2nd engine in a row with no oil pressure. Help needed
So I get another lq4 block and crank. I re use my old piston and rods and that's it. I'm also re using my f body oil pan and pick up and heads. Different oil pumps.
First motor didn't have a pressure gauge on it.
This new motor, on the stand with the plugs out, I can't get to build pressure. It pushes oil up to stock pressure port on the valley pan but does not create any measurable pressure. Confirmed with 3 guages. Also no oil getting to the heads.
Whatever killed my first motor has obviously been transferred to this motor.
So things that I took from the first lq
Heads
Cam
Piston and rods
Oil pan and pick up
Things that are new to this engine
Block
Crank
Oil pump
Covers
Pick up looks crack free. I had it sonic cleaned.
Any tips, suggestions anything, them out there.
Last edited by 64post; Sep 19, 2015 at 06:45 PM.
Even if was air bound, wouldn't it bleed itself pretty quickly after start up? I still haven found a reason why my first motor died and now I have this second on track for the same fate
With this engine, how are you trying to build pressure?
definitely still a suspect, but even pushing the clutch in, it made no change in idle speed.
This engine is on a stand, plugs out, no manifolds, full of oil.
So ive taken the allen port off the side of the block and tried squeezing oil into the block. It will take some but it gets to a certian point and just stops taking oil.
Ive pulled the pan and checked and even changed the oring on the pick up.
I even went as far as packing the oil pump full of vasoline. After that is actaully when it started getting oil to the valley pan port.
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But more of me wants to see some kind of measurable pressure before i kill another engine.
Such a stupid problem to have. So frustrating.
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Dumb question, but you've got the barbell in place under the rear cover right? That'll do low pressure. Also, what are your main bearing clearances? This is the one time a distributor was nice. Use a drill to spin the oil pump. No guess work. I've never had the starter trick let me down, but that's a grand total of three motors.
i never checked the main bearing clearences because the bearings were orginal to the block/crank and they looked pretty
I hope it's something minor for you. The barbell would be a good place to look. Not exactly easy though.
Kinda like an engine sitting around for a while and all the oil comes off and drips back into the pan, there's still enough oil on the surfaces to protect them until it is replaced with new oil.
As long as you did everything right (no leaks, barbell in place etc), douse whatever you can with oil and run it!
EDIT - I can build a little pressure just cranking the engine, maybe 15 20psi. But this is an engine that has been running as is primed.
The barbell and "freeze" plug are in place on this motor and the last motor.
I have not checked the oil pan to pick up clearence. It's all factory stuff, should I anyways?
So I know the engine is moving oil because it comes out of the stock sending unit port, but it doesn't make any measurable pressure.
If I didn't just cook a block from low oil pressure, I would just start the engine.
definitely still a suspect, but even pushing the clutch in, it made no change in idle speed.
This engine is on a stand, plugs out, no manifolds, full of oil.
So ive taken the allen port off the side of the block and tried squeezing oil into the block. It will take some but it gets to a certian point and just stops taking oil.
Ive pulled the pan and checked and even changed the oring on the pick up.
I even went as far as packing the oil pump full of vasoline. After that is actaully when it started getting oil to the valley pan port.
Could you be more specific about how you're trying to get oil pressure on a stand? I don't understand what you mean by "squeezing oil".
Who is doing assembly? How are you setting the thrust bearing?
Kinda like an engine sitting around for a while and all the oil comes off and drips back into the pan, there's still enough oil on the surfaces to protect them until it is replaced with new oil.
As long as you did everything right (no leaks, barbell in place etc), douse whatever you can with oil and run it!
EDIT - I can build a little pressure just cranking the engine, maybe 15 20psi. But this is an engine that has been running as is primed.
I do use different lubricants on the friction surfaces (pushrod tips, valve tips, etc) so that they do not start up dry. If you put pushrods and rockers on dry, then a oil prime would be a good idea.
Good thing you're using the "spin on stand" method to confirm proper oil pressure before installing this engine. Of course, keep doing this until this mystery is solved.
Please confirm that you did NOT pack the oil pump with grease or Vaseline or some other stuff.
What oil filter are you using?
You need to figure out where the oil flow is finding an easier path to flow to instead of pressurizing the oil galleys.
Is the oil pump body flat square and flush up against the block where it sends oil into the left side main galley?
How does the oil pan gasket and oil pan line up with the in & out ports to the filter boss in the oil pan?
Have a close look at this oil pan. You may have inadvertently transferred the cause of the problem from the first engine to the second engine.
The squeezing of oil was literally taking a bottle of engine oil, with a barb fitting going to the side port on the block and physically squeezing the bottle like you would with diff. It's an air tight seal and it would initially squeeze some oil into the engine and then come to a point where it stopped taking oil, no matter the pressure put on the bottle.
Paul-
Unfortunately I did use Vaseline in the pump. I wish I didn't but I did.
As of now I'm using a purolator filter
The pump is sealing. I had the front cover off while trying to prime the system and could not see any oil bleeding from anything in the front.
Oil pan gasket lines up good with the 2 ports. I have a gauge drilled and tapped on the cover right there along with another mechanical fuel pressure gauge at the valley pan port.
Today I fabbed up a pressure oiler. The motor took 8qts rather quickly, still didn't make any pressure and still no oil up top. This, in my mind, confirms there's a real issue. Something is bleeding my oil pressure off. Pan is coming off again right now and I'm checking the pressure relief valve in the pump, possibly swapping it out with a used ls1 pump for diag.
Still hasn't been able to creat its own pressure but with the air pressure oiler we are seeing oil pressure.
Just got the last lifter to bleed but still can create its own pressure









