you have nothing to worry about. You might want to try an oil with higher viscosity like 15W40 if it really bothers you that it isn't higher. Drive and enjoy the car! On the oil pump located on passenger side of the engine you should see a large nut approx. 1" (25mm) size. Remove the nut and the oil pressure relief spring and a plunger is underneath and should fall out. Put a thin washer into the hollow of the nut and reassemble. Do you get an almost immediate pressure reading from the direct reading gauge? The dash oil pressure gauge on my 47 is slow to respond but the direct reading one at the sender "T" fitting is almost immediate.

Henrik,

Thanks for adding your '49 to the Owner Registry.


Again,

Henrik, I had a similar problem with my 22nd series '49.
Check out my web page about shimming the spring.

Click here

Hi Henrik

I get about 35psi at idle -40 psi at speed when hot or cold. Doesnt use oil and doesnt smoke. I use high viscosity Castrol GTX 20W50 as our climate is very hot. I do not worry too much and just enjoy driving. My other car (Chev truck with 235 si straight 6) has serious pressure issues (very worn)but i just drive carefull and relaxed. It has lasted for the last 2 years. Hope you get it sorted!

Hi Henrik:

The manual specifies maximum oil pressure of 40 psi with 5-15 psi at idle. If oil pressure at 35-40 mph is below 20 psi a mechanical problem is indicated.

Now the tap on the side of the engine is a calibrated orifice and not representative of true mainline pressure. Thus, the sender is engineered with a correction factor.
Thus, if you hook up a gauge to the sender tap you may think that you have low oil pressure until you look in the manual as to what the gauge reading should be at this point in the system.

Packard made some explicit recommendations against running too much oil pressure. The general rule is 10 psi per 1000 rpm with no more than 10 psi times the maximum rpm for the engine. This is very close to the Packard maximum of 40 psi if you consider that the eight revs up to about 4600 rpm with throttle wide open.

Here is a little test for mainline oil pressure: accelerate in second gear to passing speeds, if you start to hear noises from under the hood that may be worn rod bearings (especially if the noises don't start until then engine is hot). If your engine runs quiet then you have little to be concerned about.

If your engine is worn then take it easy and keep the road speeds modest. You may still go a long way with worn rods bearings given you don't push it. No guarantees of course.