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Catch cans and crank pressure

Old 01-18-2015, 05:46 AM
  #31  
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I don't run high boost, only 15 psi but on my car I had issues with oil getting past the turbo seals and it was caused by the factory line from the AOS to the turbo inlet (the one with the little check valve in it) going soft and collapsing when it was hot and under pressure. This was a new part. I replaced it with one straight line of 16mm reinforced silicon hose and now it does not close up and everything is clean.
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Old 01-18-2015, 11:00 AM
  #32  
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A catch can won't really help. The AOS is the cork. Take a soldering iron and open up the hole in the top of it.
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Old 01-18-2015, 12:06 PM
  #33  
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Originally Posted by Tom M'Guinn View Post
Thanks guys. Teddy -- we think alike -- I was going to check the crank pressure but thought I'd clamp a silicon hose over the top of the dipstick tube (with the dipstick removed). Almost seems academic at this point (little elves aren't pushing the stick up under boost) but simple enough to do just to see how much pressure it's seeing. I'll probably put a check valve somewhere just to reduce pressure under boost, though so far it's ok at idle with the factory AOS to J-boost hose. Great input, thanks. I'm sure the old time drag guys did fine with that exhaust venturi, but I'm not quite there yet. While I'm at it I suppose I'll add a catch can too -- trying to sort if I should get the saikou michi can or if I should spend an inordinate amount of time and effort making my own...
I turned a $30 ebay one into a $150 project...but I like the sight level so I can see if there is anything in it. ran a copper tube to the bottom of the inlet and stuffed with SS wool. Seems to work pretty well. No oil residue in the return line to the intake.
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Old 01-18-2015, 12:34 PM
  #34  
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Originally Posted by ekoz View Post
......stuffed with SS wool
That is a REALLY good idea. An ideal catch can will have chambers that force the air to funnel around, which will throw the oil against the walls since it is heavier than the air. It then will drain to the bottom. Good well designed PCV systems are more complicated than many realize.

Your steel wool will help to serve the same purpose.

Note that a catch can does not serve the purpose of reducing blowby, but rather to reduce oil from the intake. Won't help the OP, but will make the catch can more effective at removing oil
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Old 01-18-2015, 03:54 PM
  #35  
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Originally Posted by 67King View Post
A catch can won't really help. The AOS is the cork. Take a soldering iron and open up the hole in the top of it.
Since I'm going down the path, I thought I address both issues -- add another breather via a cam tower plug (with check valve so it only opens when the case has pressure) and a catch can for both the AOS and extra vent, which routes back to the J-pipe. I suppose I could open the AOS up and add a can, but am hesitant to modify the AOS in situ, as I'd rather not have to remove it if it doesn't work as planned (e.g., if the big opening results in more oil leaving the crank all the time)... Can't get started for another week though, so open to all thoughts/experiences on that idea.
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Old 01-18-2015, 04:01 PM
  #36  
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Originally Posted by ekoz View Post
I turned a $30 ebay one into a $150 project...but I like the sight level so I can see if there is anything in it. ran a copper tube to the bottom of the inlet and stuffed with SS wool. Seems to work pretty well. No oil residue in the return line to the intake.
Looks great. Any evidence of the steel wool breaking down and getting fray bits in the intake? I was going to use a stiffer wire mesh, maybe rolled around the center input tube, but steel wool would be a better trap if safe. Here's a nice illustration of how Saikou-Michi does his:

http://www.saikoumichi.com/internal_baffle_design.html
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Old 01-18-2015, 04:05 PM
  #37  
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Harry:

If you take that SS CC concept and then run an additional line from the top of the cam tower with a 1/3 psi check valve to remove the additional positive pressure it should do the trick. I was over at Tom's yesterday and we discussed this quite a bit. I have many cool fittings and valves at work along with high temp Teflon thick wall tubing. We can make something up pretty quickly. Be interesting to see just how much oil vapor is released from the top of the cam tower. Our assumption will be volume. How large of a line do we need to quickly and instantly dump all of the positive pressure? The cam tower plugs will only except around 1/4 NPT, might have to use two. Could have a giant custom plug with hose nipple machined if necessary. I would think 1/2" or -8 should be more than sufficient.
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Old 01-18-2015, 04:06 PM
  #38  
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Tom R U in the air?
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Old 01-18-2015, 04:16 PM
  #39  
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By the way I also have SS mesh in all kinds of sizes at work that we use as oil mist eliminators for old style "wet" vacuum pumps. It would be perfect. For additional ease of mind, I have high flow inline filters just about any micron size we need, all in pretty SS of course!
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Old 01-18-2015, 04:22 PM
  #40  
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Originally Posted by URG8RB8 View Post
By the way I also have SS mesh in all kinds of sizes at work that we use as oil mist eliminators for old style "wet" vacuum pumps. It would be perfect. For additional ease of mind, I have high flow inline filters just about any micron size we need, all in pretty SS of course!
Cool -- may have to talk to you about that. Thanks. I was going to browse McMaster yet again, or home depot
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Old 01-18-2015, 04:57 PM
  #41  
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Make sure and open up the AOS though. Here is a shot of mine using the Lindsey Kit
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Old 01-18-2015, 10:45 PM
  #42  
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Originally Posted by Tom M'Guinn View Post
Looks great. Any evidence of the steel wool breaking down and getting fray bits in the intake? I was going to use a stiffer wire mesh, maybe rolled around the center input tube, but steel wool would be a better trap if safe. Here's a nice illustration of how Saikou-Michi does his: http://www.saikoumichi.com/internal_baffle_design.html
Yeah I thought about the breakdown of the mesh. I used a a couple of ss scrub brushes not ss wool. It's a little heavier material. Not as fine as ss wool. I also put a ss screen vent in the outlet. Like what would be used in a sink faucet to trap anything should it breakdown but I don't think it will. If I were going to do it over, I would probably just buy he saiko and drive on.
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Old 01-18-2015, 10:55 PM
  #43  
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Originally Posted by ekoz View Post
Yeah I thought about the breakdown of the mesh. I used a a couple of ss scrub brushes not ss wool. It's a little heavier material. Not as fine as ss wool. I also put a ss screen vent in the outlet. Like what would be used in a sink faucet to trap anything should it breakdown but I don't think it will. If I were going to do it over, I would probably just buy he saiko and drive on.
I'd get that can in a second, but have some space limitations unless I really move stuff around. I'll take a look at scrub brushes too
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Old 01-20-2015, 04:30 AM
  #44  
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Nah,

Tom, either change your "dip stick" o-rings with new or even better, slightly thicker rings, or do what I've been doing with the same issue. Use Zip Ties every time you pull the dip stick with new Zip Ties. It's just part of the deal, and cheap to boot. No more oil splattering on the hood. All of our motors with 20 year old O- Rings on the top of the dip stick don't SEAL crank pressure, even stock motors. LR sells a rebuild "dip stick" kit for a few bucks. I'm ordering one tomorrow. Costco sells about a "thousand" zip ties for under $20 bucks, I can send you about 10 that will keep you fine for a while.

The comment below somehow is part of my post, but know clearly not my statement towards remedy. G

Typically excessive crankcase pressure comes from blow by the rings. You might want to perform a compression or a leak down check. Rigging a catch can may only be putting a bandaid on the real issue.

I run 22psi and while my adrenaline is rushing....my dipstick remains limp.[/QUOTE]
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Old 01-20-2015, 06:21 PM
  #45  
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Originally Posted by George D View Post
Nah,

Tom, either change your "dip stick" o-rings with new or even better, slightly thicker rings, or do what I've been doing with the same issue. Use Zip Ties every time you pull the dip stick with new Zip Ties. It's just part of the deal, and cheap to boot. No more oil splattering on the hood. All of our motors with 20 year old O- Rings on the top of the dip stick don't SEAL crank pressure, even stock motors. LR sells a rebuild "dip stick" kit for a few bucks. I'm ordering one tomorrow. Costco sells about a "thousand" zip ties for under $20 bucks, I can send you about 10 that will keep you fine for a while.

The comment below somehow is part of my post, but know clearly not my statement towards remedy. G

Typically excessive crankcase pressure comes from blow by the rings. You might want to perform a compression or a leak down check. Rigging a catch can may only be putting a bandaid on the real issue.

I run 22psi and while my adrenaline is rushing....my dipstick remains limp.
[/QUOTE]

Thanks, will make sure the stick is sealed and secure but need to increase the venting capacity if the crankcase too. Otherwise that pressure will find some more sinister way out of the crankcase (oil pan gasket, rear seal, oil thermostat o-rings, etc)...
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