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I bought a catch can a while back and got around to installing it today. Had to remove the throttle body to get access to the U shaped hose I needed to remove. Noticed a puddle of Mobile 1 on the floor of the intake and cleaned it up. Guess I needed the catch can. All stock motor.
put on the new (used) to me red coil covers too. Nice accent with the red calipers and red striped wheels.
What does a cat can do and what does it mean if it does have oil or if it is even full every time you change your oil does that mean you're blowing oil somewhere or your rings are bad. Or is it just normal and it keeps the oil out of the fuel air mixture
The catch can helps keep the oil coming up from the valley cover going into your manifold. Does it catch all oil no but a good amount. The vacuum line on the manifold that goes to the valley pan has quite a bit of vacuum on though the valley pan is baffled some oil does get by an would then go into manifold.
Are there any catch can designs for the Corvette that drain back into the sump so that you never have to worry about draining it? Just curious.
I don't think that would work. If you tapped a line into the oil pan, the intake would suck oil up like a straw. You'd need some kind of check valve to keep the oil in the pan from getting sucked into the intake when there's a lot of vacuum.
Anyway, you don't have to drain it all that often. As somebody already noted, you only have to drain it about once every oil change.
Farm,
Do you have a pic of the bracket and spacer you used to mount the catch can? Curious how that went for you.
I put similar on my LS2 but had to get a different bracket from the supplier that had a more acute angle to it in order to get things to fit and allow clearance to unscrew the can.
Overall, happy with it now, no more oil in the intake! Now monitoring "catch rate."
Vacuum line from the intake manifold side of the throttle body pulls in the crankcase fumes. There is always a vacuum there until you get into boost.
Those crankcase fumes come out of the barb on the valley cover and through the catch can before being sucked into the intake manifold.
Because we are sucking fumes from the crankcase, we need a place that allows clean outside air to inter the crankcase (are you still with me ?)
Well, that clean air inters the crankcase through the filter that's attached to the passenger side valve cover (the same place you would add oil to the engine when changing oil).
At real high boost during full throttle operation, [if] cylinder pressure enters the crankcase, this same filter will allow it to escape out into the atmosphere (saving the crankshaft rear main seal).
Or ... if you did not want to modify the valve cover with a breather to let in the clean filtered air into the crankcase ... you could install a line like in the diagram below:
Or ... if you did not want to modify the valve cover with a breather to let in the clean filtered air into the crankcase ... you could install a line like in the diagram below:
Air flow is wrong on the blue line.
Green line is the vacuum back into the intake at less than WOT, and blue line is the vacuum back into the intake at WOT when the intake manifold goes to zero vacuum instead.
Also, although both the valley cover (brown) and valve cover (blue) both have oil baffles, the valve cover is higher in the motor, and is the clean side of the system.
Hence blow by will always have the engine block having pressure that is needs to vent, and its the dirty and and clean side that are under vacuums (depending if wot or not), that is pulling the pressure out of the engine block to keep the oil cleaner as it burning off the impurities (gas from the blow by, and humidity out of the air that ends up in the oil that is being burnt out as the oil comes up to temp).
So really, the stock oil baffles do work well for normal RPM ranges as the block pressures from piston blow by, and it during full tilt boggy of higher RPMs that you get the extra oil through the stock valley and valve covers baffles that you are wanting to catch. At WOT, valve cover, and as you come off the throttle, back at the valley cover.
I bring this up, since the clean side at high rpms during WOT (when the valley point does not have vacuum), its not that clean, and you want to be catching the excess oil out of the valve cover port so the PCV excess oil is not making it way back into the intake manifold that way as well. Hence if you clean the TB and find a lot of oil on the front of the TB vain and entry tunnel section, it's coming from the clean side port, which is in front of the TB.
Sure it's right ... Since you are pulling dirty (oil fumes) from the crankcase via the valley cover barb and through the catch can and then into the vacuum port of the intake manifold, you then need a source of filtered clean air to replace 'cleaned' crankase air that has been cleaned through the catch can and sucked into the intake manifold.
That clean outside air needs to come from someplace ... in the case of the last photo I posted above, that clean fresh air comes from that large rubber tube that attaches to the front of the throttle body.
This is basically the same way as the factory does it (obviously, without the added catch can installed).
The valley pan tube actually has a .100 restrictor in it to reduce the flow through the tube. The restrictor tube reduces the cfm from say 20 cfm (3/8 tube) down to like 3 cfm (.100 hole) assuming like 18 inches of vacuum. The passenger side valve cover is a 3/8 tube no restrictions. On the dry sump LS7 the drivers valve cover is also a clean air intake via the dry sump tank via the air bridge in the front. You can not run the dirty side PCV through the valve cover as there is no restrictor (too much air flow given the amount of engine vacuum). The restrictor tube reduces the cfm from say 20 cfm (3/8 tube) down to like 3 cfm (.100 hole) assuming like 18 inches of vacuum. It is fine for fresh air intake on the passenger side. That being said on the LSX 454 engine the back valve cover has a tube with a restrictor in it (just like one in phot below) and also uses the valley pan - that is right 2 dirty side intakes still has the fresh air coming in from the passenger side valve cover or you can run a breather. The reason for the dirty intake in the back drivers side cover is it provides more flow and on the other side of the motor to get bad gasses from the back. I learned this reading the LSX instructions on installation they have a 1/2 page on the PCV system. My guess for the two ports (valley pan and valve cover) is the engine is big and the other it has low vacuum due to the big cam and thus less suction. Here is a photo of the restrictor in the tube.
Put on a catch can
