New Motor, No Oil Pressure

[Doug Wil]

OK, rebuilt many a motor but never a flathead.
Total rebuild including new oil pump gears installed to specs.
Also installed a WIX spin on, plumbed the right way.

I tried to preprime the pump by pouring oil into the uptake tube, but I imagine it wasn't too effective once the motor was rotated upright.

Anyways, fired it up and watched the oil pressure gauge and shut it off after about 30-40 seconds, took the oil gauge line off, and no oil.
Took off the spin on filter and no oil.

So the pump isn't putting out or getting any oil up to the tee fitting at the rear of the block.

Anyway to prime this pump or other ideas?

Thanks Doug

 

[Bruce (VA)]

" I tried to preprime the pump by pouring oil into the uptake tube"

Most folks put grease or assembly lube in the pump. To late for that now.

Remove the 15/16 hex nut to the right of the water pump. This is where your oil gallery is for the valves/lifters is. Don't lose the little spring under the nut. Use an oil squirt can to put about a cup of 90w oil in here. Replace the spring & nut.

If the orifices in that spin on filter are too big you will lose oil pressure.

75 Tips

 

[Doug Wil]

OK, I have read some of the posts on the subject and refreshed my memory, this has been about a 9 month project.

Anyway I did prime down the oil relief plug with 30 wt when I assembled it.

And just now I did so again, got oil at the gauge line, hooked up the gauge but no pressure.
Removed the gauge and no more oil flow.

Primed for a 3rd time, and again got oil flow at the gauge fitting, hooked up the gauge, no pressure and appear to have lost the prime again.

 

[Doug Wil]

Bruce, do you mean 90wt gear oil?

 

[Den N Ms]

Doug,remove the line from the back of the pressure gauge and prime the line through the brass fitting with a pump oil can and a piece of vacuum hose hooked to the line and oil can.Pump a can full or two and try it again.

 

[Bruce (VA)]

Yes

 

[Doug Wil]

OK, did that and it worked!
Took a lot of cranking w/o plugs to fill that filter.
Tried prefilling it and I guess you can't??

Anyway ran it for about 15 minutes and the pressure ranged from 10 at cold idle to 20 at cold rpms.
Warmed up it dropped to 5 and 15.

Decided to try another gauge, it read 0.
Put the original gauge back on it it too now read 0.

Disconnected the line and no oil flow.

Why am I losing prime all the time?

 

[Royse]

Those oil pressure numbers aren't too impressive for a new engine.
Is your pickup tube solid? No movement or air leaks?

 

[Doug Wil]

Unfortunately I won't know till I tear it apart, again.

Ugh.

 

[Royse]

You can feel a loose pickup tube through the oil drain
hole. Once you take the bung out. Doesn't help with
a leaky tube and still means draining the oil.

 

[Doug Wil]

Well it definitely isn't loose, I had to bend it slightly when I installed the pan to aline the drain plug screen.

Rather than work on it outside in the dirt, I will probably pull the motor and bring it in the shop.
Kinda worried about the bearings running with no or intermittent oil flow even though everything was well greased with assembly lube.
So I might as well take a look while the pan is off.

This has been a very frustrating project. I bought a complete but tired side dist engine to replace my front dist model.
Many of the hard parts were broken or bubbarized, and it seems many of the new replacements didn't fit right without work or at all.

Everything poked along waiting for my next parts order, or a needed tap or bolt and the 120 mile trip to the closest competent machine shop didn't help matters.

Really not looking forward to going back in there.

 

[Tall T]

My Jube pickup tube has some wiggle (thru the drain hole) but I have a steady 45 to 50 psi and after three seconds it shot up after the oil change to 15W40.
I'll take the pan off to see what gives when the tractor can be moved down to my shop door.

I'm wondering if the tube is contiguous right through that screen surround part or if there is a joint in the tube where it meets the screen surround part. If there is a joint or a break where it meets the can, then the two-bolt connection at the pump flange must still be tight if I have such good pressure.

I can't remember exactly if the distinct wiggle I felt was the screen surround or the tube. The screen surround is probably soldered to the tube and maybe that is what is loose in mine.

T

 

[Hobo,NC]

You can confirm operation of the suction side of the pump right were its at no need to drop the pan...

 

[Doug Wil]

How do I do that?

Thanks

 

[Hobo,NC]

It can not pump what it can not pull into the pump (suck up),,, its not a gravity flow system,,,, it has to pull in what it pumps (suck up) the best indicator of a healthy pump is how efficient the suction side works,,, its forgotten and very misunderstood,,, should be on the guru test

while you have gone this far,,, add a piece of clear hose to the center of the pick up tube,,,, drop the other end in a bucket of oil,,, crank the engine over,,, what do you see,,, I think 1/2" I.D. hose will work...

It should suck on the starter along no need to fire the engine..
You can you your finger to check for suction and go as far as to use a vacuum gauge..
It should suck as soon as you turn the pump...


This is the first info I would want to know to plot my next move...

TOH ( TheOldHokie ) also has some good oil pump testing info....

 

[Charner MS]

The way I prime a stuborn oil pump is, remove plugs, inject a few spurts of oil. Have someone pull you in 3rd or 4th gear a 100 yds or so. If it's a priming problem only, this is a sure cure.

 

[Hobo,NC]

He got it primed he now suffers from low OP on a rebuilt engine...
He now needs to find why he has low OP...

 

[NNP]

do Hobo's test to see if the pump is working.
Then, this statement...

"Well it definitely isn't loose, I had to bend it slightly when I installed the pan to aline the drain plug screen. "

If it was already weak, this might have cracked the intake pipe joint up at the top.


edit: Hobo's test is handy for other things too.
Flushing watered oil out of passages so it doesn't contaminate new oil, pan on or off.
bucket of clean oil, hose, plugs out, spin a rear in high gear.
makes a mess, but effective.