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-   -   No Oil Pressure (https://www.miataturbo.net/engine-performance-56/no-oil-pressure-54083/)

Preluding Dec 14, 2010 12:28 PM


Originally Posted by pschmidt (Post 668915)
I had no issue witht he subframe bolts. The 4 near the back were covered in factory undercoating. The two on each side near the control arms broke free with no drama as well. I live in the mid-atlantic area; the local DOT loves their salt.

To take the subframe out you have to remove:
swaybar
lower shock bolt
calipers (let them hang off the shock)
steering rack
motor mounts
subframe (support the trans with a jack before you drop the subframe)

I did this on the ground with the help of a friend. Removal took 4 hours, installation took another 5 or so while tidying up some things and bleeding the brakes (unrelated). Both ways were done with copious amounts of alcohol

Sounds like a decent route to take....swaybar bolts could be a good time....
I'll keep updating things

TravisR Dec 16, 2010 05:47 PM


Originally Posted by Preluding (Post 668797)
Borrow a little air pig from a friend last night. Filled the Oil feed line with some thick oil and shot 100psi down it a few times.... no luck... Looks like this is unavoidable.

Another question if anyone is listening though. Can I lift engine enough with the top of transmission attached to take off oil pan????

Once those valves get stuck, its a matter of time before they get stuck again. That design is REALLY poorly done, unfortunately that's what were stuck with.

Preluding Dec 16, 2010 07:38 PM

........fuck, I hate this.

magnamx-5 Dec 18, 2010 11:06 AM

just pull the whole assembly dude its way easier to get everything right when it is out of the car. Laying on your back while the motor is suspended over you head on some chains sucks and is definatley not safe. You can keep on fucking around and end up taking 20 times longer doing more work or you can just man up and do the shit. buy a new pump while you are at it.

fooger03 Dec 18, 2010 12:08 PM

I pulled and replaced mine no fewer than 3 times during my rebuild....

....I'm getting really good at it now....

....I would still rather put my hand on the ground and have someone hit it as hard as they can with a sledgehammer

It sucks, but believe me, when you get to the point where you aren't worried about shit breaking every trip you make, it's a satisfying feeling.

Preluding Dec 20, 2010 07:29 AM

Thanks for the words of encouragement. Seeing as how its well below freezing outside, I'm insulating my garage right now to prepare for it.

Preluding Mar 15, 2011 08:44 AM

4 Attachment(s)
HOLY SHIT ITS AN UPDATE!!

OK...I dropped my subframe, moved the alternator, PS pump and AC pump/bracket. Then a pulled the oil pump.

I've attached pictures BUT to make a long story short. Everything looks A1.

My pickup tube seemed to be attached and fairly tight and not clogged, the relief valve is firm at the end of the pump and moves nicely. My oil pump gears are also looking great and move nicely.

WHY THE HELL DIDN'T I HAVE OIL PRESSURE THEN?!?!?!?!?!?!? :facepalm:

To make things worse... my crank looks like it might be slightly cooked. There is rainbow discolouration around cyl #3 main and rod cap bearing.

Anyways, I've attached the pics and Crank and 2 of the oil pump showing relief valve and gears.

PLEASE HELP, not gonna lie......I'm thinking of making an epic part-out thread right now.

I'll go out and try to measure everything I can.

TravisR Mar 15, 2011 11:31 AM

So I've seen this before as well. It may or may not be the problem, but this is my strongest guess...

I sold a set of gears to a guy who was having his motor assembled in Indianapolis, allegedly these people made F1 engines that won races from lego blocks or whatever. So they were infallible... The gears all say that they are drop in, but I tell people to check them against their housing anyways. This makes sure people put them in the right year of housing, and that the housing is not worn. The shop said they did check it in the housing, and they bolted the pump up to the block filling it with an assembly lube as they went. The assembly lube acts as a super primer, your tolerance in your oil pump could be off by an 1/8th inch and it would prime and pump (no really verified!)

What had happened is that they inserted my oil pump gears into the wrong style of housing, so they were literally nearly .1 inches of clearance. They alleged that they had tested the gears in another housing and then switched them into this better housing for final assembly(right...). The heavy assembly oil got things siphoned up the tube, and got the oil flowing. Once the oil is up in the gears the viscosity of the oil itself is strong enough to create the seal and keep it working. Once you turn the vehicle off and drain it of all oil the air doesn't have enough viscosity to suck the oil up the tube again. These means the pump never primes, so you get the infamous one shot wonder oil pump. You could verify this by putting your Miata on a steep inbankment and letting the oil flow down onto the oil pump and then turning the engine on. This should properly prime it for operation and it will work again.

So what I would do is go in and check the width clearance in the housing. Width clearance should be less then or equal to .06 (manual says .055 but .06 is fine) Radial and tip clearance are important, but only for total oil flow not for menial pumping and priming operation. Besides if there was something wrong with those clearances you would see it!

Thats my best guess, break out the plastigauge!



Originally Posted by Preluding (Post 701630)
HOLY SHIT ITS AN UPDATE!!

OK...I dropped my subframe, moved the alternator, PS pump and AC pump/bracket. Then a pulled the oil pump.

I've attached pictures BUT to make a long story short. Everything looks A1.

My pickup tube seemed to be attached and fairly tight and not clogged, the relief valve is firm at the end of the pump and moves nicely. My oil pump gears are also looking great and move nicely.

WHY THE HELL DIDN'T I HAVE OIL PRESSURE THEN?!?!?!?!?!?!? :facepalm:

To make things worse... my crank looks like it might be slightly cooked. There is rainbow discolouration around cyl #3 main and rod cap bearing.

Anyways, I've attached the pics and Crank and 2 of the oil pump showing relief valve and gears.

PLEASE HELP, not gonna lie......I'm thinking of making an epic part-out thread right now.

I'll go out and try to measure everything I can.


Preluding Mar 15, 2011 11:38 AM

Thats a good story...but this is a 100% stock unmodified pump. Hell...the cover has never been off the gears until yesterday when I went at it.

Anyone ever see the oil galley in the block clogged??? likey/not likely???

I'm replacing the pump anyway at this point...I would hate this not to be the problem. Definately cranking the engine before I put up subframe too and everything too, just to be safe.

TravisR Mar 15, 2011 11:52 AM

The moral to the story is that if the side clearance is too wide the pump will only prime and pump once. Stock pumps have worn to more then .08 from normal operation in 30,000 miles. There is no guarantee your stock pump isn't out of spec.

There are very few things that can happen with no oil pressure.
Large leak post pump(and by that I mean you forgot to put an oil filter on)
Clogged pre filter screen
Improper pickup tube fastening
Improper clearances in oil pump
Relief valve in the full open position
Low fluid level

If there was a blockage down stream of the pump the oil pressure would be extremely high.

Preluding Mar 15, 2011 11:56 AM

PS...Travis, PUMP ME UP.

TravisR Mar 15, 2011 11:57 AM

Ok, I was just wanting to make sure we were fixing the problem by getting you one of my pumps.

Preluding Mar 15, 2011 12:01 PM

Well I'm not going to mess with it...buying new pump and pick-up tube....

Now for those 2 pictures with rainbows on them....Why would the crank have discolouration and not the rod and bearing cap itself? Could i have overlooked this when I assembled the engine to begin with??

Preluding Mar 15, 2011 12:06 PM

Clogged pre filter screen - Checked, not clogged
Improper pickup tube fastening - Checked, nice and tight
Improper clearances in oil pump - NOT checked
Relief valve in the full open position - Checked, see pic.
Low fluid level - Checked, not low...added more after no oil pressure and overfilled just to be sure.

I guess clearances in the pump is the only thing left... and I don't know anything about measuring... when I get pump, I throw it in...that is all.

TravisR Mar 15, 2011 12:08 PM

I wouldn't worry about it, unless the bearing itself is too tight it won't happen again with proper oil flow. Its unlikely you super heated it to the point where it changed the material properties...

Preluding Mar 15, 2011 12:13 PM


Originally Posted by TravisR (Post 701735)
I wouldn't worry about it, unless the bearing itself is too tight it won't happen again with proper oil flow. Its unlikely you super heated it to the point where it changed the material properties...

Thats what I like to hear... I'll still take the rod bearing and half a main bearing out (gonna bring them into machine shop that assembled my block for me)

Now pm me back

ftjandra Mar 15, 2011 12:24 PM

Did you actually take apart the relief valve? The picture that you took is the bottom of the relief assembly and pressing in that area does not mean anything. In your second picture, the hole on the bottom right by the outer gear, you should see the plunger there. I.e. that hole should be fully blocked by the plunger. Is it?

--Ferdi

Preluding Mar 15, 2011 12:45 PM


Originally Posted by ftjandra (Post 701745)
Did you actually take apart the relief valve? The picture that you took is the bottom of the relief assembly and pressing in that area does not mean anything. In your second picture, the hole on the bottom right by the outer gear, you should see the plunger there. I.e. that hole should be fully blocked by the plunger. Is it?

--Ferdi

Didn't take it apart...just looked... I'll get into it tonight and check.

magnamx-5 Mar 15, 2011 01:01 PM

check your oil squirters if one has cracked or failed then you wont be able to make oil pressure.

Preluding Mar 15, 2011 01:52 PM


Originally Posted by magnamx-5 (Post 701766)
check your oil squirters if one has cracked or failed then you wont be able to make oil pressure.

really??? did not know that... that seems a lot more likely...might even remove them if thats the case....


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