DIY: Vacuum leaks and bad oil injectors solution.
There is no AIR PRESSURE in the injector nozzle...just like there isn't pressure under an airplane wing ( In an NA car 
)
There is AIR FLOW through the nozzle...but is is a result of suction pulling air into the combustion chamber in the intake stroke
The OMP is a positive displacement pump with oil output dependent on the stroke of the 2 pistons.
The flapper valve is there to keep the oil from backing up into the air inlet chamber down the feed line. The amount of oil injected will be cleared from the injector by the amount of airflow into the nozzle. There is much more airflow than oil flow...and the injector has a small reservoir where the flapper is that is bigger than the amount of oil injected.
In order for oil to flow back into the intake from this system in large enough amounts to be noticeable would require all 4 injector nozzles to be completely plugged. That would be the only way that the airflow into the other injectors wouldn't just suck in the oil through them and into the engine
As per the heat issue.....the OMP end will see heat from the exhaust manifold that will cause it to potentially get warmer than 200 degrees. The injector end will be limited to coolant and oil temp maximums...that are way below 300 degrees ...more likely 200 at most times. Can't see that being an issue
I think there seems to be some misinformation about the role of the flapper valve.....it is designed to stop oil from back flowing...not to block off the airflow
)There is AIR FLOW through the nozzle...but is is a result of suction pulling air into the combustion chamber in the intake stroke
The OMP is a positive displacement pump with oil output dependent on the stroke of the 2 pistons.
The flapper valve is there to keep the oil from backing up into the air inlet chamber down the feed line. The amount of oil injected will be cleared from the injector by the amount of airflow into the nozzle. There is much more airflow than oil flow...and the injector has a small reservoir where the flapper is that is bigger than the amount of oil injected.
In order for oil to flow back into the intake from this system in large enough amounts to be noticeable would require all 4 injector nozzles to be completely plugged. That would be the only way that the airflow into the other injectors wouldn't just suck in the oil through them and into the engine
As per the heat issue.....the OMP end will see heat from the exhaust manifold that will cause it to potentially get warmer than 200 degrees. The injector end will be limited to coolant and oil temp maximums...that are way below 300 degrees ...more likely 200 at most times. Can't see that being an issue
I think there seems to be some misinformation about the role of the flapper valve.....it is designed to stop oil from back flowing...not to block off the airflow
There does not need to be any "blockage" of anything let alone 4 injectors to allow oil back into the vacuum lines leading back to the intake, because they're under vacuum, in fact blockage has naught to do with it, it's a side issue. It's a failure of the diaphragm (aka flapper valve) that will allow oil to back flow into even one injector. It is the only membrane between oil and air from vacuum and it if it fails oil can be sucked back into the intake through the vacuum system.
But anyway I knew this would be contentious as it's a different point of view from a different source, I put it out there up to those reading to do with it what they want. BTW OP the vacuum numbers come from the specs of the injector that are used to check it with a vacuum tester, Google search it if you can't find it here.
Last edited by FunRun8; Nov 22, 2015 at 11:21 PM.
Logalinipoo.....the ball bearing valve you have inserted should work similar to the flapper valve. It has added a ball bearing seal instead of the rubber flapper.
The oil will potentially back up towards the valve when the oil is injected...but as discussed earlier with the amount of oil and airflow through the system....it is unlikely that it will get to to the valves anyway
You may have slightly less airflow through the valves.....but I think the nozzle is still the restriction so shouldn't matter
The oil will potentially back up towards the valve when the oil is injected...but as discussed earlier with the amount of oil and airflow through the system....it is unlikely that it will get to to the valves anyway
You may have slightly less airflow through the valves.....but I think the nozzle is still the restriction so shouldn't matter
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
DIY: Vacuum leaks and bad oil injectors solution.
Just keep ignoring simple things and proving how little you know about this.
Yes, that is test numbers for what it should hold. That is not intake vacuum pressures. In fact it is the opposiate. It is the pressure the omp should exert. And a test to make sure the flapper can restrain that pressure.
Again simply remove the hose and put your finger over each hole. The hose will have a continously suction. The accordion might have a extremely slight vacuum. But it will be much less than the hose.
Yes, that is test numbers for what it should hold. That is not intake vacuum pressures. In fact it is the opposiate. It is the pressure the omp should exert. And a test to make sure the flapper can restrain that pressure.
Again simply remove the hose and put your finger over each hole. The hose will have a continously suction. The accordion might have a extremely slight vacuum. But it will be much less than the hose.
Last edited by logalinipoo; Nov 23, 2015 at 01:44 AM.
I was with you on everything right up until you mentioned this, it is not correct, everything else echoes my posts nearly exactly..
There does not need to be any "blockage" of anything let alone 4 injectors to allow oil back into the vacuum lines leading back to the intake, because they're under vacuum, in fact blockage has naught to do with it, it's a side issue. It's a failure of the diaphragm (aka flapper valve) that will allow oil to back flow into even one injector. It is the only membrane between oil and air from vacuum and it if it fails oil can be sucked back into the intake through the vacuum system. Which way do you think the airflow is going here??
But anyway I knew this would be contentious as it's a different point of view from a different source, I put it out there up to those reading to do with it what they want. BTW OP the vacuum numbers come from the specs of the injector that are used to check it with a vacuum tester, Google search it if you can't find it here.
There does not need to be any "blockage" of anything let alone 4 injectors to allow oil back into the vacuum lines leading back to the intake, because they're under vacuum, in fact blockage has naught to do with it, it's a side issue. It's a failure of the diaphragm (aka flapper valve) that will allow oil to back flow into even one injector. It is the only membrane between oil and air from vacuum and it if it fails oil can be sucked back into the intake through the vacuum system. Which way do you think the airflow is going here??
But anyway I knew this would be contentious as it's a different point of view from a different source, I put it out there up to those reading to do with it what they want. BTW OP the vacuum numbers come from the specs of the injector that are used to check it with a vacuum tester, Google search it if you can't find it here.
Think about how little oil is actually injected...and notice that there is quite a bit of room between the flapper and the hole in the injector...and then think about the airflow on the intake stroke. How much oil do you think is going to back feed unless the injector nozzle is plugged.....I would expect none.....If you had positive pressure in the nozzle blowing back toward the intake...Maybe a bit....but there is no way the small amount of oil that is injected is going back down the hose that has air flowing the other direction
( unless you think the air is actually flowing in reverse from where it actually goes??)
If the seal was important then I would expect the original poster to have issues with oil getting back into his intake.....
Funny how people fail to recognize that this could cause an easy death to the engine that you likely can’t afford to replace. Buying a new set of oil injector nozzles from Mazda probably makes too much sense for some people to understand ...
Thread
Thread Starter
Forum
Replies
Last Post
drebbrnator
Series I Trouble Shooting
11
Dec 27, 2018 07:02 PM
9krpmrx8
Series I Trouble Shooting
23
Nov 5, 2015 11:45 PM
