The Stovebolt Site Forums The Shop Area Engine Shop Fresh build no oil pressure?

I finally got the engine to the point of running after a fresh build and I have no oil pressure. About the only thing that I did internal was bore the cylinders and install different pistons. All the bearings looked great and measured out like they should have. The oil pump at first assembly did not turn until I installed two paper gaskets.

I am guessing I have an issue with the pick up tube not being sealed and it is sucking air. Or maybe I did not tighten one of the pressure lines although I pulled the oil pan back off while it was on the stand to make sure they were tight....

I'm going to pull the distributor and turn the oil pump with a drill to make sure I don't have an issue there, but I'm sure I'll have to pull the pan...

Any one have any other thoughts?

For sure spin the pump for a test.
It is always a good idea to pump up pressure first on any rebuild.

When you had it hot tanked or cleaned did they remove the oil galley plugs?

It sounds like you ran the motor but didn't see pressure on the gauge... so the first question is did *any* oil make it to the rockers?? If not then time to take things apart. If yes, then your gauge lines/gauge might be bad.

You're supposed to have one or two thou play, set with paper gaskets, from the gears to the cover.

Did you check to make sure the pressure relief valve in the pump worked smoothly after assembly?

If it is a low pressure engine, did you check the oil bypass valve (triangular plate behind the heat riser? a broken spring will let it lay open.

I ran the engine for 5 seconds and didn't see any pressure. I pulled the oil line off going to the gauge and crank over with out starting and no oil...

I did check that the bypass valve moved freely after assembly.

The bypass valve did not have any broken springs.

This engine had been running just fine before taking it apart. It is still a lower pressure engine. The machine shop did remove oil galley plugs to do machine work and it appeared they had been replaced, but I guess it is time to start checking those out as well!

are you sure you got the distributor back in correctly?, you can get it in far enough to engage the gears, and will run, but it isn't in far enough to engage the oil pump

Pulling the distributor will be the first thing I try. Am I sure? Well, I was until I saw the oil gauge!

And yes, it is sitting flat on the block and the bolt is in and tight.

I'd pull the distributor out and make an oil pump drive to use with a drill and see if I could get any oil moving through the engine. I no oil seems to be getting picked up by the pump I would consider over filling the oil pan with oil and trying again to rule out a loose fitting or some other issue with the plumbing for the pump.

the collar on the distributor, can move up and down on the distributor. It can be bolted down flat, but not be in the right spot.

I had the same thing happen to me.The collar on the distributor wasn't allowing it to seat all the down,resulting in no oil pressure.It had oil pressure while i was priming the system.

Tim

Easy way to check that would be to put some grease on the tab at the end of the dist, insert dist all the way, take it back out. Look at the grease on the tab... it should look like it mated with something/be squished out a bit.

I have done this. Put the vacuum advance on and all the way up the dizzy as you can. Put the dizzy in the block and you can "feel" it engage the oil pump. Then loosen the screw and set the vacuum advance down to the block. It will go about a 1/2 inch down from the shoulder. Next time if you are not engaged it will set above the block and you will know it is not engaged with the pump. It can be a bit fussy to get it right. After a while you will wonder what all the fuss was. pfarbers' trick is as good as I have seen. Think of this as a skill, like reading a micrometer. You gotta have it and you gotta feel it.

Make sure the oil pick-up tube assembly is still firmly affixed to the oil pump & laying horizontal & close to the bottom of the pan.

I would loosen the collar on the distributor and make sure it's all the way down,then tighten the collar and bolt down.I had oil pressure when I primed the pump and oil system. When I fired the engine,I had no oil pressure,shut it down immediately.It took me a little bit of investigating to figure out the distributor wasn't all the way in place.



Tim

Wow, Thank you to you guys. I would not have checked that first, but that was it.

Now, I wouldn't have checked that first because I didn't do anything to the distributor while the engine was apart other than clean it. For the reason that I didn't want that to be a variable in me making it run again. I was wrong. I would have pulled the pan off and scratched my head.

Thanks again, now I just need the temps to come up a little bit to go drive this...Oh and the foot of snow to leave!

Glad we could help you !!!!!

Good day in the shop. You fixed something. Enjoy!

Let us know how it goes.

Hey Don,

If I do this with the distributor out of the engine and use a drill and old screwdriver shaft, should I not see oil being distributed out to the rocker arm assembly from the bent oil distribution tube in the center of the rocker arm?

John

Yes, you should see oil being distributed there and all through the oil tube that runs front to back including at each rocker. If you don't see oil freely moving through, there is something clogged or wrong somewhere. No need to try to start the engine as that would do more damage. The drill test is a really great test since it completely emulates how the oil pump would work during normal operation. The drill may do it better but not by that much.

I would also add that I never saw oil pressure on the gauge. I did pull the line off at the block and got oil out. I then checked the return tube at the rocker and I was getting oil there.

It took me a while to align the oil pump with the distributor, but once I felt it I knew it was in.

Hopefully I can drive it at the end of this week...