TLewis4095

iTrader: (10)

Heres the problem with hoses hanging near the ground & plugging your vacuum source. When at speed, one hose will develop negative pressure, and the other positive as the hose has a venturi effect when air is moving past it. What happens then is you are sucking up dirt, sand, water, etc. directly into your valve cover & into the motor internals. I suspect they have no filter on them, correct? Also, if you are not pulling metered vacuum at idle & low RPM's the harmfull vapors that are in your crankcase cannot be pulled totally out...only pressure vents so all the unburnt fuel, caustic gasses from blow-by, & moisture will re-condense in your crankcase after the motor cools & contaminate the oil as well as corode internal parts (look at the links in another thread on bearings & see the damage just the unfiltered dust causes). A proper PCV system needs a fresh air source that is filtered, (on the stock OEM setup it is drawn from in front of the throttle body & the main air filer cleans the air pulled) and a vacum source that is metered & valved, such as the PCV valve on a LS1 or the fixed orfice & baffle system in the vally cover of the LS6 & LS2/3/7 design. The problem with the OEM systems on our vettes is it allows oil vapors to be pulled into the intake & robs power & contributes to detonation. The only proper way to correct this w/out sacrificing your engine to premature wear (I have seen motor come in that look like dirt was poured right into the crankcase & no internal part not showing advanced wear & failure from the hoses dangling unfiltered to the ground. Those that have this setup just have to look closly at your oil the next time you change it to see how dark it now comes out compared to when you had the stock system in place) is to modify the system to remove as much of the oil & harmful vapors from the PCV lines before the mist is pulled into the intake. So the most effective mod for NA motors is to add the proper catch can system AND a PCV valve inline to control the amount of vacuum pulled & prevent back-flow of the vapors.


The catch can must be of a material that disipates heat effectively, and that eliminates plastic. Auminum or steel are the 2 best. 2nd, the can must be baffeled in such a way as it disperses the vapors to make contact with as much of the cooler outer surface of the can to allow the vapors & oil to condense into droplets that are collected in the bottom of the can. Now 2 forms of oil come through the system....a mist from the fast movong internals in the engine which is pretty easy to trap, and the vapors from the high heat which need the cooler surface area to condense.
So the can has to be large enough to be effective & most I see in use are far to small, allthough there are several good ones on the market. Then the outlet of the can must be located as far up & away from the inlet to prevent vapors from being pulled through before having a chance to cool & condense. You then need a PCV valve to control the amount of vacuum.






(this setup uses a perforated down tube to disperse the vapors as completly as possible for contact on the cooler surface & is a 1 qt capacity)


If you have a stroker, big cube build, or run at extended high RPMs you should also add the filtered breather as some have mentioned above (easiest is as an oil fill cap mod) and this will allow a good volume of filtered fresh air in at low RPMs and allow venting of crancase pressure at high RPMs. On a FI application it gets just a little more complicated but the design is very similar.

Shown below is on a Magnacharger application.




So what you have accomplished is a near total elimination of any oil getting into the intake, proper ventalation & breathing, and not subjecting your babies motor to a slow horrible premature death from unfiltered ventalation.

Hope this helps

Viper

iTrader: (6)

What about using a second catch can on the fresh air line? I know after road racing and sustained high rpms (not 1/4 mile or street driving) that the TB line from the passenger valve cover can actually pull oil in instead of fresh air to the valve cover. Thoughts?

TLewis4095

iTrader: (10)

That's common with extended high RPM running due to the excessive crankcase pressure & yes, running a can on the inlet side would work. In race applications the off-road breather mod will allow the venting of them w/out pushing oil back up the fresh air intake. On some of the bigger FI builds two cans like you mention are used w/the breather on the intake catch can. Good idea!!

Viper

iTrader: (6)

"If you have a stroker, big cube build, or run at extended high RPMs you should also add the filtered breather as some have mentioned above (easiest is as an oil fill cap mod) and this will allow a good volume of filtered fresh air in at low RPMs and allow venting of crancase pressure at high RPMs"

Are you saying to use the catch can, PCV valve AND a breather on the oil cap?

And with the PCV valve, do you recommend before or after the catch can?

I've got the AMW and it shows hose from PCV to top of catch can, then line from side of catch can to intake.

BlackDuk98

iTrader: (34)

Thats the way that I have seen most have it set up on the boards, but it looks like the second pic shows the pcv after the catch can. I have the same question.

Also, I read somewhere that someone switched hoses from top to side so that the one going to the front of the intake actually is at the top connection and the one comeing from the valve cover is one the side. The explination was because the side hose will still suck up the falling oil vapor etc and defeat the purpose of the catch can. Anything to this????

thanks

snake charmer

iTrader: (118)

i just blocked off the y that goes to the intake and lest the hose going from the back of both valve covers connected . then put a rubber nipple over the front passenger side valve cover , put a 3/8 plug in the tb and finally put a nice big chrome breather where the oil cap goes . car runs fine and has less of a mess . ran the engine hard just took the tb off and no oil whatsoever on the back of the tb or intake .
feeding all that oil , heat , bad air back into the car can not be healty to the engine .
nice looking catch can !

TLewis4095

iTrader: (10)

This a quick sketch of the can. As you can see if it was swapped the can would not work. You need the vapors to be dispersed as evenly as possible to contact as much cooler surface area so the vapors can condense & form droplets that collect in the bottom. Most cans that are metal will work well at removing the oil mist, which is where most of the oil contamination comes from, but this design does a great job of condensing the vapors as well...and the 1qt size gives more area to cool the vapors as the air is pulled through it. As you can see the highest point off the can is the side fitting. I'll cut one apart from the next batch so we can display it & get some good pics.

BlackDuk98

iTrader: (34)

Thanks for the pic and info on the subject. Cleared everything up for me. From what I have seen on the boards and other sites, this is the nicest catch can that I have seen. Gunna have to get one when $$ becomes available, lol

thanks

Viper

iTrader: (6)

TLewis4095:

"If you have a stroker, big cube build, or run at extended high RPMs you should also add the filtered breather as some have mentioned above (easiest is as an oil fill cap mod) and this will allow a good volume of filtered fresh air in at low RPMs and allow venting of crancase pressure at high RPMs"

Are you saying to use the catch can, PCV valve AND a breather on the oil cap?

TLewis4095

iTrader: (10)

Yes with a stroker motor due to the increase of crankcase pressure at high RPMs.

There are some nicer looking cans out there, but I have not seen a more functional one.

fortmyerspolice

iTrader: (7)

So how much for the catch can without the breather filter?

TLewis4095

iTrader: (10)

$69, plus $15 S&H to the lower 48.

Can powder coat for $35 most colors. Comes as the kit shown but w/out the breather.

BrianC98Z28

iTrader: (11)

still havent seen pictures of how its setup with an LS6 Pcv setup with the valley cover and stuff.

TLewis4095

iTrader: (10)

Very simple. On the LS6 valley cover there is a fixed orfice built in to control the amount of vacum & it has a built in baffle. You just run the can inline between the intake vacum source & the vally cover. No need to have a PCV valve.

Viper

iTrader: (6)

The 02 LS6 does not have the baffle. The 04 LS6 and LS2 do have the baffle.

TLewis4095

iTrader: (10)

Correct. The install is the same with either version though.

Nightrydass

origionally the hose that gets connected to the top of the can was running to the intake, right? You're just cutting that hose and inserting the origional hose into the top of the can and using the provided hose to connect back to the intake. right?

if you were to trace that origional hose it would run to the valley cover.


*btw - i have the LS6 intake system*

TLewis4095

iTrader: (10)

On our can the fitting on the top side goes to the intake/vacuum source & the top fitting goes to either the valley cover on a LS6, or the passenger side valve cover on the LS1 since the flow needs to go through the top center fitting, down the perforated down tube where the vapors are dispersed so they contact as much of the inner surface as possible to condense, and then out the top side to the vacuum source.

Nightrydass

ok, it is hard to judge from your pic and my car is still covered up.

It is just one hose tho right? All you're doing is putting the can in between it?
in other words: W/O the can; the hose from the passanger side valley cover goes right into the intake vacume source, correct? I'm unhooking that, cutting the hose and installing the hose from the passanger side valley cover to the top connection and using your supplied hose to connect the top side connection to the intake vaccume source. Correct?

Viper

iTrader: (6)

If you check out this:

http://www.ls1howto.com/index.php?article=18

You'll see the hose in the second to last picture:



So yes, the can just goes in between that hose.