VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 1952 235 Oil Pressure/60 lb. Gauge

What should the oil pressure be at idle and with some acceleration on a 1952 235? Should it be similar to that of a 216? I'm working on a 1951 Suburban in which a 1952 235 had been installed by a previous owner. The old gauge cluster was pretty well corroded and rusted out, so I purchased a new cluster from a re-builder some time ago. Unfortunately, at the time of the purchase, I didn't notice that the restored gauge cluster was for a later truck--the oil gauge reads up to 60 lbs. When I hooked up a new oil pressure line and started the engine, I got NO reading from the 60 lb. oil gauge. I disconnected the line and hooked it up to the oil port on the old gauge, which reads at a maximum of 30 lbs. When hooked up to the old gauge and I started the engine, the needle moved to about the middle point on the oil gauge, i.e., which should be about 15 lbs. on the gauge (though the face of the old gauge is faded and rusty and hard to read). My point is that when the old gauge is hooked up, it does move and register at about the half-way point (between 0 and 30), and when I turn off the engine, it moves slowly back to 0. On the other hand, when the new 60 lb. gauge is hooked up, I get no movement at all. Is this due to the fact that the new gauge is calibrated for full-pressure oiling and this vintage 235 doesn't put out that much pressure? Is about 15 lbs. as registering on the old gauge sufficient for this vintage 235 (I know that's a suitable reading for a 216)?

Finally, I don't suppose there is any fix for the new oil gauge beyond acquiring a 30 lb. gauge, tearing into the new cluster, and replacing the 60 lb. gauge with the 30 lb.? The prospect of crawling in under that dash again to disconnect all the wires and connections is a terrible one--putting it altogether and installing it was a big enough nightmare?!?!?

Thanks in advance for your thoughts.

Jim

The oil pressure depends on temperature and viscosity of oil. Most of us use 10W-30. As long as the pressure at hot idle is positive enough to lubricate the valve train and registers on the gauge it is okay.

Interesting situation. Both of the gauges measure static oil pressure. Flow is not a factor in that.

I would have to question if the 60 psi gauge is working properly. It should register the same 15 psi as the 30 psi gauge.

One step I would try would be to “bleed” the line where it is connected to the 60 psi gauge. Normally trapped air is not an issue. The air compresses and eventually will transmit the static pressure. I would at least ry it.

With respect to the registered oil pressure 15 psi seems low for a full pressure engine at driving speed. It would be ok if that is the pressure at idle when hot.

I agree with Rusty and question whether your 60 lb gauge is working at all.

But... if the engine is a 1952 235... it should be a low pressure "pressure stream" engine in which case 15 lbs at start up and at slow idle is reasonable.
Once the oil is hot, it should still run 7 or 8 lbs idling, but if it's a little lower I wouldn't worry too much over it, as long as oil is getting up too the top end as Chipper says.

Yes.


Me too. It sure sounds like it isn't. It should have at least moved. It really should be replaced with the right gauge, as the 60 psi gauge wouldn't indicate much even if it worked.

There is something wrong with the 60 pound gauge...period.

Thanks to all for the quick and helpful replies. When the old (original?) oil line was on and the gauge didn't register, I replaced the line with a new line; still didn't register. That's when I started experimenting with the old gauge, etc. My first impulse was to think (as all of you above have surmised) that the 60 lb. gauge was defective--but I was hoping against hope that there might be another easy fix/answer. Looks like I will need to replace that gauge (my ever-aging body will need to get its contortionist act together!). I think I have some other low pressure oil gauges in my spare parts bins--if so, I'll check one more time to see how the pressure registers, but it certainly looks like removing the gauge cluster and replacing the oil gauge is in my near future.

Thanks again.

Jim

Confirmed--it's definitely the gauge. I just hooked up two separate gauges that I had here, one from a 37/38 pickup and another from a 38 coupe--both registered about 12-15 lbs. at idle and when accelerating a bit, rose up to over 20 lbs. of pressure. So, it appears that the engine itself has what would be fairly normal pressure for a low-pressure 235. The gauge is obviously defective.

Thanks again for your help.

Jim

Thanks for the follow-up posts. I am glad that you were able to diagnose the problem.

For some reason this feeble mind cannot keep straight what type oiling system was on the early 50’s 235’s.

The first one with full pressure oiling was the 1953 Powerglide (only) engine. All got it in 1954.

The point that confuses me is that the early 50’s 235’s were splash lubricated but had hydraulic lifters.

I had never considered that point until just now. They do have an oil pump, and that array of squirt guns in the oil pan. I guess it's enough oil pressure? It sure isn't much.

On a 216 or dipper 235 engine the main bearings are the only thing that gets the full pressure from the oil pump. The oil pan troughs and rocker arms get their oil from the low pressure side of the oil distributor valve.

Seems to me that the valve train receives oil owing to gravity feed only. There is no pressure owing to the open line going over the loop and no closed system in distribution of the oil from that point on.. Is that about right?

I had shoulder surgery on July 15 this year. Start physical therapy this week. It is proving a real trial not being able to use my right arm much and not being able to drive for the first time for 71 years. That sucks. Does too!

To pass on some advice: As we get older we must look after ourselves with more and more care. I messed up my shoulder back in late spring by ignoring the instant advice and doing something I shouldn't. Falling ain't no stinkin fun.

Best,

Charlie

The pressure is IN THE LINE GOING UP TO THE VALVE TRAIN.

Readings of 15 to 20 lbs at idle are not usual for the low pressure motor, as far as I understand. Something doesn't add up here.

For a 1040-1953 low pressure oilimg engine hot idle pressuer is abut 5 to 7 ponuns with about 15 pounds at highway speed. 1937-1939 would be a bit lower.
The, reading i is taken from the main oil gallery that feeds the main bearings. If you were to take pressure readings from the low pressure oints it would probably be only a coupe of pounds at highway speed.

Fo a full pressure oiling engine the pressure is about twice that but some of the pressure at the main bearings is bled off to the connecting rods. To reduce pressure to the rocker arms the flow is metered by restriction.