Hi folks, my oil pressure on my 62 Etype is around 20-25 pounds at idle. I checked the oil level and checked the oil filter and even when I rev it up to 2000 rpm, all it gets is maybe 35 pounds of pressure.
I did research and found I should check the oil pressure relief valve and make sure the spring isn’t worn. How can I tell if it is worn? Should it be a certain length?
I also saw I should squeeze or clamp shut the rubber hose coming from the oil pressure relief valve and if I squeeze it and the oil pressure increases, then it is a worn spring? Is this correct?
I also saw where it might be the sender unit fastened to the top of the oil filter assembly unit. Is there anyway of determining if this is the root cause, short of replacing it?
Jan, first and foremost before doing any troubleshooting it is important to understand what the oil pressure actually is, not what your gauge says. They are notoriously inaccurate. Pull off the sender and screw in a manual gauge and see what the real readings are.
I’d also contend that if the numbers you are seeing are actually accurate, that isn’t too bad and nothing to be very concerned about.
This could be normal for a worn engine.
If it were my engine, I would want to know the real pressure is and I would temporarily plumb in a manual gauge where the oil filter is.
If the oil pressure is higher than displayed on your dash dial, the likeliest cause is the sender. So I would replace the sender.
If that did not solve it I would look at the relief valve, which I think can be taken apart in earlier models.
If that does not solve it, you can calibrate your sender and gauge with a compressed air setup or you can leave all alone and just know that you have decent pressure but it is not reading so!
Indeed. Presuming Jan’s readings are for a warmed up engine, this is normal. I have a '62 as well. The competition handbook is the only place I recall seeing a reference to oil pressure performance. In effect those intending to race a 3.8L car should be looking for 40psi at 3000rpm as an operating pressure. Paul.
I just bought the car last fall and the oil looks fresh and I am uncertain what brand. As soon as a get a new oil filter and seals, I will change the oil and Castrol is a good brand. Thanks, Jan
Jeffrey and Wingnut, thanks for the feedback. I have ordered a mechanical oil gage that I will install in a T fitting so I can run both the electronic and the mechanical gage to see if both are reading the same. I am also replacing the old oil and filter with fresh Castro 20-50 and a new filter to see if that will make a difference. Also, I am replacing the oil relief valve spring to be sure that is not worn… I have grounded the oil sender unit wire and sure enough the gage pegged to 60 psi so that tells me the sender and the gage are working OK.
On a different subject, I tested the compression and got alarmingly low readings. I will post something for all to comment.
Jan
Compression should be done with throttles held open so cylinders can take in air/fuel without restriction … just in case you did not have them open
Grounding the sender will give you a false reading. The sender unit comprises a bi-metallic strip with contacts that open and close, the frequency of which determine the amount of guage deflection. Shorting it out will just establish that there is electrical continuity ( and likely burn it out if connected too long) Following the other suggestions is the prudent course, IMO.
Hi everyone, thought I would update you all on my findings with my low oil pressure. So I have a 1962 Etype and at 1500 RPM the max oil pressure shown on my gage is 30 psi. I did pretty much everything all of you suggested. I changed the oil with Castro 20-50 oil, changed the oil filter, changed out the oil pressure relief valve spring, and I added a ‘T’ fitting into the oil output above the oil filter and installed a mechanical oil pressure gage into the T. I fired up the engine and at 1500 RPM my gage still read only 30 psi BUT the mechanical gage read 48 psi…!! I like that much better. I will assume I have a faulty oil pressure gage. I can swap out the gage but I think I will leave it now that I know I have great oil pressure.
I am now moving onto the compression readings. If you recall, I only had 70-75 pounds of pressure in each cylinder. I think it was a faulty pressure gage tester I borrowed from O’Reilleys Auto. I will check it again now that I know I have good oil pressure.
Jan, check with the engine warm, battery charged, spark plugs out and throttle wide open.
Even values between cylinders (+/- 15%) are more important than high figures. If it runs well I wouldn’t worry though.
And it’s most likely your sender.
David