Catch cans and crank pressure
#61
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After mulling a bunch of options, it finally dawned on me to tee into the vent line going from the AOS to turbo mount. I looked and confirmed the hole in the AOS is much bigger there, and I can put a check valve before the catch can so that port will only vent when the crankcase is under pressure. That's mt latest plan anyway...
Turbo mount is vented and helps drain the oil from the turbo. You don't want to add any pressure to negate it.
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#63
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Increasing diameter increases flow, but reduces pressure. Restrictions create pressure.
#64
#66
What effect would connecting the turbo mount vent directly to a vacuum source instead of the side port on the AOS have? If that is just a vent, no liquid oil, then connecting it to the intake manifold with a check valve inline will assist with draining the oil through the turbo....?
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#68
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Thanks, I hear you. The approach I have in mind would only decrease pressure in mount/drain -- never increase it. The extra line would have a check valve, so the pressure in the drain/mount would be identical to stock unless/until the crankcase has positive pressure. When the crankcase has positive pressure, the check valve will open and reduce the pressure in the crankcase (and therefore the pressure in the turbo mount/drain). Or am I missing something?
#69
If the pipe between the turbo mount and the AOS is a "drain" pipe, then we want vacuum in it. By the time some check valve added in the system opens it means there will be pressure in the system whereas we only want vacuum.
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Looks like it is made of buna rubber that doesn't like synthetic oils.
Very simple seal so replacement should not be a problem.
#71
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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.
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.
On the other hand it could alleviate the problem with the cam tower gaskets.
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Thanks for the link Ted, nice and simple adaptor! I assume you are venting your cam tower all ready since you are using this fitting. Have you experienced any of the issues mentioned above? How much oil blow by is coming from the cam tower. I would assume not that much, but you know what that gets you. Which check valve did you select for this line?
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I've bought this kind of M18x1.5 adapter to fit my pcv and couldn't screw it full...
#75
Thanks for the link Ted, nice and simple adaptor! I assume you are venting your cam tower all ready since you are using this fitting. Have you experienced any of the issues mentioned above? How much oil blow by is coming from the cam tower. I would assume not that much, but you know what that gets you. Which check valve did you select for this line?
Here is where I got my check valves from.
http://www.usplastic.com/catalog/def...arentcatid=870
I used brass because once I found a solution I was going to use copper tubing with some compression fitting to make a custom venting system. Some of the brass valves have a 1/3 PSI cracking pressure. Maybe using a couple cam ports with these low PSI cracking valves will work? I don't think the cam ports are a good source for pulling vacuum on the crankcase, they maybe better at relieving pressure though. Once the crankcase pressure got over 1 PSI these valves should pop open and flow out cam tower port and into a catch can. I'm concerned about what will flow out of the ports though. I would assume oily vapors but I don't know for sure.