So I was in the process of replacing my OMP lines and I did the FSM test on the nozzles. I am able to blow through them and they leak the other direction. I've been reading that these nozzle DO NOT work on vacuum and should never be hooked to boost. So my question is, if the check valve in the nozzle goes bad, can't I jut put an external check valve inline with the line to it to allow me to "blow" through the nozzle but not "suck"? I really don't see the harm in it. Its just a cheap mans way to fixing the nozzles right? If the check valve in the nozzle is bad than it would cause oil to blow by the nozzle whilst the engine is under boost and thus send oil into my primary turbo inlet.

So to reiterate, can I use one of Dale Clarks infamous viton diaphragm check valves as an external check valve to the oil nozzle?

 

I wonder if the check valve protects the OMP from boost pressure as well?

You're idea seems reasonable. I'm curious if anyone else has done this and what the results have been.

 

I ordered new ones from ray but I thought I'd dick around with my old ones and see what I can figure out. It appears that the diaphragm of the check valve is a rubber stopper of a sort. I'll post a picture later. I read a post of someone named Aaroncake who suggested soaking them in carb cleaner. I decided to take it a step further. I hooked up my Mityvac with the bleed container inline and applied vacuum against the leaky side of the check valve. After a few drink it cleaned it up quite well! I have a picture of the debris in the check valve that it cleared out. Not only that, on one of the two nozzles, I was able to get it to hold vacuum after this bleed form of cleaning! I then took it too far and broke it. By applying too much vacuum to the check valve, I lodged it and it would not flow in either direction afterwards.

So from my observations, I believe adding an external check valve would not cause an issue and could be a potential band aid fix. If I were to try cleaning them again, I would try something more safe for rubber parts.

 

I think the check valves in the OMP nozzles are designed just like the stock check valves, with rubber flappers that can fail. Really, I'm not totally sure that they are absolutely needed for them to work right, I know many people just vent to atmosphere. The vacuum line might be needed more so for emissions purposes (evaporative emissions) than function.

But, yes, some of my check valves (or just one T'd in) would likely do the job but they would need to be stuck open.

Someone cut a oil injector open once and took pics, can't remember where I saw it, that was ages ago.

Dale

 

I believe you're absolutely right regarding that it is emissions related. However i do not believe the check valve has to be stuck open. The check valve is only in place to prevent boost produced by the motor from pushing the oil back through nozzle into the primary turbo inlet. Someone made a very informative post using a metaphor of someone drinking soda through a straw and having the straw tee'd to "meter" the amount of soda fed to the person drinking regardless of the strength of the person sucking. In turn that is how the oil nozzles work. Venting the nozzles to atmosphere is technically the same thing but my issue with it is in the event your nozzle check valves go bad (some as soon as 5k miles!) then under boost the motor will spit oil out of those nozzles. Even if you have a filter i still believe a check valve in place in beneficial to the proper lubrication that the omp provides.

I'm replacing my omp nozzles today and will keep this thread updated with the lifetime of the nozzles. Also i will be cleaning out my y pipe tracts and all my inlets of oil to see if this alleviates the "oil in the intake" problem that seems oh so common. In the event one of my nozzles prematurely fails I absolutely will put a check valve of yours in place and observe the results. I will also be premixing as a fail safe in the event my theory is wrong but it seems rock solid!

Let me know what you think.
Matt

 

+1 on the pre-mix. It's good backup.

 

My newer style check valve (one of them) failed after 5k miles and shot out oil under boost... I believe it failed because I had the line open to atmosphere and it just sucked up too much crap out in the desert where I track my FD. It's definitely a good reason to have a filter on it as Mazda did... I think I'll be running a clear line from the oil check valves to the top of my filtered Jazz oil catch can.

 

Dale:
the check valves are absolutely required; without them the engine will receive no lubrication from the OMP except when running under atmospheric pressures. The valves are disc / spring type of design. They allow filtered air from the primary compressor inlet (in stock configuration) to mix with the oil under engine vacuum conditions for better dispursal in the chambers. Under boost conditions, the OMP injects the oil; the check valves then prevent oil from being blown out and down into the inlet of the primary compressor. The check valve location is also important as it limits the annular space for oil pooling; This was a problem in the first production runs (1992-1993) and eventually corrected by the installation of the rubber grommet under the check valve. It is essential the check valves are there and operating correctly.

 

So are aftermarket check valves like Dale's a good idea for a replacement? Or is it still best to stick with the OEM design even though it's known to fail?

 

I honestly see no downsides to running dale's check valves as a supplement, fix, fail safe, or any other the above. Because of the design I do not see a need to have to run one to each nozzle. I believe both nozzles run into a common hard line on the rats nest so a single check valve may be added after the hard line to be applicable to both nozzles

 

I guess my other question is that if I think my check valves have failed, should I assume that my oil injectors have failed completely?

 

The injectors themselves are not what you think. Its not necessarily an injector, but more so a banjo bolt with a vacuum nipple and a check valve. If you can suck through your injectors then the check valves have failed. The consequence is you are not receiving proper lubrication under boost! I suggest adding a check valve from dale after the hard line or replacing them. The check valve orientation would be towards the injector. So you should be able to blow through it into the motor but not suck .

Hope this helps!
Matt

 

That makes sense Matt, but let me rephrase my question. If we're to assume that if the oil is coming out of the check valves that it's not going into the motor and therefore our "injectors" have failed (check valve). If we merely place a better check valve in the fresh air hose directly after the stock valve is that going to fix the problem, or merely stop the oil leak?

I realize that I may be asking a rhetorical question and that if the oil is not going out of the "fresh air" lines, then it has to be going into the motor....I just want to make sure my understanding of that is correct.

 

Dual in-line check valves may make sense. Without any check valves the engine will see no lubrication from the OMP under boost conditions. It is important, however, to have a functioning check valve right over the orifice so the annular oil space is as small as possible. The greater the annular space is the bigger lag there will be between engine vacuum conditions and boost conditions when the OMP steps up to the higher oil flows. It was noted in the FD's produced in 92 and 93 that the oil was evacuated from under the check valves during engine vacuum conditions then when boost came on the OMP had to refill the annular space before the engine could see any oil. They then put the rubber filler between the check valves and orifice.

 

Now that I think about it you may be right about using dual check valves and also having them as close to the nozzle as possible. I recall as an elementary school student we went to a science museum and one exhibit explained gravity in a chamber with air and a chamber with vacuum. There was a feather and a fishing weight in the tube, when the tube was inverted, the feather obviously fell slower than the weight. After the chamber evacuated all the air the chamber under vacuum), once the tube was inverted, the feather and the weight fell at the same speed! So my hypothesis is that even under a pressurized condition, maybe the feather and fishing weight would fall at the same speed. So if you catch my drift, even under a steady pressurized setting, the oil would still be metered at the mercy of the OMP. a bad check valve in a pressurized setting would cause a turbulence in the metering orifice and thus blowing the oil out and not allowing it to enter the combustion chamber. Can any physics experts chime in and provide some more expert opinion if my theory holds water?
Matt

 

Any news about this?

I'm rebuilding my engine and found that my two oil nozzles fail when applying vacuum. I'd like to install a check valve on each of them instead of replacing with two new nozzles that may fail in a few months.

Thanks

 

I have tested five in line check valves and the issue is the cracking pressure. To prevent the engine vacuum from scavenging oil the check valves must open with just a few inches of water pressure.

 

So there is actually no fix except replacing the nozzles with new ones? Is there some nozzles that are less prone to failure? Maybe FB, FC or RX-8 nozzles?

 

I second mine failing. I can blow through them and suck air through them as well. I am replacing my FPD and all injector o rings and Insulators, so I am already there. Instead of putting one check valve in line at the turbo compressor housing, I might as well put one in each vacuum line between the injector and the rats nest connection. I really don't see why this wouldn't work...

Trev

 

Exactly. The check valve in line (preferably closer to the nozzle) will still act the same as the stock one inside. An above atmospheric state will still allow the oil to be gravity fed into the engine. The oil will no back track up to the external check valve to "cover the extra area". As long as the check valve doesn't fail, you should be good.

I'm currently deployed right now and my new nozzles have roughly 500 miles on them since I replaced them in January. I'll be checking them when I get home to ensure they're still in working order. I'll update this thread as mileage increases and I'll post results in the event they fail and I add external valves.

Matt

 

Good info Matt, thanks!

 

Did you try with Dale Clark's check valves? I have two spare check valves in stock that I could use in line with the oil nozzles.

 

Just bought two more from Dale for my OMP lines!

Trev

 

I think this is something I'm gonna do to my car as well . I think the oil injector check valves that are built into the injectors are similar in design to the turbo control line check valves. They do terrible with heat, and that close to the engine heat will REALLY kill them off.

My Viton check valves should work perfectly in that application. If anyone wants 2 to plumb in-line to the check valves, I'll do $10 shipped for the pair. Or, if you want 6 check valves to do the OMP valves and the other check valves, $30 shipped.

Dale

 

Exactly...I would start making this a 6 viton kit!

Trev