VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 1959 235 No oil pressure

I have a 1959 235 engine in my 46 pickup. I am not getting any oil pumped through the oil lines to the filter and no oil pressure.

Is there anything I can try before dropping the pan and pulling the oil pump?

Thanks, Mark

Do you know if there is oil going to the rocker arms?

Have you tried a different pressure gauge? You can connect any generic oil pressure gauge to that port on the engine.

Have you removed the lines to and from the oil filter and blown air through them?

I would be very cautious running the engine too long or under any load until you diagnose these conditions.

What is the history here? Is this the first start after a rebuild? Has the distributor been removed and reinstalled? It is possible to run the motor with a distributor that has not seated into the oil pump. I would suggest pulling the distributor and running the oil pump with a drill.

Did you check the dip stick ?

Possible the the distributor raised up a llttle and disengaged from the oil pump.That would be my first thought.

I agree with old216 to remove the distributor and run the oil pump with a drill. This will prove if the oil pump and gauge are working.

I recently ran into this situation with the '28 engine in Lurch. It's been five years since my engine rebuild and everything was working just fine until last week. I started it up for a drive and there was no oil pressure. ;-(

I went around the block once to see if it would come up but it did not.

I first checked the oil gauge by disconnecting the tube going to it and blowing a little compressed air into the back of the gauge. The gauge popped up so the gauge is good. So I reattached the input tube.

Then, I pulled the distributor out and ran the oil pump with a screwdriver shaft in a portable drill. The gauge now showed some oil pressure, so the pump is good.

The bottom pin of the distributor gear shows some wear like it was riding on top of the oil pump shaft. Also, the distributor gear has wear marks towards the bottom of the gear instead of the middle of the gear. This leads me to think that either I last installed the distributor incorrectly (it wasn't seated all the way down) or the distributor worked its way up and out of the oil pump shaft over time.

I have not put the distributor back in yet. I will do a complete write up when I finish and everything is working again.

Stay tuned. Dean

Like others have suggested check oil level then pull the distributor and drive the oil pump with the electric drill, if that doesnt produce oil drop the pan.
Tony

History on the engine, only a few starts since rebuild.
I have checked the oil and it is good level. I noticed a lack of oil on the rocker arms so have just started to research the problem. I am not getting any oil up through the line to the oil filter either.
The oil pressure gauge may be no good (or not) as it is the original and have not found one to replace it yet. I am not to worried about it showing pressure as long as I get oil up through the head/rockers. the distributor was pulled at rebuild and then reinstalled later.

I will try some air back through the oil line to the filter. Then will pull the distributor and try and pump with a drill/screwdriver bit to get oil through the system.

Thanks for all the insight.
Mark

Thanks for the details. The drill & screwdriver bit thing is a safe way to test the oil pump with minimum risk to the engine.

Let us know the results.

I used the air back through the oil line (that goes to the filter) and then the drill with a screwdriver bit to turn the oil pump. After a few minutes I was able to get oil to the rocker arms. Yeah

It must have been an air lock downstream from the pump.

Thanks so much for all your Help!

Mark

That is good news! Thanks for the update.

Normally the oil pumps on these engines are self priming and will push out any air. It is hard to explain what might have happened in your engine.

Take your time and make sure the distributor drive shaft is properly engaged with the cam gear and the oil pump drive is seated.

I suggest that when you get ready to start the engine keep the ignition off while you run the engine with the starter. Watch for the oil pressure gauge to move.

Now for a really crazy question. What changes were made to accommodate the higher oil pressure engine?

Turns out my problem was from the shaft not engaging the oil pump. I did not realize that the clamp on the dist. housing moved up and down, distributor shaft was about 1/2" too high to reach the pump slot. thanks for the guidance, several of you have pointed in this direction.

It is showing 25 to 28 # oil pressure now on the original gauge.

Rusty, I am not sure what changes are needed to accommodate the higher oil pressure engine?

Thanks again for all the help.
Where can I find tune up specifications for this engine. 1959 235
Bore 30 over, solid lifters, Howard cam M4f with 3/4 grind,


Mark

With hot oil you shold have 35 pounds at 40 MPH

My stock oil gauge pegs out at 30#, the stock gauges are 1946 chevy truck, so I may have to make a change in the gauge.
I haven't had it over 25 mph yet but it does peg the oil gauge.

Hi Mark

A stock oil gauge from a 1941-46 GMC will be identical to your original gauge with 2 exceptions.
The gauge will read from 0 to 60 psi instead of 0 to 30 psi.
The face of the gauge will be a lighter brown color.

GMC used an engine with full pressure oiling like the later Chevrolet 235's so they needed the higher pressure gauge.

And the GMC gauges sometimes show up on Ebay.

They can also sometimes be found NOS from people who sell old WWII military surplus.
You are looking for something like this:
https://autopartsobsolete.com/1940-...e-gauge-nos-1506373-1506067-1506068.html