Alright boys I have tried my best at trying to sort this issue out but may need some help...here is a video of the issue I increased my vacuum suction from the oil filler neck with some bigger lines which has helped a ton with my puffing blue on deceleration but now this issue has snuck up. I have two lines from the oil filler to my oil catch can and using brake booster as the vacuum point. This noise happens after about 10-15 min or basically when the car is at full temp. I have removed the upper and lower manifold and replaced the metal gaskets with some rgasket maker after seeing they can be the issue from the forum and someone else having the same issue, however, problem still exists. So lately I have just vented one of the two lines at the filler neck and the noise never shows up but this is just a bandaid. I cannot seem to find the spot, it seems to be coming from the front of the motor and not near the manifolds. Where else could this leak be?

 

I can't listen to your video right now, but a few questions.

1. Why are you "using brake booster as vacuum point"? You don't need vacuum on a catch can. Typically just run the 2 lines to a catch can that has some sort of filter on it and you're done.

2. So do you have no upper/lower intake manifold gaskets, just using gasket maker? Where on the forum did you read to do that? The stock metal Mazda gaskets work amazing, they seal perfectly and last pretty much forever.

Dale

 

I had done a bunch of research before hand trying to figure that noise out. At first I fully thought it was a pulley but ran the motor with no belts and still had the same issue. After find another thread or two on different forums that had the same issue and a youtube video with the same noise, there were responses that the metal gaskets can get a small leak somewhere and cause such noise. I had pulled off one of my vacuum lines and that fully removes the issue but then of course the car doesn't like low idle but at least shows me it is a vacuum issue. The original thread starter ended up replacing his gaskets and that solved his issue. I only had gasket maker on sunday to at least try it out but didnt solve it. The reason I ended up at the break booster was only because it was a much bigger line to suck out the crank case pressure which as stated before did help solve my puffing blue on deceleration. I would much rather use pre turbo, but the pipe I have is maybe 4 inches long before the filter so there is not enough suction from that area at all (would like to get it fabbed to fit a long tube so I can use that location in the future).

 

It's a common misconception that the pipe before a turbo will "suck" something out. It won't. There is little to no vacuum there. Vacuum is created by a difference in pressure with a restriction between the two. A turbo's intake is just a reservoir of filtered air for the turbo to draw from, that's it.

On a rotary you just need to vent the oiling system so when you have expansion with heat it will have somewhere for that pressure to go. From the factory this is vented into the turbo inlet due to emissions regulations - the oil pan can give off evaporative emissions, so that has to be drawn into the engine, burned, and scrubbed by the cat.

You definitely don't want the catch can going to a true vacuum source like the brake booster line. That is past the throttle body on the engine so it will have actual engine vacuum at that connection.

I still haven't heard the noise so I can't give any input there yet. Metal gaskets can make noise if there's something that keeps them from sitting flat between the two flanges - like a piece of an old paper gasket that wasn't scraped off. That creates a gap and with the metal it can act like a reed in a musical instrument and whistle or hum with air flowing over it. But, if both surfaces are clean and true and it's bolted down right it's not going to leak. Again, Mazda did a really good job with the metal gaskets.

Dale

 

I will try again without pulling any crank case pressure out. Im just mainly trying to solve this issue of blue smoke on deceleration. Anytime I throw her in 2nd and let the rpms bring the speed down it loves to push oil thru the turbo. I have the turbosmart oil regulator in line and even purchased the 300psi adjustable valve that has been thrown up on the forum (im not restricting any however with this piece as at idle it says the turbo is seeing 20-30psi of oil which I dont think I want to restrict anymore. If im going down a hill and letting the rpms slow the car its just a consistant pumping of blue smoke....other then that at idle and undler load there is no blue smoke so im a tad confused.

 

Just listened to the video, WOW THATS LOUD!

Does the sound change with RPM? If so it could be a bad turbo - if the turbo hits the compressor housing it sounds crazy loud like that.

You can also do a drive with the oil cap off to rule out the crank case system. That will keep any pressure out of the crank case. You don't want to drive around all day like that but it's fine for testing.

Dale

 

Right!? Its super weird but for sure has to do with the vacuum pressure. I had sent the turbo out to my engineer to get looked at and he said there is nothing wrong (thought it was the cause to my blowing blue). That noise will only happen when im pulling all the crank case pressure out with the vacuum line. I have two lines that come off the oil fill and im just venting one of those to atmosphere and the sound goes away completely. Its super weird as it fully sounds like it is coming from the front of the motor near the pullies (I have made sure it has nothing to do with them)...once I put my head past the alternator and listen to the top of the engine its not as loud. You maybe right about pulling pressure out tho but I do find I blow more smoke with when im not pulling any out but will try again with both of the lines going to the oil catch can then just venting to atmosphere