1964 Oil Pressure Gauge issues

[Maxx_basher]

good afternoon,

i have a 1964 standard 390, 600 holley and pertronics ingnition. my oil pressure gauge seems to start at just above 3/4 and after running a while goes to high. hoping for some advice on how to isolate the issue. not sure where to start.

thank you in advance

 

[74 Harley]

Oil pressure sensor is probably going bad.

 

[Hernando Muñoz]

good afternoon,

i have a 1964 standard 390, 600 holley and pertronics ingnition. my oil pressure gauge seems to start at just above 3/4 and after running a while goes to high. hoping for some advice on how to isolate the issue. not sure where to start.

thank you in advance

Check your oil pump for a stuck bypass valve and spring. When the pump rotates, baing a positive displacement pump, the pressure can go up to a point where something else explodes, typically the oil filter. So they do have a pressure releif valve to bypass the oil to the pump suction, all inside the pump, which is a sliding plunger conyrolled by a spring.
If it gets stuck closed or semiclosed, your oil pressure will raise to incredible levels.
You must find this valve and clean it all well and lubricate with assenbly oil before reassemble. Check for wear on the plunger...it may need to be replaced.

 

[74 Harley]

To really check what is going on you need to remove the sensor, connect an actual gauge to the engine and start it. Check your pressure real time.

 

[Maxx_basher]

To really check what is going on you need to remove the sensor, connect an actual gauge to the engine and start it. Check your pressure real time.

is the oil pressure relief valve external on the block or is it in the oil pump its self in the sump

 

[74 Harley]

The oil pump itself. In all my years of owning and working on these cars I have never seen that as an issue. Not saying it couldn't happen, but not common.

 

[Maxx_basher]

Thank you all again for your help. i am getting an oil pressure tester and a new sender ready as the old one needs to come off to test and i will soon find out. fingers crossed thats what it is as the oil pump seems like a big job lying on my back. thanks again