UPDATE: Lots of oil getting through the AOS! Read my posts for info!

It was brought up in another thread that a bit too much oil can get into the intake system. I know my car ('07 V8V) has an Air-Oil Separator (AOS), and I'd imagine all the V8's do, and wouldn't be surprised if the V12's do, too. I did a DIY writeup a while back for replacing it (great info for those that haven't seen it). I haven't checked my intake manifold to see if oil is getting through, but I'm willing to bet that there are some real improvements to be made to the AOS recirc.

First off, here's the DIY for the AOS:
https://www.6speedonline.com/forums/...separator.html

Here is the location of the AOS in the engine bay:


You can see a rubber line underneath the plastic line immediately above the red circle. This rubber line is the hose that takes vented air and recirculates it back into the intake. In theory, that air should be oil free, but that isn't necessarily the case. Under certain circumstances (for example, spirited driving and hard cornering), oil will still get through the AOS and into the intake manifold.

To fix this, we need an oil catch can in that rubber hose. So instead of this:

AOS -> Intake Manifold

We need this:

AOS -> Oil Catch Can -> Intake Manifold

I've got way too much going on this month, but I'd be happy to do some testing and a DIY writeup next month if nobody has done it by then.

What are the benefits? A cleaner burn since oil isn't getting into the air-fuel mixture. And since your air-fuel mixture is cleaner, you're also getting better performance from your engine. Oil as a contaminant effectively lowers your octane rating. Our cars are EXTREMELY sensitive to fuel quality, and I'm willing to bet oil in the air-fuel mixture does have an effect on the way our engines run.

Of course, I'm not an automotive engineer, so take all this with a grain of salt. I did, however, stay at a Holiday Inn Express last night.

 

 

 

I went ahead poked my car with a stick to see what was going on with the AOS. I pulled the main intake hose off the manifold to see how the throttle body looked. LOTS of buildup! However, the intake hose itself wasn't dirty. Just to be sure, I checked each of the rubber hoses going into that main intake hose. All clean. That means the buildup is caused by something post-throttle body.

So I pulled off the plastic hose going from the PCV (positive crankcase ventilation, although I usually mess up and say pressure control valve) assembly to the intake manifold. There was standing oil!!





As Irish said in his comment above, the PCV is fed by the AOS. Below is a pic of the AOS and the hose leading out of it, which wraps around and goes to the PCV. I pulled my AOS (literally a 10 second job ) to check this hose... FULL of oil! So the pic below is where the oil catch can will be going! I think all this oil is causing the nasty buildup in the throttle body and intake manifold, and fixing this will lead to some awesome results.

 

BTW, I've got a buddy that does fabrication that is going to make a custom mounting bracket for the catch can. Once I get the catch can, I'll design the bracket and send him the specs.

Is anyone else interested in this?

The catch can I'm going to be ordering is less than $150 and made by a good shop from stainless steel with either a brushed finish or wrinkle black finish.
The mounting brackets will be custom made, and I can have him do either a brushed finish or black finish.

*NOTE* that the finishes might not match each other since they're coming from two different sources. I'm going to get a brushed stainless bracket with wrinkle black catch can. That way, the catch can should match my intake manifold and the bracket should look OEM.

If anyone else is interested in this, please let me know asap and I'll see if I can get a group deal.

 

As someone whose track car can literally send an oil cloud out the back, I value catch cans.

I'm new to the vantage, but if this is as much of an issue as it seems, count me in. Let me know what you need from me

And thanks for doing the work!

 

So long as there aren't any real differences in mounting points over the years, this should be universal for all V8 Vantages.

I'll get the cost of the parts (catch cans, mounting brackets, hoses, clamps), then order all the parts and put the kits together, test fitting on my car to ensure they work, then shipping out the kits to whomever buys one. I have a PayPal that people can use to pay me for the kit.

I'm not going to be making any money off of this, it's my contribution to a forum full of info I'll be charging only for the cost of parts and shipping.

Anyone local to me: I will happily install the kit and accept payment in craft beer in lieu of money for labor.

Everyone else: I'll do a write-up on installation. Should be pretty straight-forward. That part of the engine bay is extremely easy to navigate.

 

 

 

yeah, i really like the design, build quality, and overall look. very clean and simple, and a great piece that will blend in nicely.

i was thinking about the easy drain valve when i first started looking at this catch can, and i think i'll leave that open to whomever wants me to build a kit for them. personally, i'll pass. two easy bolts and the can is removed in under a minute and can be drained as needed. (it'll be up top and nothing will obstruct removal.)

with the drain valve and dump tube, you have to position a drain pan (or whatever) in the right place, reach down to the bottom of the catch can to open the valve, and you risk residual oil dribbling out of the tube after the valve has been closed. just my two cents, of course, but anyone that wants a kit can easily order the valve and put it on (i'll supply the link to order it). i'm personally not going to bother with getting so specific with various options - each person can order it themselves.

honestly, the hardest part about this so far is finding pre-shaped SAE30R7-rated hose. heater hose is easily found, but that won't withstand the oil/fuel that this hose will get exposed to.

 

Can't ... give ... more ... rep points ... Arrrgh!

 

I braved the 187F heat and 100+% humidity (isn't that, uh, technically just water?) to get a peak inside my intake manifold. After seeing the buildup behind the butterfly plate in my throttle body, I wanted to see how everything else back there looked. Pulling the throttle body is very easy:

1) Disconnect the main intake hose from the throttle body. Release the sawtooth clamp holding the main intake hose onto the front of the throttle body. These are easy when you figure out their trick. (I use a couple screwdrivers - one to open the outer teeth and the other to work the inner teeth out.) Once the sawtooth clamp is released, you can leave it limp or pull it off entirely, it's easy to deal with. You can easy slide the intake hose toward the front of the car. If you want to, remove it entirely (two more sawtooth clamps, one on each side further to the front of the car). Or just move it around as you work around it, which I did and was easy enough.

2) Remove the throttle body. There are four bolt holding the throttle body to the intake manifold. Remove them. Don't lose the metal gasket between the throttle body and intake manifold. Once the four bolts are removed, disconnect the drive-by-wire harness and that's it. If you're just cleaning the throttle body, you can leave the harness connected (which is what I did).

3) Clean the throttle body. Use carburetor/intake cleaner and a lint-free paper towel (I like the blue shop paper towels you can get at any parts store).

4) Reassemble in reverse order. Don't forget the metal gasket!

Before cleaning, lots of black buildup:



After cleaning, lots of shiny:



The inside of the intake manifold looked pretty clean, except for inside this hole inside the intake manifold, which is between the throttle body and the intake runners that lead to the cylinders.



I put my finger in it, and it was gross:



It looks like this hole leads to the EGR, which supplies filtered air to the exhaust (helps improve emissions readings). I pulled the EGR from the intake manifold and there was some buildup, though not the standing oil like in the plastic tube between the PCV and intake manifold - which is what I was expecting.

My thought process here, and this might be a stretch, is that excess oil is coming through the AOS and PCV. This oil is mixing with intake air and contaminating the air-fuel mixture. This causes the car to pull timing, resulting in reduced performance, worse fuel economy, and other engine-related buzzwords connotating less-than-ideal conditions. The oil getting into the intake air also contributes to the sludge buildup in certain parts of the intake manifold, like the duct going into the EGR (the dirty hole pic above). The buildup in the duct to the EGR is sending bad air to the exhaust, which is not helping, possibly even hurting, emissions. I've got a persistent CEL for my emissions system, and I wonder if this is related.

A catch can might help solve a lot of these problems by grabbing the oil that's causing the issues. Or it might not.

 

I shot an email to the manufacturer and got the dimensions of the catch can on Saturday evening and got a prompt email this morning. Now that I've got the dimensions, I can make a rough mockup to make sure everything fits how I want it to.

I think I've found some hoses that will work. I want the hoses to look OEM so really those are the hardest part of this!

 

Sign me up for a kit, with a pet****/hose if you can get them, or without, either way I will try it. I am under the car changing the oil with a pan anyway once a year so it is easy to do the pet****/hose alignment. Further it would look like I really know what I am doing, very professional.

This morning I talked to my mechanic, Kyle at AM of Troy. He agrees, it is an oily nightmare inside our V8 manifolds.

My compliments...your method of presentation is exceptional. Detailed, well illustrated and funny. You have the ability to reduce the complex into a set of easily followed steps.

 

Progress report time...

I've spent way too long looking for pre-molded SAE 30R7 hose, only to find out that this is an option:


Looks like my kit will be for the setup above, which will allow me to use 90-degree fittings to easily route the hose. This helps more than y'uns can possibly know because I've been beating my head against my desk trying to find proper hosing for this to look OEM.

I'm thinking for my kit, I'll be using the original AOS->PCV hose, which will be cut in half and flipped around (meaning, the side that was connected to the PCV will now connect to the AOS). This will make fitment work wonderfully since the hose must be routed between the AOS and engine block, which has limited space and requires a molded hose for awesomeness. And, it's also available through through your dealer if it needs to be replaced. (Remember: measure twice, cut once!)

My napkin-scale drawings say this should fit quite nicely. If I can't find a molded hose for the PCV side, then worst case scenario the PCV side will have non-molded hose. The only real difference here is the non-molded hose have a curve to it rather than an angled form-fitted look like the others in the area. Regardless, it will still be fully functional. Plus, the non-molded hose will be largely out of view.

So... everyone good with this so far?