hottscennessey said:
We can preach and preach to these guys Hottscennessey, but they wont' listen untill it happens to them. :icon_conf :nono:
Catch can
- Thread starter AGlobalThreat
- Start date
We can preach and preach to these guys Hottscennessey, but they wont' listen untill it happens to them. :icon_conf :nono:
Rich said:
When each piston moves up, it sucks in air through your vent thats what 1/2" total diameter?
When each piston moves down, it has to push the air in the crank case back out through that 1/2" vent.
You're trying to stuff 10lbs of sh!t in a 5lb bag. If you have vacuum on said system, you no longer have any pressure or *chance* of pressure in the crank case.
Not to mention, every race car that I have ever worked on - from Indy Cars to Nascars to Sprint Cars to Midgets - have some sort of vacuum system to draw vacuum on the crank case. Its HP dyno proven. :icon_bigg
MDCmotorsports said:
Yes, that's what I thought, I'm sorry to say but you're wrong.
Pistons moving up and down don't create crank case pressure. When one piston goes up, another goes down. Or in other words, the volume of the crank case always is the same. If it wouldn't the crank wouldn't be in balance. Air is only moving around, no pressure is created by this.
Crank case pressure is created by combustion gases which leak past the piston rings, there always is some leakage, there will never be a 100% seal.
The main reason to vent the case is not pressure relieve but to get rid of these gases as they are harmful to the internals. They contain hydrocarbons, carbon dioxide and watervapor which are corrosive and can turn oil into sludge.
If you have that much pressure in your crank case to blow out seals then you simply have too much gases leaking by your rings, in other words you have blow by.
Check the static compression of an engine which is blowing seals and most probably you have found the reason why it does that.
Rich said:
interesting, however, if outside air is getting in (lets say its 80 degrees), then the air will instantly be heated because of the crankcase temp. the same volume of air 20 degrees hotter can not escape through a hole that the colder air can enter....... just a thought
I'd add PCV is not there just for "classic" blowby. Crankcase venting is also required because of the compression stroke. PCV was developed as an emissions system with the original intent to scavenge raw HC lost past unloaded rings before combustion occurs and then send it back to the intake for burning. Everything else aside that's still it's purpose today.
Have too much pressure? Fix the motor or increase the flow ability of the system. That could include vacuum but it doesn't have to. As long as the system's conductance can handle the flow using volume alone there is no need for vacuum. It won't do the oil, engine, or environment any good but neither will it blow out seals. After all every old car ran a draft tube and there wasn't much vacuum on them.
I'm staying out of the catch can thing. I long ago gave up on most people getting it right. It's getting better though. There may be some hope yet.
Have too much pressure? Fix the motor or increase the flow ability of the system. That could include vacuum but it doesn't have to. As long as the system's conductance can handle the flow using volume alone there is no need for vacuum. It won't do the oil, engine, or environment any good but neither will it blow out seals. After all every old car ran a draft tube and there wasn't much vacuum on them.
I'm staying out of the catch can thing. I long ago gave up on most people getting it right. It's getting better though. There may be some hope yet.
Ok, i am so very confused with this topic. Mainly because i haven't seen any diagrams of these systems. It would be awesome if some had diagrams. Anyway this is what i am understanding so far. Please do not hesitate to correct me or throw anything else in.
I have a catch can and want to use it to get rid of the oil going through my intake system. from what i understand the PCV is there to release the blow by exhaust gases and not let anything back in. The PCV is then connected by tubing to the intake which has a constant flow of air. This does 2 things, a) it creates a vacuum in the crankcase and b) the routing allows the hydrocarbons to flow back into the engine to fully combust again.
Now, because of this vacuum in the crankcase, some oil ends up being sucked through with the gases into the intake. So the point of the catch can is to go in between the PCV and the intake and collect the oil and allow the gases to continue through.
-Where exactly is the tubing connecting to? I thought it goes to the intake manifold but people are talking about oil condensing in the intercooler?
-I have a 1jz and there is tubing running from the valve cover exaust side to the turbo intake y-pipe. and also some tubing from the intake side as well. What are these tubes for???
thanks in advance guys.
I have a catch can and want to use it to get rid of the oil going through my intake system. from what i understand the PCV is there to release the blow by exhaust gases and not let anything back in. The PCV is then connected by tubing to the intake which has a constant flow of air. This does 2 things, a) it creates a vacuum in the crankcase and b) the routing allows the hydrocarbons to flow back into the engine to fully combust again.
Now, because of this vacuum in the crankcase, some oil ends up being sucked through with the gases into the intake. So the point of the catch can is to go in between the PCV and the intake and collect the oil and allow the gases to continue through.
-Where exactly is the tubing connecting to? I thought it goes to the intake manifold but people are talking about oil condensing in the intercooler?
-I have a 1jz and there is tubing running from the valve cover exaust side to the turbo intake y-pipe. and also some tubing from the intake side as well. What are these tubes for???
thanks in advance guys.
the oil in IC is what the catch can hopefully will help prevent or minimalize. i dont have much time to answer sorry i'll come back later! 
my PCV Is going to be stock, although from the exhaust side that usually goes to the intake i am sending that to the catch can and the other part of the catch can back to the intake so the tank is right theree =D
(this is for my 2jz but it pretty much looks the same on a 1jz)
my PCV Is going to be stock, although from the exhaust side that usually goes to the intake i am sending that to the catch can and the other part of the catch can back to the intake so the tank is right theree =D
(this is for my 2jz but it pretty much looks the same on a 1jz)
ok i tried to draw at least. valve covers in the middle, intake manifold on the right, catch can in the upper left and turbo/intake beneath the catch can. the red lines represent where lines need to be run, except between the valve covers, that ones already there. the spot where the pcv valve ran from the intake manifold also needs to be blocked off now because you don't need it anymore. the intake provides the vacuum for the system. i just wasn't sure what catch can to buy...
i was also toying with the idea of running a tee fitting from the 2 inside ports on the valve covers to 1 line to the catch can and having the outside ports welded flush. anyone think it would work or would there be restrictions from the inside of valve covers (not sure if there is anything in the way to prevent good enough flow)?
they were the original sources of vaccum. the line on the exhaust side was run to the intake piping before it went into the turbos so there was vacuum there. the line on the intake side ran through the pcv valve to the intake manifold so only vacuum could come from the intake manifold, not boost.
just a few questions on this setup. i assume the second line running from the intake pipe goes to the intake manifold. is that line really neccessary?tsuper92 said:this is how i set mine up
i was also toying with the idea of running a tee fitting from the 2 inside ports on the valve covers to 1 line to the catch can and having the outside ports welded flush. anyone think it would work or would there be restrictions from the inside of valve covers (not sure if there is anything in the way to prevent good enough flow)?
Kosh said:
they were the original sources of vaccum. the line on the exhaust side was run to the intake piping before it went into the turbos so there was vacuum there. the line on the intake side ran through the pcv valve to the intake manifold so only vacuum could come from the intake manifold, not boost.
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Kosh said:
- Tubing is connected to the intake pipe before the turbo, there is always vacuum there. If you connect it to the intake manifold, then you need to put a one way valve in between. Downside of this is you won't have any vacuum anymore once there's boost.
- These tubes on the stock set-up are the pcv; one to the pre-turbo side, one to the intake manifold with a one way valve in between. The first one will suck in oil fumes to the pre-turbo side which will condensate in the IC and also crap up the turbo(s). To prevent that put a catch can in between like in the two pics in post #6.
Yeah, the best place for a catch can is between the valve cover, and intake piping. This prevents oil from going through your turbo, and intercooler. Placing it between yout valve cover, and intake manifold really just sstops it from going into the intake manifold, which doesn't really matter, as it will go into the cylinders and be combusted.
jizake1jz said:
ok so if i set it up like this, i will be getting rid of the line to the intake manifold all together correct. So then i will not need to worry about the whole upgrading the check valve right? what about the crank case? Where does that draw vaccum from and should i be worrying about that too?
EDIT: Also, i bought the CC off of driftmotion. It has 3 fitttings on it, 2 on top and one on the bottom. Which go where? do i use the bottom one for vacuum and the top 2 to go one to each valve cover? Or is the bottom one just for draining the can? thanks.
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Kosh said:
Hook it up like that and cap off the intake where the tube used to be and you're good to go. Mount the catch can in a cool place so as much oil condensates as possible. For an even better effect, baffle the catch can internally to get a bigger surface for condentsation.
The crank case is vented through the cam covers ;-), that IS the pcv route.
OneJSupra said:
Again, bad idea. That filter needs to be removed an another hose going from the (previous) filter nipple to the turbo inlet needs to be added.
Kosh said:
MDCmotorsports said:
wait why would he need to get a new pcv valve and hose? isn't he just blocking off the intake manifold and then running lines to the catch can from the valve covers. theres no need for the intake manifold to valve cover line anymore so definately no need for pcv valve at all.