Zero oil pressure

Hi, there! Spent a few hours on the forum and otherwise on the Net to figure out what to do, have done a few things adviced, but problem persists: zero oil pressure. So now I turn to all the expertise on the forum to ask for help...

Here's the story: 1966 Austin Healey 3000 MkIII owned by me for the last twelve years. Has always had relatively low oil pressure (but according to posts in this forum, still adequate). Last driven October last year with no problems. Woke the car from its winter hibernation and took it for a spin last week and soon noticed that the oil pressure needle was jumping between zero and 40. Immediately returned home, obviously. Since then I have replaced the oil pressure valve and spring, installed spin-on filter and changed oil to 20-50 viscosity. Unplugged the coil and when cranking the engine, I now only get zero pressure, needle staying put. Checked to see if the filter was installed the wrong way, but I guess not, because the new filter was now filled with new oil. Unscrewed the pipe to the oil pressure gauge and turned the engine again to see if any oil came out, but it didn't. Checked to see if needle was stuck, but it wasn't. Unscrewed the othe end of the same pipe (on the engine side) and still no oil came out of the engine.

Have read that I could remove the rocker cover to look for proof that oil is flowing, but as far as I understand, this should be done with warm engine and I'm afraid of running the engine for that long without being sure that is sufficiently lubricated.

So, here I am, concerned that there might be a serious problem, but cannot understand that this problem has occured "over night" even if "night" here refers to a couple of months.

Any help, suggestions and advice is highly appreciated!

The only thing I can think of is the gears on the distributor/oil pump drive shaft got stripped. That might explain the erratic behavior before total loss. Be sure to confirm with a known good gauge--though no oil coming out of the gauge feed line is a bad sign.

your going to have to drop the pan and see if the pump is cloged

Thank you for replies! I just now removed the oil filter, turned the engine and oil immediately gushed out of the hole. Doesn't that indicate that the oil pump works as it should, afterall?

You have installed the spin on oil filter kit incorrectly .

KarlHB said:

Thank you for replies! I just now removed the oil filter, turned the engine and oil immediately gushed out of the hole. Doesn't that indicate that the oil pump works as it should, afterall?

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Yep : Put the original filter back on an see if all is well again.

Hmm... The thing is that it wasn't well before I installed the spin on filter kit; I had zero pressure then and was hoping that installing the new filter and replacing the pressure valve would correct the issue, which it didn't. Also I don't understand that I could have installed the spin on filter kit incorrectly when the new filter after installation has been filled with oil and I can see that oil is coming through (which must state that I haven't installed it the wrong way and/or blocked the holes with the gasket - or am I completely wrong here?).

Hi Karl,

As far as I am aware, no oil pressure is somewhat dramatic and even with excessive leaking from the valve train and/or timing chain tensioner, I would expect there to be some pressure registered in the system. However, if no pressure reading is present after a number of turns, and with all you have already done, I would agree with others and look to a failure relative to the pump. I would pull the crank case and see if the screen and pickup is in good order before pulling the pump to evaluate internals and drive gear.

Moving oil with no backpressure resistance is no test for the functioning of the pump. Even a fractured gear could have sufficient friction to move some but may begin to slip when even a small amount of pressure resistance is encountered.

Good luck,
Ray (64BJ8P1)

One other possibility (although admittedly unlikely): check the flexible hose from the oil sender to the gauge. If it's broken, I think you see all the oil spraying out, but it might be clogged or otherwise compromised.

Try a substitute gauge while turning the engine over with the coil disconnected.

Alright - dropped the pan and found the screen to be clean which obviously wouldn't obstruct the oil flow in any way. Will the next step for an instant amateur car surgeon be to inspect/change the oil pump, or is there anything else I should try before that? And if I have to change the pump; is that a straight forward task?

Keith_M; Have checked the hose, which isn't broken, but I haven't tested to see if it is clogged because I figured that there was a problem "ahead" of the hose when no oil came out of the engine when the hose was removed.

Karl,

I appreciate your level of concern and frustration in not finding any definitive indications of the source of the issue and not wanting to proceed too deeply into dismantling the engine in the search. The screen may have been clear but how was the tube drawing the oil to the pump? Check for cracks or any other anomalies that could kill the pump’s intake draw.

Hang in there and think of the story you will have to tell at your next Healey gathering.
Good luck,
Ray (64BJ8P1)

Thanks for all the input. Made up my mind to change the oil pump, which probably isn't a bad idea, anyway, and hopefully that will rectify the problem. Order is placed, so now it's waiting time. Good thing the weather forecast isn't too good

Have you tested the gauge separately?

dwalpole said:

Have you tested the gauge separately?

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No, I haven't, because I concluded that wasn't the problem since no oil came out of the engine when I disconnected the tube feeding the oil pressure gauge.

Have you checked your spin on adapter is on correctly? I had a similar problem a few years ago and went through all the things you are going through now.
the adapter was marked up and installed accordingly, I took it off and installed the opposite way both holes lined up again, put the oil filter back on and everything was fine.
Apparently the spin on oil filters have a one way valve in them. They are designed so the oil flows in one direction only. Even though you filled the oil filter with oil, you would be pumping oil in the wrong direction, against the valve, it would prevent it from flowing oil through the motor. If all else fails I would suggest checking that.
Originally, when you drained the oil out, was there a chance you did not have enough oil which could have caused a problem?
Or because the engine sat over the winter months and the tube running from the gauge back into the engine may have emptied the tube going to the gauge and caused an air pocket on restart up between the gauge and the oil feed causing the gauge to be unpredictable.
I hope this helps,
Marty

Frameman said:

Have you checked your spin on adapter is on correctly? I had a similar problem a few years ago and went through all the things you are going through now.
the adapter was marked up and installed accordingly, I took it off and installed the opposite way both holes lined up again, put the oil filter back on and everything was fine.
Apparently the spin on oil filters have a one way valve in them. They are designed so the oil flows in one direction only. Even though you filled the oil filter with oil, you would be pumping oil in the wrong direction, against the valve, it would prevent it from flowing oil through the motor. If all else fails I would suggest checking that.
Originally, when you drained the oil out, was there a chance you did not have enough oil which could have caused a problem?
Or because the engine sat over the winter months and the tube running from the gauge back into the engine may have emptied the tube going to the gauge and caused an air pocket on restart up between the gauge and the oil feed causing the gauge to be unpredictable.
I hope this helps,
Marty

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Thanks, Marty - that does seem to be a plausible explanation. I was certain that because the oil filter was filled with oil and also because oil came out through the middle hole on the adapter when the engine was turned, that everything was ok there. I'll go through everything again when I change the oil pump, which might improve my initial low oil pressure, anyway.

I believe there is a restrictor between the engine block and the oil pressure flexible hose. You might want to check before going any further as the restrictor hole is fairly small and a blockage will give you no oil pressure reading. I have seen these blocked before and all it takes is to remedy is to remove the adaptor / restrictor from the engine block and blow it out with compressed air from the hose side. I'm sure my Healey has a restrictor. The idea is that it act as a dampener for the gauge but also will restrict oil loss if a break occurs between the restrictor and the gauge. The restrictor is discussed here https://www.mossmotors.com/forum/forums/thread/25949.aspx

Paul

Weekend and time on my hands to have another go. Moss didn't have the oil pump in stock so I checked the restrictor between the engine and the oil hose: clean and clear. Hose: ok. Uninstalled and installed the spin on adapter/filter again: ok. Checked the pipe drawing the oil to the pump: seemed ok to me.

Decided to put the pan back on, filled oil back on the engine and tried to crank the engine again: zero pressure. Bought a new type oil pressure gauge and tried it: zero pressure, BUT I noticed that the nut isn't set firmly to the oil pipe (only to the gauge), and seems to be 'loose'. Would that allow pressure not to build up? Still no oil coming out of the pipe, though, not even when I tried to crank the engine before I attached the new gauge.

Is changing the oil pump now my next option?

KarlHB said:

Weekend and time on my hands to have another go. Moss didn't have the oil pump in stock so I checked the restrictor between the engine and the oil hose: clean and clear. Hose: ok. Uninstalled and installed the spin on adapter/filter again: ok. Checked the pipe drawing the oil to the pump: seemed ok to me.

Decided to put the pan back on, filled oil back on the engine and tried to crank the engine again: zero pressure. Bought a new type oil pressure gauge and tried it: zero pressure, BUT I noticed that the nut isn't set firmly to the oil pipe (only to the gauge), and seems to be 'loose'. Would that allow pressure not to build up? Still no oil coming out of the pipe, though, not even when I tried to crank the engine before I attached the new gauge.

Is changing the oil pump now my next option?

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I think if the nut was loose you'd have oil dripping. Are you double sure the gasket is installed correct on the spin-on oil filter to block location? Is there any oil in the filter?