More Oil Catch Can Contents
#81
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Update first track day and the slash cut was sucking oil out of the catch can and out the tailpipe after left hand corners. Didn’t do that for any of the street driving I was doing prior.
http://www.youtube.com/watch?v=5hsQYiIHiq0
I’m thinking some sort of check valve in the return line and cap off the OEM PCV breather port.
Bob
http://www.youtube.com/watch?v=5hsQYiIHiq0
I’m thinking some sort of check valve in the return line and cap off the OEM PCV breather port.
Bob
Sorry no comment on the issue though =P
#82
Moderator
![](/mt2011/images_td/ranks/supporter1.gif)
![](/mt2011/images_td/ranks/moderator.png)
iTrader: (12)
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 20,884
Total Cats: 3,075
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Do you think a larger diameter hose from the VC to the can might slow the velocity enough to cause it to pull less oil in the vapor? How about a larger volume of air in the catch can? That might help to let it settle as well.
#84
Elite Member
Thread Starter
iTrader: (2)
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,141
Total Cats: 230
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Possible that the cylinder head is filling up with oil on a long straight under high boost (and not letting the oil flow back down into the crankcase) and then the immediate left turn has some serious sloshing of oil to the passenger's side valve cover?
#85
Elite Member
iTrader: (2)
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,682
Total Cats: 130
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I ordered up the moroso slash cut pipe and check valve from Summit.
My plan is as follows:
Weld shut PCV port
Enlarge "tiny hole" in VC baffle and possibly make another hole for good flow
Cut off and weld shut breather
Weld in a -12 male fitting on top of the VC, near the end of the baffle chamber
Connect VC to a sealed, non-VTA, baffled peterson catch can with a -12 and -10 fitting on it
Connect catch can to slash cut with some SS braid line and a hard line adapter. The slash cut is 5/8 so -10 hose will fit.
My plan is as follows:
Weld shut PCV port
Enlarge "tiny hole" in VC baffle and possibly make another hole for good flow
Cut off and weld shut breather
Weld in a -12 male fitting on top of the VC, near the end of the baffle chamber
Connect VC to a sealed, non-VTA, baffled peterson catch can with a -12 and -10 fitting on it
Connect catch can to slash cut with some SS braid line and a hard line adapter. The slash cut is 5/8 so -10 hose will fit.
I don't remember- do you still have the baffles in place?
#87
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
My next attempt I took vent line off the passenger side. I also found a PCV valve that seems to work perfect as a check valve in my -10 drain back hose to the bottom of the pan. It was less than $2. testing shows water will gravity feed freely down it and wont come back up either sucking or blowing.
I looked at a diagram on the Mann-Hummel site for the Provent 200 and they recommend a check valve.
http://www.mann-hummel.com/industria...BVFLGOcGNM.pdf
I found a part number for it but it was like $60 just for the valve. I can’t believe it is any more sophisticated than the $2 part.
Bob
#88
Elite Member
iTrader: (2)
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,682
Total Cats: 130
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I do not. I welded the pcv valve port shut because I had the middle-to-exhaust baffle connecting hole reamed out and am using a single -12 fitting which goes to the exhaust. To me, it looked like the PCV baffle would not be nearly as effective as the long middle-to-exhaust baffle route. As you mentioned though, the VVT baffles are different than the non-VVT baffle system.
#89
Moderator
![](/mt2011/images_td/ranks/supporter1.gif)
![](/mt2011/images_td/ranks/moderator.png)
iTrader: (12)
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 20,884
Total Cats: 3,075
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Maybe move the VC outlet to the top of the VC instead of the side like the RB26 and/or use two outlets like it does? I assume it was designed for higher RPM and stronger G forces than our design.
![](http://image.turbomagazine.com/f/27648613/turp_0603_08_o+1996_nissan_240_sx_skyline_engine+chrome_valve_cover.jpg)
#92
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Your motor with the stock internals, did it have the stock pump too?
Have you measured the crank case pressure?
#94
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I haven’t measured crank case pressure but it can't be very high because it is vented well and vented to a slash cut in the exhaust that seems to do real well at sucking the contents of the catch can out the tailpipe when it fills up.
Compression and leak down seem fine and it makes lots of power and torque with no other evidence of mechanical health issues around cylinders pistons combustion chambers or valves.
Bob
#95
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Those of us at the Club Trials think the smoke from Bob's car was actually solid rocket fuel aiding in acceleration.
I'm telling everyone I got FTD since Bob doesn't count (he beat me and everyone else by almost 5 seconds on that 60 second track).
On the oil, I think the check valve in the drain back to the pan will fix this. The stock MSM system has a similar flaw where oil will be drawn out of the pan on high G left handers under throttle. I plugged my drain and scrapped the whole OEM system for a simple can and breather.
-hyde
![](https://www.miataturbo.net/images/smilies/bowrofl.gif)
On the oil, I think the check valve in the drain back to the pan will fix this. The stock MSM system has a similar flaw where oil will be drawn out of the pan on high G left handers under throttle. I plugged my drain and scrapped the whole OEM system for a simple can and breather.
-hyde
#96
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Those of us at the Club Trials think the smoke from Bob's car was actually solid rocket fuel aiding in acceleration.
I'm telling everyone I got FTD since Bob doesn't count (he beat me and everyone else by almost 5 seconds on that 60 second track).
On the oil, I think the check valve in the drain back to the pan will fix this. The stock MSM system has a similar flaw where oil will be drawn out of the pan on high G left handers under throttle. I plugged my drain and scrapped the whole OEM system for a simple can and breather.
-hyde
![](https://www.miataturbo.net/images/smilies/bowrofl.gif)
On the oil, I think the check valve in the drain back to the pan will fix this. The stock MSM system has a similar flaw where oil will be drawn out of the pan on high G left handers under throttle. I plugged my drain and scrapped the whole OEM system for a simple can and breather.
-hyde
A combination of acceleration and left cornering simultaniously seems to be the puke inducer. Probably some hard on/off throttle aids in the sloshing wave action in the oil too.
Bob
#99
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I've had similar problems without the drain back to the pan hooked up however. Filled up the catch can before but now I have the exhaust sucking on it as well so instead of overflowing in my engine compartment it gets sucked out the tailpipe and makes glorious clouds of smoke. I think it must be the intake side valve cover vent as the major contributor. The intake side vent will be blocked off for next Thursday at Pacific. I have all sorts of caps and stuff to reconfigure things if it doesn’t work.
A combination of acceleration and left cornering simultaniously seems to be the puke inducer. Probably some hard on/off throttle aids in the sloshing wave action in the oil too.
Bob
A combination of acceleration and left cornering simultaniously seems to be the puke inducer. Probably some hard on/off throttle aids in the sloshing wave action in the oil too.
Bob
On another note to simplify for my simple mind, you are suggesting people ditch the VTA filters/breathers and in place put a (say -10an size) hose in its place even if they dont have a return to sump line from the catch can?
Think there is any real benefit with going with this type of EVAC fitting with the Venturi style tip? Only $2 more then Summit kit. I have heard that Venturi tips draw vacuum better?
Vibrant EVAC Kit
#100
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
So in your video you posted with the puffs of smoke, that is all simply from pulling a strong vacuum on the crankcase and then basically burning it?!?!
On another note to simplify for my simple mind, you are suggesting people ditch the VTA filters/breathers and in place put a (say -10an size) hose in its place even if they dont have a return to sump line from the catch can?
Think there is any real benefit with going with this type of EVAC fitting with the Venturi style tip? Only $2 more then Summit kit. I have heard that Venturi tips draw vacuum better?
Vibrant EVAC Kit
On another note to simplify for my simple mind, you are suggesting people ditch the VTA filters/breathers and in place put a (say -10an size) hose in its place even if they dont have a return to sump line from the catch can?
Think there is any real benefit with going with this type of EVAC fitting with the Venturi style tip? Only $2 more then Summit kit. I have heard that Venturi tips draw vacuum better?
Vibrant EVAC Kit
I have an update though.
I removed the valve cover vent from the intake side (The OEM PCV port), just blocked it off still have the exhaust side valve cover breather and -10 vent port in the side of the block. I also found a PCV valve that works perfect in my -10 return line to the bottom of the pan. No more puking lots of oil into the catch can at all.
I am fairly confident that I have learned that using the OEM PCV port as a vent source doesn’t work well. Oil must pool up in the aft right corner of the valve cover when you have high cornering G’s, Hard acceleration, and some on/off throttle it will puke oil out. You can drive around hard on street tires all day and not have an issue. Put sticky tires on it and flog it on the track with some hard left hand turns and it is a different story.
The vent on the exhaust side is baffled with it’s opening right in the center of the valve cover and the oil doesn’t slosh into it.
Bob