1957 364 HIGH OIL PRESSURE

[CYCLONE 1952]

SINCE I HAVE HAVE REBUILT A 364 I HAVE HAD A PROBLEM WITH HIGH OIL PRESSURE (90LB)@3000 RPM THIS CAUSES THE LIFTERS TO PUMP UP TO THE POINT THAT THE VALVES RIDE AND THE ENGINE RUNS ERRATIC AND STALLS .THE MASTER REBUILD KIT WAS SUPPLIED BY KANTER ALL THE MACHINE WAS DONE BY A VERY RECOGNISED AND RESPECTED LOCAL FIRM .I HAVE REMOVED THE OIL PUMP SEVERAL TIMES TO CHECK CLEARANCES AND THE RELIF VALVE . I HAVE TESTED THIS BY MEANS OF REMOVING THE BALL AND SPRING I PULLED A PIECE IF AIR HOSE THROUGH FROM THE BALL SIDE AND UP OUT THE PUMP BODY ON THE PRESSURE SIDE REFITTED THE BALL AND SPRING AND CAP I PUT A PRESSURE GUAGE IN LINE AND INTRODUCED AIR AT 40 PSI THE VALVE STARTED TO FLUTTER INCREASED THE PRESSURE TO 50 PSI AND THE VALVE FULLY OPENED,NOW THE THING THAT CONSERNS ME IS THE GENUINE BUICK CHASIS MANUAL STATES THAT THE RELIF VALVE IS SUPPOSED TO MANTAIN THE OIL PRESSURE TO A CONSTANT 40PSI

HOPE SOME ONE HAS GOT SOME IDEAS REGARDS TONY IN OZ

[Guest brh]

This may be a real stupid question but is the oil filter correct or not working? Sounds like the pump is doing its job and then some.

[CYCLONE 1952]

I HAVE RUN THE ENGINE WITHOUT A FILTER ELEMENT WITH THE SAME RESULT SO I AM TRYING ANOTHER TEST TOMORROW I'LL KEEP YOU POSTED THANK YOU FOR YOUR INTREST AND INPUT I HAVE POSTED THIS PROBLEM ON THE MODIFIED/ TECH HELP ALSO

[Leif Holmberg]

I can at least help you with this pictures.And I`m just thinking about the oil pressure valv and spring (O)are you sure you have the right spring in it.Or maybe the gaskets don`t have the holes in there right place.

Leif in Sweden

[CYCLONE 1952]

WHILST THAT OIL PUMP LOOKS SIMILAR THE 1957 364CUI HAS A VACUM PUMP ATTACHED TO THE BOTTOM AND IS DRIVEN BY A FLAT KEY FROM THE DRIVEN GEAR, THIS KEY HAS BEEN LEFT OUT AND THE VACUM LINE BLOCKED AS I HAVE FITTED AN ELECTRIC WIPER MOTOR,THIS IS A VERY COMMON CONVERSION. PRIOR TO THIS WORK THAT I HAVE RECENTLY DONE THE ENGINE HAS NEVER BEEN APART IT HAS BEEN AN ORIGONAL ONE OWNER VEHICLE,AS I SAID EARLIER THE RELIEF SPRING IS OPERATING AT THE RIGHT PRESSURE SO IT IS A COMPLETE MYSTERY WHY THE OIL PRESSURE IS BUILDING UP TO THIS EXCESSIVE LEVEL .BACK TO MORE TESTING

THANK YOU FOR YOUR HELP

[Guest Bob Call]

If the spring is opening at 40 PSI and you have tried without a filter element, there has to be blockage somewhere that is impeding the oil flow as some point and causing the pressure buildup.

[Bhigdog]

Not trying to argue here but if the relief valve is functioning and not letting the pump produce more than 40# pressure by bypassing flow I don't see how a pressure of more than 40# could be produced by anything else in the engine. A blockage might REDUCE flow but could not INCREASE pressure. THat only would occur under a constant quantity flow situation. Again not being argumentitive here just expressing thoughts.......Bob

[CYCLONE 1952]

well things have progressed and by the way i agree whole heartly with bhigdog, but firstly i origonally tested the relif valve with air since then i removed the pump again i have set up an old oilpan and mounted the pump at the same level as in the car. i fitted a pressure guage and a stop valve and i put an electric drill on the shaft and spun it at 2600 rpm and closed the valve to offer some resistance to the pump and it made 85 psi, would have gone higher if the drill could maitain the rpm (750 watt makita). so while the drill was running i had a friend loosen the cap that retains the spring beyond half it's thread and the relif valve eventually let go at 80 psi with the pressure side completly closed , i will have to source a new ball and spring some where (USA),i have tried some other springs from other oil pumps at a local salvage yard that now maintain 55psi with the pressure side completly closed so problem solved I THANK ALL THAT HAVE HELPED AND THOSE THAT HAVE LOOKED ON WITH SHALL WE SAY INTREST CHEERS

[Bhigdog]

Good trouble shooting! BTW, Kanter will sell you a rebuilt complete pump. Kinda pricey though at $131 (exchange)....Bob