Please not another crankcase ventilation thread.
#121
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Please don't deviate the conversation to something else, and what about debating on using a catch can with -10an breather line from valve cover - catch can to down pipe??
#122
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there was great debate on this over on the dsm forums (i used to have an evo 3)
Consensus was to swap out the pcv for a 3/8" check valve and run a baffled and filtered catch can which reconnects to the intake. Those motors dump tons of oil in the head which causes issues when venting any pressure from the valve cover, people started to vent from an inspection hole on the block as well as the dipstick. This was also just before the forward facing turbo became a craze and everyone just went with huge lines to a VTA setup.
While not the same motor the same basic principles apply.
![](https://www.miataturbo.net/attachments/engine-performance-56/153709-please-not-another-crankcase-ventilation-thread-26aba055.jpg?dateline=1446161588)
Suction tube on turbo intake
![](https://www.miataturbo.net/attachments/engine-performance-56/153710-please-not-another-crankcase-ventilation-thread-9cd16b1b.jpg?dateline=1446161588)
Inside shot of the suction tube. Same concept as the vibrant piece.
![](https://www.miataturbo.net/attachments/engine-performance-56/153711-please-not-another-crankcase-ventilation-thread-9fd5e28e.jpg?dateline=1446161588)
I deleted the baffles in the valve cover and just ran a splash guard
![](https://www.miataturbo.net/attachments/engine-performance-56/153712-please-not-another-crankcase-ventilation-thread-9df7dd4e.jpg?dateline=1446161588)
Said baffled and filtered can which I am reusing on the Miata
In the end I did not get to log pressures but on a freshly built motor after 1500 miles the can was clean as was the intake.
Consensus was to swap out the pcv for a 3/8" check valve and run a baffled and filtered catch can which reconnects to the intake. Those motors dump tons of oil in the head which causes issues when venting any pressure from the valve cover, people started to vent from an inspection hole on the block as well as the dipstick. This was also just before the forward facing turbo became a craze and everyone just went with huge lines to a VTA setup.
While not the same motor the same basic principles apply.
![](https://www.miataturbo.net/attachments/engine-performance-56/153709-please-not-another-crankcase-ventilation-thread-26aba055.jpg?dateline=1446161588)
Suction tube on turbo intake
![](https://www.miataturbo.net/attachments/engine-performance-56/153710-please-not-another-crankcase-ventilation-thread-9cd16b1b.jpg?dateline=1446161588)
Inside shot of the suction tube. Same concept as the vibrant piece.
![](https://www.miataturbo.net/attachments/engine-performance-56/153711-please-not-another-crankcase-ventilation-thread-9fd5e28e.jpg?dateline=1446161588)
I deleted the baffles in the valve cover and just ran a splash guard
![](https://www.miataturbo.net/attachments/engine-performance-56/153712-please-not-another-crankcase-ventilation-thread-9df7dd4e.jpg?dateline=1446161588)
Said baffled and filtered can which I am reusing on the Miata
In the end I did not get to log pressures but on a freshly built motor after 1500 miles the can was clean as was the intake.
#123
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I run a catch can on each side. I put 6k miles on with no boost and never saw a drop of oil in the driver side can. 150 miles while boosted produced a little oil in the driver side can. So wherever you don't want oil, put a catch can.
#125
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I *believe* the MSM setup is the following: The MSM uses a PCV "catch drain". Gasses are expended out of the PCV out port in the valve cover and then pass to a separator can which separates the liquids from the gasses. The gasses then pass through the PCV valve and make their way to the intake. The liquids that get separated travel downward through a pipe and make their way back to the oil pan, similar to the way our turbo drain lines return to the oil pan. I suspect that this drains to a location below the oil level though.
#126
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i did a little experiment that involves the vibrant crank case evacuation kit. remember i have a ls1 and i can listen to drag racers tricks with a little more confidence.
![](https://www.miataturbo.net/attachments/engine-performance-56/153915-please-not-another-crankcase-ventilation-thread-80-demonstartion_60eba8960c041fc4c3a22e101384eb45998a26fb.jpg?dateline=1446475329)
i removed the pcv off my engine due to a ton of oil that gets dumped into the intake. i replaced it with a Joes-racing-dry-sump-catch-can. after driving around with it, i noticed the catch can would vent off some really nasty smells and fill the cab with blow by/exhaust. so i went looking for an alternate arrangement. i found on yellow bullet (drag forum) that guys where using the crank case evacuation kits to pull a vacuum. i don't care about the added hp of having a crankcase under vacuum. I just wanted the blow by to be vented somewhere not under my hood, i gave it a shot.
i welded the kit into my headers, added a check valve, and tested it. it pulled a large vacuum under deceleration. it pulled about 5 in of vac. worried i had too much back pressure i moved the kit and plumbed it 12" away from the exhaust tip. behind the muffler. same thing 5in under deceleration. under idle and driving around it would pull between 1 and .5 in. seeing the vac i felt confident that the air was moving the the correct direction and was happy to test it out on a track.
I took the car out to Daytona this weekend. thing worked great, fumes where gone. the only problem was the line was so long it filled up with oil. coming out of turn 5 i blew 1/2qt of oil threw my exhaust. huge bellow of smoke and got blacked flagged. i had to go back to the old catch can to finish my runs. i'm going to add an oil air separator and continue using the evac kit.
![](https://www.miataturbo.net/attachments/engine-performance-56/153915-please-not-another-crankcase-ventilation-thread-80-demonstartion_60eba8960c041fc4c3a22e101384eb45998a26fb.jpg?dateline=1446475329)
i removed the pcv off my engine due to a ton of oil that gets dumped into the intake. i replaced it with a Joes-racing-dry-sump-catch-can. after driving around with it, i noticed the catch can would vent off some really nasty smells and fill the cab with blow by/exhaust. so i went looking for an alternate arrangement. i found on yellow bullet (drag forum) that guys where using the crank case evacuation kits to pull a vacuum. i don't care about the added hp of having a crankcase under vacuum. I just wanted the blow by to be vented somewhere not under my hood, i gave it a shot.
i welded the kit into my headers, added a check valve, and tested it. it pulled a large vacuum under deceleration. it pulled about 5 in of vac. worried i had too much back pressure i moved the kit and plumbed it 12" away from the exhaust tip. behind the muffler. same thing 5in under deceleration. under idle and driving around it would pull between 1 and .5 in. seeing the vac i felt confident that the air was moving the the correct direction and was happy to test it out on a track.
I took the car out to Daytona this weekend. thing worked great, fumes where gone. the only problem was the line was so long it filled up with oil. coming out of turn 5 i blew 1/2qt of oil threw my exhaust. huge bellow of smoke and got blacked flagged. i had to go back to the old catch can to finish my runs. i'm going to add an oil air separator and continue using the evac kit.
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Last edited by OGRacing; 11-02-2015 at 10:00 AM.
#128
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Just to add, this is with a simple Husky catch can between the PCV and intake manifold. N/A engine, was a daily and saw regular track use (until I got a Miata).
BEFORE pic (left) was in 07/08 with ~75k miles and pulled it off recently now at 129k miles to take the AFTER pic (right).
In the BEFORE pic (left), I am not sure if I took the picture before or after cleaning it (can only clean so well inside a manifold), but regardless, 7+ years/55k miles later, it is not that dirty especially compared to some pictures I've seen of some VICS manifolds taken apart to clean the EGR passages.
![](https://www.miataturbo.net/attachments/engine-performance-56/153919-please-not-another-crankcase-ventilation-thread-22639758975_76f3c916b3_b.jpg?dateline=1446487307)
It is an N/A engine, so take it as you may, but in my eyes, catch can between PCV and IM seems to work well enough. Of course, FI applications will be different.
BEFORE pic (left) was in 07/08 with ~75k miles and pulled it off recently now at 129k miles to take the AFTER pic (right).
In the BEFORE pic (left), I am not sure if I took the picture before or after cleaning it (can only clean so well inside a manifold), but regardless, 7+ years/55k miles later, it is not that dirty especially compared to some pictures I've seen of some VICS manifolds taken apart to clean the EGR passages.
![](https://www.miataturbo.net/attachments/engine-performance-56/153919-please-not-another-crankcase-ventilation-thread-22639758975_76f3c916b3_b.jpg?dateline=1446487307)
It is an N/A engine, so take it as you may, but in my eyes, catch can between PCV and IM seems to work well enough. Of course, FI applications will be different.
#129
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the vibrant thing-ama-bob is a -10an line. i had some aluminum hard line sitting around and ran that the rear axle, then used 12" of braided stainless that also i had lying around. i did need to use a -10 to -6 to pick up the 3/8 hose that comes off the valve covers.
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Last edited by OGRacing; 11-02-2015 at 01:28 PM.
#130
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While down in the basement recently, I happened to take notice of the crankcase ventilation provisions on the V-12 engine which powers one of our backup generators:
![](https://www.miataturbo.net/attachments/engine-performance-56/154413-please-not-another-crankcase-ventilation-thread-80-genny2_ed8c4e5ca8d2583e4e9fe62cc7d90fc3d3063d4b.jpg?dateline=1447084542)
![](https://www.miataturbo.net/attachments/engine-performance-56/154414-please-not-another-crankcase-ventilation-thread-80-genny_77aa7ac1ed3b84e26e750a1bf0da62942a9b849a.jpg?dateline=1447084542)
Not much to it. I'm looking, in particular, at the pipe which comes off of one of the rocker covers on each side, and just leads down to the floor. In the first picture, you can see a puddle just below this tube.
![](https://www.miataturbo.net/attachments/engine-performance-56/154413-please-not-another-crankcase-ventilation-thread-80-genny2_ed8c4e5ca8d2583e4e9fe62cc7d90fc3d3063d4b.jpg?dateline=1447084542)
![](https://www.miataturbo.net/attachments/engine-performance-56/154414-please-not-another-crankcase-ventilation-thread-80-genny_77aa7ac1ed3b84e26e750a1bf0da62942a9b849a.jpg?dateline=1447084542)
Not much to it. I'm looking, in particular, at the pipe which comes off of one of the rocker covers on each side, and just leads down to the floor. In the first picture, you can see a puddle just below this tube.
#131
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you have a V12 in the basement?
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#133
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just not a normal thing to see in a residential basement.
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#137
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While down in the basement recently, I happened to take notice of the crankcase ventilation provisions on the V-12 engine which powers one of our backup generators:
![](https://www.miataturbo.net/attachments/engine-performance-56/154413-please-not-another-crankcase-ventilation-thread-80-genny2_ed8c4e5ca8d2583e4e9fe62cc7d90fc3d3063d4b.jpg?dateline=1447084542)
![](https://www.miataturbo.net/attachments/engine-performance-56/154414-please-not-another-crankcase-ventilation-thread-80-genny_77aa7ac1ed3b84e26e750a1bf0da62942a9b849a.jpg?dateline=1447084542)
Not much to it. I'm looking, in particular, at the pipe which comes off of one of the rocker covers on each side, and just leads down to the floor. In the first picture, you can see a puddle just below this tube.
![](https://www.miataturbo.net/attachments/engine-performance-56/154413-please-not-another-crankcase-ventilation-thread-80-genny2_ed8c4e5ca8d2583e4e9fe62cc7d90fc3d3063d4b.jpg?dateline=1447084542)
![](https://www.miataturbo.net/attachments/engine-performance-56/154414-please-not-another-crankcase-ventilation-thread-80-genny_77aa7ac1ed3b84e26e750a1bf0da62942a9b849a.jpg?dateline=1447084542)
Not much to it. I'm looking, in particular, at the pipe which comes off of one of the rocker covers on each side, and just leads down to the floor. In the first picture, you can see a puddle just below this tube.
"But how does it breathe in fresh air?"
It doesn't. It is an artificial construct to say that it needs to. What it does need is to be able to release the operational blow-by pressure from the crankcase so that the seals are not pushed out.
And that Cummins in the other post is a 5.9. One version of that particular series occasionally had problems with leaky timing cover seals. Its breather tube is on the side on the pushrod cover and hangs down behind the little blue hoses. There is no inlet for "fresh air."