Rebuilt Miata Engine, No Oil Pressure

In reply to Tyler H :

This is a stock pan on this engine. There is the appropriate amount of oil in it.

In reply to 02Pilot:

Doesn't matter if the gauge is working properly. Oil comes from the pump to the filter housing first, and there is no oil at the filter housing

In reply to rustybugkiller:

We are currently building on from pressure-rated PVC pipe, a schraeder valve, a ball valve, an old filter and some hose.

In reply to wvumtnbkr:

Yes, it has oil in it

There is a pressure relief valve.   Stuck open?

Would a stuck open pressure relief valve result in what sounds like no oil being pumped around the engine?

It might. 

We always pack the pump, so I can't say what the behavior is like without it. I would definitely pre-fill the filter (if this hasn't been tried) and just crank it with no plugs for 30 seconds to see what happens. 

So, made a prelube canister from some PVC pipe, with a shcraeder valve on one end and a ball valve on the other, then soldered the fitting into the top of a sacrificed oil filter. Charged it up to 40-50 psi and fired a quart of oil into the engine. During the process I did see oil pressure registering on the gauge. Tried cranking it with the plugs out afterwards and nothing. Thinking that maybe the rpm was too low for it to register, put the plugs in, installed the fuel pump relay and fired it up, and at 2000rpm (doesn't idle, have to feather throttle) no pressure at the gauge.

Time for motor surgery. 

dean1484 said:

Time for motor surgery. 

Yeah, just what I was afraid of.

Ugh.  I'm gutted for you.  That's heartbreaking to get that far along and have to go back and start over....

I hate it for you but glad you were paying attention on startup. It is very easy on an initial startup to be excited and miss it. Sucks but you done good!!!  

In reply to wae :

Yeah. Pretty devastated. First autocross is May 6th and I have to get the engine out, diagnosed, fixed, dropped in, started and street-tuned, break-in the engine and clutch and then have to have it dyno-tuned. So, it looks like I'll be bumming a seat for that event.

I don’t know if it is something that applies with your install but step back and see if you can remove bigger pieces or groups of pieces together. You may be surprised and get this sorted easier than you think. 

In reply to dean1484 :

This is what I'm working with. Can read the build thread here. I have most of the blower kit off already and most of the electrical stuff disconnected. I can probably have it out in a few more hours. And when I do whatever I have to do to the insides, I'm going to set it on the ground and crank it over with the starter and see if I have pressure BEFORE I drop it in.

I screeeeewed up. Got the engine out of the car in about 5 hours. Tonight got it on the engine stand, pulled the pan off aaaaaaaaaaaaaand I never torqued the oil pickup tube, causing it to suck air and refuse to prime. But, while I'm in there, I'm going to remove the oil pump and pack the pump full of grease as well

In reply to NickD :

Glad you found it! Did you check the bearings, or do you think they’re ok?

Kick ass. I'm glad it was that easy. 

In reply to Pete Gossett :

Didn't check the bearings, but it ran for maybe 10-15 seconds total and they were covered in Lubriplate assembly lube. No shiny stuff in the pan or oil, so I'm going to roll with it.

Great news man! Bummed you had to pull it,but a solid result. 

In reply to NickD :

Well like they say "To be old and wise, You must first be young and foolish"  Easy enough mistake to be made. One habit i got in to when building for customers is to use a paint pen to mark fasteners that are torqued to spec.  It also help show what was touched after the fact.  my own stuff i'll use a sharpie marker so i can look and see if its come loose.

Good luck on the 6th!

44

Disassembled the pump and packed it full of grease, torqued and loc-tited the pickup tube bolts, pre-filled the filter and cranked the engine over on the ground, and had oil coming out the pressure sender opening. So now its time to drop in and reinstall.

Never used grease for an oil pump.  I have used Vaseline.  Just melts and mixes into the oil.

And I am glad you found out what it was.  Did basically the same thing years ago when I assembled my own engine.

Oil pick up fell off the pump (Small block Chevy) a few days after I installed the engine.

NickD said:

Disassembled the pump and packed it full of grease, torqued and loc-tited the pickup tube bolts, pre-filled the filter and cranked the engine over on the ground, and had oil coming out the pressure sender opening. So now its time to drop in and reinstall.

Awesome!  I love it when the problem you think you have is actually solved by the attempted solution you implement!  Nice work!

doc_speeder said:

NickD said:

Disassembled the pump and packed it full of grease, torqued and loc-tited the pickup tube bolts, pre-filled the filter and cranked the engine over on the ground, and had oil coming out the pressure sender opening. So now its time to drop in and reinstall.

Awesome!  I love it when the problem you think you have is actually solved by the attempted solution you implement!  Nice work!

I'm just glad that when I took the pan off there was a visible issue. My fear was I was going to tear it down and not find a smoking gun. But Once I cut the pan loose, I happened to grab the pickup tube and it wiggled a good bit and that was my "Ah-Ha!" moment

noddaz said:

Never used grease for an oil pump.  I have used Vaseline.  Just melts and mixes into the oil.

And I am glad you found out what it was.  Did basically the same thing years ago when I assembled my own engine.

Oil pick up fell off the pump (Small block Chevy) a few days after I installed the engine.

Yeah, I used petroleum jelly. Just misspoke and said grease.