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1929 640 oil pressure issues


Guest REO&packard

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Guest REO&packard

Hey guys I started the Packard up after a long nap. Now my oil pressure is running 50lbs+ at idle! Anyone have any sugestions on what I should look at first. The guage moves up in pressure slowly as I crank, once she fires it goes off the scale.

Thanks for the help.

Joel

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Sounds like you better inspect the oil pressure relief valve before you burst the bourdon tube in the gauge! In 1934 the relief valve moved to an external location but I believe yours in internal on the pump body. Perhaps the plunger is stuck in the closed position, or perhaps it just needs adjustment.

Mine is set to give a maximum pressure of 55 psi.

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Guest REO&packard

Checked it the other day, adj of the relief does nothing to change the high pressure situation. Any other thoughts would be appriciated!

Thanks Joel

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How long was the nap? Did you clean the pump screen? It is also possible that the relief valve is stuck. You should be able to disassemble it with the pump still in the engine and then clean things up. It consists of a locking nut (remove first), then the adjusting post (unscrew all the way), then a spring, and finally a ball bearing.

Tom

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Guest REO&packard

Thanks for all who offered there help. You never can be too sure that you didnt over look something simple. I am guessing the plunger is stuck, so that will require a little bit more work. I will take it apart this weeked and report back as to my findings.

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  • 2 weeks later...
Guest REO&packard

I drained the oil and opened the case cover, there was a lot of sludge and buildup in the spring and check ball sleeve. I cleaned up the parts and reinstalled them. The spring tention is six full thread turns in. The final virdict------ No change! I am going to pull the guage and see if its not a false reading.

Joel

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One word of caution. I had a similiar problem and bought another oil gauge from NAPA to see how accurate the in dash gauge was. The new gauge showed that the in dash was off...or at least I thought. Using a third gauge, that gauge agreed with the dash gauge. So 2 out 3 grin.gif

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Guest Trunk Rack

thank heaven at least ONE of you ( OWEN ) knows what he is talking about.

There is no "pressure adjustment" !

As OWEN points out - it is only a PRESSURE RELIEF valve. BIG difference. The ONLY function of that device is to serve as a "blow off" valve, to protect the engine oil line piping (and full flow oil filters on the later pre-war "Senior" Packards) from excess pressure resulting from too cold and/or too thick oil. Engine designers knew even then that some "backyard mechanics" think it is cute to use too thick oil. Be assured "too thick" oil WONT solve bad bearings and an otherwise worn-out motor.

To properly set this RELIEF VALVE ( again, thank you, Owen, for using the correct technical terminology, at least one of you seems to know these engines), let's review some basics.

First and foremost, you set the oil line "blow off" pressure when the engine is stone cold.

Secondly, use the correct weight oil. Remember, so called "SINGLE GRADE" oil is a misnomer - it changes viscosity like crazy depending on the ambient temp (that is why I prefer "multi-grade" oils, which actually hold to a more or less constant viscosity regardless of temp).

The "Senior" Packard eights of that era had barely adequate-sized oil pumps. I would be surprised, actually AMAZED if you could see 50 lbs with hot oil, even on a tight motor with good cam bearings.

So, I go along with what some of you have suggested. Drop that big long oil pan, and keep it clean - doing that at LEAST every two years or so ( those ultra-long pans dont drain all that well if you just drain from the drain hole and the little steel 'sump plate'.

With a CLEAN oil pan, now you can put in some 10-30 (or if you are going to go blasting across the desert at extreme speeds 20W-50) and set that RELIEF VALVE at whatever you like. Again, when the engine is stone cold.

You CANT set it with hot oil, because the oil pump will NOT be able to run the pressure up high enough to "blow off" the relief valve. Thus you run the risk of setting the "blow off" pressure too high. Then, with a very cold engine with thick oil, you might have set it too high. With really cold thick oil, you could wind up with a situation by which you blow an oil line, and/or damage the pump drive. So again, dont mess with this thing when the oil is hot and thin - you could screw the damn thing all the way in, with hot oil, and you are not going to see pressure beyond what the pump can deliver.

What to set the valve to "relieve" or "blow off" at ? 50 lbs isnt going to hurt anything (IF you can get it that high). But dont expect to see 50 lbs on a pre-war "Senior Eight" once the engine gets hot. Maybe 30-35 if it is in super good shape. You probably wont see anywhere near that much at lower rpms.

And, as others have noted, what about guage accuracy ? Resolve that first.

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  • 2 weeks later...
Guest REO&packard

Trunk Rack, I am not sure who you think directed me to "Adjust" the pressure in this forum.

Everyone

I pulled the pan as stated before, the spring and ball setup was in need of service. After full inspection and reinstall of 6 full rotations (only because original was in 7 turns, to see if the spring was too tight or hung up in that old wear pattern).

My new guage reads the same!

My next step in to pull the pan once again and remove the check ball to see if the pressure drops off.

Not sure what else to look for?

My REO runs 40lbs cold and 30lbs hot on 30w ND oil. I am running the same in the Packard.

Thanks for the tips

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  • 2 months later...

Hey fellow car nuts!

I got sometime to tinker around with the Packard last night. I pulled all my oil lines and the problem was the filter itself! The valve when opened let oil drip out (saying the filler was good) BUT IT WAS PLUGGED UP SOLID!

I am at 41 lbs cold now and about 32 hot. thanks for the thoughts and comments!

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