02 VVT oil pressure loss
 

My motor spun a bearing in September and the thread for that is here

I dropped the motor back in in January.

https://lh4.googleusercontent.com/-O...o/DSC_2802.JPG

Problem is that I continued getting the P0012 code. During the rebuild I had disassembled the VVT actuator and cleaned it so am confident I DO NOT need to use a high detergent oil to regain it's function. I also replaced the Orings in the "adapter".

I read every post I could find re the Miata P0012 code and decided to replace the ECU which did not help.

So I started suspecting OIL PRESSURE. The oil control system is a hydraulic system after all. After hooking up a mechanical pressure gauge to the port before the VVT actuator I found oil pressure that fluctuates wildly from 70psi peg with cold oil then falls on its face then back to 40, 60 and idles at <10 and maxes at ~40 with warm oil. So I started to blame the pressure relief valve in the oil pump and then replaced that. NO HELP :facepalm:

This video is oil temp @~190


This video is VVT oil line disconnected and gauge screwed into the block. 60+ PSI @ 3K AND IDLES @ 35 LBS!!!!!



So after much toil and coin I'm no closer to a ready to rock motor.

This oil pressure loss in the Oil Control System is what caused the engine failure to begin with. I have not revved this new motor over 6k more than twice for a short time and so when I dropped the pan to change the pump there was NO foreign matter in the bottom. So there's that.

I know the pressure is being lost in the VVT system but how and how to fix it?.

This thread has some nice info as to the oil flow of this system but where could the loss be?

I'm hoping you replaced the oil pump with one from Boundary Engineering or Mazda and not one from any other source because the VVT pumps are higher volume and some aftermarket suppliers with the local auto parts stores will fudge and say they are interchangeable.

What specific oil are you using? I'm interested in viscosity and not the additives.

Is there any evidence of the plastic base of the dipstick handle melting below the o-ring?

Speaking of o-rings, did your replacement oil pump come with a new one to go between the pump outlet and the block?

For Youtube videos, put the complete address from the top of the page including the "V=" and the string of characters that follows until you reach "&". You can cut the "&" and everything afterwards off. Just paste the address right in with the regular text and it will insert the video there.

Because this car will rarely hit the limiter and retains A/C and PS (street car) I bought the BP6D-14-100 from Rosenthal and it did not come with an Oring (Cheap Bastards) but I had one i used with fresh RTV gasket.

No, no melting on the dipstick handle. Why do you ask?

I seated the rings with 30w then change to Mazda spec 10-30 then tried 40w racing oil which only helped slightly til it warmed up. I'll run 10-30 T5.

It's getting nice out and I really want to drive. I'm fucking sick of working on this thing.




THANKS!!!!!!!!!!!!!!!!!!!!

The dipstick handle can melt within the tube and drip molten plastic into the oil, which then can block oil passages or partially hold open the oil pressure relief valve.

Ah. Nope none of that.

Could the #1 cam bearing be blown out so much that it doesn't keep back pressure in the OCV system? My thoughts are that no, you would likely see just a steady pressure loss and not the bouncing that is occurring.

http://i54.tinypic.com/voo9ag.jpg

http://i52.tinypic.com/2csdzck.jpg

None of you ballerz have a clue?

Ok I read this thread and your engine build thread, and watched your videos in this thread.

Question: Did you remove/clean the oil pressure relief valve in this pump? Is this a mazda VVT oil pump? Is this the pump from your previous motor that had metal in the oil?

Comments: Looks like your relief valve in the engine is sticking. Erratic pressure readings and all.

This is the Mazda VVT pump and I opened it up only to prime it. The erratic pressure had me thinking relief valve too which is why the new pump. Look at the second video again, mo more erratic pressure sans VVT circuit.

Re-replaced the O rings which improved the fluctuation issue but still once oil temp was ~200 maks pressure was 35 PSI.

Next step, pull cam journal and check clearance.

So with engine at idle and cold oil OP read 50 then actuate the solenoid and actuator does its job ,engine dies.


Oil temp reaches 130 then idle OP is 20 and 50 @ 3500rpm. Actuator does nothing at idle but advances timing @ 3.5k

OT hits 170 and idle OP is 15 and 3.5k OP is 35! Timing does not advance under this condition.

I have the #1 journal off but I can't find the plasti gauge so I'll pick up some tomorrow.

Sounds like something is loose. Try heavier weight oil, see if the pressure comes up to acceptable levels. If you've already tried a 10-40 try a 20W-50 motor oil with a new mazda filter. See if that helps enough. If not, you probably gotta pull the cams and check there, or the bottom end has to come apart.

I'd say that's a .004 specs for non VVT motor say .0014 to .003 with max .006

https://lh6.googleusercontent.com/-F...o/DSC_2843.JPG

Is this out of spec enough to cause the pressure loss?

Anyone know VVT journal clearance?

Clearly the journals were scoured but I don't know of any fix other than new head. No one local line bores and besides that would mean all new shims etc.

Ebay shop has reman head for $650 is the rough journals enough reason to spend that much cash?

I can't read the gauge as it's out of focus, but .004 clearance in one bearing is not your problem.

Yeah I'm eliminating possibilities. Where would you look next?

If I were you, I'd try a thicker oil and see what happens.

Basically there are 2 scenarios in my mind.

Scenario 1- if thicker oil = acceptable oil pressure, you're ok with that and it's "fixed".

Scenario 2- In your mind thicker oil is not ok even if it "fixed" the low oil pressure part, in which case you're going to likely be tearing down the engine. At least if you tried thicker oil now and had those numbers, that may help you pinpoint the problem.

There is no reason your car should need thicker oil on stock engine. just my .02

on another note:
Glanced at your thread a couple times per your PM request, and I'm really not seeing anything obvious, so I'm not of much help.

I had a P0010 on mine before, turned out to be wires from the solenoid going to the ecu, I guess they kinda pulled out a little bit from the plug/harness, wiggled them around and it never came back.

https://www.miataturbo.net/build-thr...0/#post1155484

Oh, this is a long shot from hell, but just a random though I had. You didn't remove, and then forget to reinstall your oil squirters did you? If that somehow happened, you'd have 4 holes bypassing oil that would certainly result in low oil pressure. Or maybe one of them fell out. Just a thought!

/\ that might be a possibility, since he did pull apart the whole thing to clean/rebuild

No they're in place I even checked them when I dropped the pan.

Don't forget this thing has fine oil pressure with the VVT oil line disconnected.

I've run 40w in it with no help.

I know that's why I said try 50W.

Regarding VVT line, dunno! If you think that's the issue, pull the vvt mechanism apart and have a look.