[Thandel]

So I’m planning on using 3 catch cans on my ltg cadi. I’m building an internal pcv valve can which should in theory catch the majority of the nasty crap. I’ll have one larger can for the rear side pcv valve and one for the center top pcv valve.

I’m not concerned about the internal can filling too quickly as that is going to be only dirty nasty junk. I’ll be checking that frequently to get an idea of how quickly it fills. The center top even without the internal doesn’t pull much.

The rear side pcv valve though that can fills up quickly if I’m running wot I thought bad rings but my plugs are all dry, so not that. It’s just the amount of pressure under boost I assume it’s pushing up through the oil valleys.

What I am planning on is getting a 1l baffled tank for the rear side, running a level switch hooked up to an auto drain back to the oil pan. Since it should be mainly oil at that point. I’m thinking just a drain is a bad idea since it could fill up under boost and bottom end pressure could shoot oil up the drain. I could use a check valve but that could inhibit the actual drain if I’m running wot for any long period of time. Thinking about this right now I’m probably not going to fill this thing fast enough that it wouldn’t have time to drain but it’s still a concern.

So I’m thinking an inline fluid pump with a check valve inline. I’m wondering how much pressure the pump would have to push through the drain into the pan, or if the drain would be fine.

Anyone have any input on this? Has anyone attempted this?

[wildchevy]

why would you want to return it to the pan?

[Thandel]

The internal pcv is what is going to catch the majority of the nastiness.

The rear side is going to be mainly oil. To run and not show a vacuum leak or code I need to run the lines as they would be factory. Instead of dumping 1l of oil and adding a liter in it would make more sense to drain that can back to the pan. That can is hooked up to the intake side and fresh air pcv in.. so if it overfills it’s back to square one, Oil in the intake.

From everything I read these motors are very different, engine to engine for oil consumption and oil in the intakes. Mine is one of the heavy consumers apparently. As noted in the main post it’s not rings plugs are dry as a bone.

[geoffchad]

Originally Posted by Thandel

From everything I read these motors are very different, engine to engine

They also appear to be more sensitive to climate, humidity, fuel blend, driving style, etc than other engines - some guys pulled off their IC piping to find a lake in the bottom of the intercoolers. Some find their intake silencer coating in oil while others don't.

At my dealership (Cadillac) I think of all of the 2013+ LTGs that popped pistons, they were nearly all popped in colder months, which may be more likely to condense things where they shouldn't be.

Add in the idea of calcium in the oil and LSPI on top of it and you've got a TON of weird variables with these modern DI engines.

[Thandel]

When I did my front mount I was able to empty the oem stuff and all of it spilled a lot of oil. So far I’ve put all of 200 miles on it just mainly figuring out where when and how much oil is getting pulled through. I’m now at the point of ordering and designing parts for it. Once I have the can set up done I’ll do the downpipe and straight pipe exhaust. Then dyno tune it and that will be it for a while

[Elite Engineering]

Wanted to jump in here and add some info to help.


First, PCV valve does not trap oil, you need a multistage separation system.


Then, if you return what is caught from a truly effective can to the oil pan your greatly reducing engine life and increasing wear as one of the most important functions of the PCV system is to remove the damage and wear causing compounds from the crankcase to reduce wear. If you return this concentrate your guaranteed to cause premature wear and damage.


Here is what our can traps on average from a GDI engine such as the 2.0T in the camaro: This was spun in a centrifuge and then analysis performed:






70% is acids and water
27% is raw fuel (and issue with all GDI engines)
7% is oil saturated with abrasive particulate matter.


So this should NEVER be reintroduced into the engine oil.


You would want to first understand all that the PCV system does as far as functions. The main functions are to remove the damaging compounds from the crankcase before they can settle and mix with the oil causing wear and damage. Only one function is pollution related.


Then you have to understand proper crankcase evacuation, and then effective air/oil separation and containment.


Ask if you want more info, glad to share.

[Thandel]

The internal pcv valve adaptor I’m making will be collecting the dirty vapor. Both other cans are going to be collecting oil pushed back through the oil valleys on full boost not vapor. I have an account on the cadillac forums under the same name check it out.
3 cans is the only truly safe option on the ltg motors
One true separator can for the internal pcv which is where the vapor comes from. One baffled basic can is fine for the top pcv valve you can see it pulls from th same place as the rear side pcv valve. And one large basic baffled for the rear side pcv valve.

The turbo motors have way too much bottom end pressure and pushes straight oil back up the valleys.. this mixes with the vapor from the internal pcv valve and now you gotta drain it with what is essentially 85 percent oil about every 50 miles of hard driving.

There needs to be a check valve on the fresh air in which blocks that from pulling from the can and only allows pull from maf metered air. The rear side pcv out and in are connected together and run to the intake pipe oem which just throws oil into the intake causing problems. Like a lake in the intercooler.

It seems that by utilizing the internal pcv this system would allow the rear pcv out to push mainly oil a.m. I missing something?