[Area 473]

Rodney, in a perfect world...lol, yes they would.

Mjw, at least that would be something!

Mobius, that would work too.

The point is and I understand the reason for it, but fail to see the lack of a drain. Eventually it will fill up and dump it into the air box....not a good idea. I made a catch can for my Super Cub plane where the cc vented directly to the great outdoors in order to keep the oil mist off the belly. It had to be insulated and checked so it wouldn't freeze up in the winter and over pressurize the engine. Maybe this is rocket science which I don't think I took a class in.

Kurt

 

[mjw930]

Kurt,

The chamber was never designed to catch liquid oil, aka, the burp. It was designed for vapor retention (thank you EPA). Since oil in suspension will eventually precipitate if the airflow is slowed down (the basic principle of a catch can) oil will line the walls of the chamber and eventually collect in a pool at the bottom. I believe the additional reason for the separate chamber is to prevent that from happening on the actual intake runners and they believe and proved through high mileage testing that the buildup did not warrant making that area cleanable. Probably a mistake on their part but also highly unlikely enough oil would ever build up over the lifetime of the car to be a problem. Of course this assumes your dry sump doesn't burp liquid into it.


Sent from my iPad using Corvette Stingray Forum

 

[vabuckeye]

I checked my air filter last night prior to adding the elite can and found there was no oil there. The oil level was in the middle of the acceptable range. My Z51 now has 12,000 miles on it. At 6,500 miles, there was oil in the air filter, but the next 5,500 miles, there is none. The service tech told me it was my aggressive driving and overfilling the oil, but I'm not buying that as I didn't cut back on my style of driving, if anything it has gotten more aggressive. Either way, I now have a catch can system on it as a backup.

 

[Tuner Boost]

That is essentially what I understood from the explanations about the importance of the "air bridge suction", however, if the pressure in the crankcase builds, it will still push to the Intake Manifold. Pressure will "push" in the absence of vacuum to "pull".

It is also hard to understand how there will be vacuum immediately ahead of the throttle body, especially as early as 2/3 throttle as stated in a couple of late posts.

The reversion pulses dont reach past the snout where the TB bolts on, so suction/vacuum is present just upstream of the TB where there is none at the intake manifold vacuum barb at that throttle level (anyone with a boost/vac gauge can verify this). So at all times of higher RPM and open throttle there is suction to use to continue evacuation at this placement.

I took the air box of last week and checked it for oil. the box itself was clean and dry along with the filter and the intake. I turned the air box upside down and had a couple drops of oil come out of the well where the clean side hose connects. I reached in and stuffed a paper towel in twisting it around till I could no longer get anymore towel in. Pulled it out and there was some oil on the towel, not much. The well where the pcv hose attaches was clean. The car is at 6,000 miles and one oil change. The oil level is running center of the has marks since the change and that's at my 7 min. baseline. Prior to the oil change it was toward the upper end and I'm assuming at the oil change the new 9.5 fill was done.

Prior to taking the whole box out, I just pulled it loose at the engine side and looked down in the air box and into the intake, it was dry at that time. I wouldn't have noticed the oil in the well where the hose connects so I don't know if this was from earlier or a more recent event.

Some random thoughts:

I think from what has been said here that if the oil level was too high from the factory/dealer top off, a burp during break-in could cause the worst case scenario, oil in the box, filter and intake. If the oil level was at the top, ie. old specs, then you could experience oil in the trap and perhaps the box and intake during break-in. If the oil level was on the lower side and or if there was less burping during break-in, you probably won't see any problems at all.

I have to wonder why they didn't put a drain plug or removable catch can in the bottom of the clean side well on the air box. It certainly would be good way to monitor and remove that oil from the well. I suppose one could drill a hole and thread a stem with a catch can attached?

Kurt

You could, but once it has made its way to accumulate in the sump depressions, plenty is already been flowing into the intake air-charge itself. GM has molded in sumps like this for years. The V6 DI engines have a deep sump just inside the IM snout and the snout angles down to collect oil. The explanation of capturing vapors for the EPA is stretched a bit....it is to collect oil (un-officially) as you see them do. And the last C7 in for a free install had almost nothing in the airbox/filter, but the IM itself was saturated and puddled with it.

Kurt,

The chamber was never designed to catch liquid oil, aka, the burp. It was designed for vapor retention (thank you EPA). Since oil in suspension will eventually precipitate if the airflow is slowed down (the basic principle of a catch can) oil will line the walls of the chamber and eventually collect in a pool at the bottom. I believe the additional reason for the separate chamber is to prevent that from happening on the actual intake runners and they believe and proved through high mileage testing that the buildup did not warrant making that area cleanable. Probably a mistake on their part but also highly unlikely enough oil would ever build up over the lifetime of the car to be a problem. Of course this assumes your dry sump doesn't burp liquid into it.


Sent from my iPad using Corvette Stingray Forum

If it did not burp, then your correct. Vapors would always be present at times and condense and oil collects at the lowest point, so your correct. This was not designed to deal with the burping.

Watch what GM does over time, but as this has been the same since 2006 with the C6 Z06 dry-sump, I don't foresee anything real robust coming from the factory any time soon.

 

[BatMobile]

Letting everyone know that I've had the clean side sep on from elite since the car had 60 miles on it. Also have had the dual valve catch can on the same amount of time from them too. Noticed at 4000 miles that oil was comin out of drilled hole into coupler. Had dealer dismantle and everything was covered in oil. Filter, box, coupler.

They cleaned everything out and replaced filter, but this goes to show that if car came from factory overfilled (mine did, had oil change and at correct level at 3800 miles) that even with a clean side sep oil will burp out of your z51. I'm sure it would have been worse without the sep, but my experience should be proof and reason to get your oil level correct, and add the clean side sep.

 

[mjw930]

I would argue it's only evidence you need to have the proper oil level. If oil got past the clean side separator due to an overfill you just proved its worthless.

 

[rdslon01]

I would argue it's only evidence you need to have the proper oil level. If oil got past the clean side separator due to an overfill you just proved its worthless.

That is not true. There is a range where the clean side separator works to contain burps unless the overfill is tremendous. What he has shown is that it cannot hold back Niagara Falls, for example.

 

[Tuner Boost]

That is not true. There is a range where the clean side separator works to contain burps unless the overfill is tremendous. What he has shown is that it cannot hold back Niagara Falls, for example.

You are correct. There is no way to stop an overfilled tank from forcing right through the cleanside unit.....take a quart of oil and pour it in and fill it up, it will come out the other end. When the oil level is correct, it traps those vapors that momentarily push backwards keeping the oil from entering the intake air charge.

Just had a C7 in here Friday that we dumped a ton of oil out of...and his dipstick is on the bottom of the hash marks:

And one from earlier in the week who sent this email. Ben from Weapon X hooked him up and this was copied to both of us:

Ben-

It is running great. Just like it is supposed to. No oil blowing out of the blow off valve like a whale spewing water out of his hole. Car is a blast. I will call you in a bit, Ben to get the wheels and tires ordered. And ask about a couple of other items.



Craig Douglas
ASG Automotive
President
ASG Automotive - Indianapolis Auto Repair


On Fri, Sep 5, 2014 at 1:13 PM, Ben Herndon <ben@weaponxmotorsports.com> wrote:
How's it running today Craig?


On Thu, Sep 4, 2014 at 3:38 PM, Craig Douglas <asgindy@gmail.com> wrote:

Good afternoon gentleman-

Today I was able to finally successfully drive my C7 without oil blowing all over the side of my car!

Tracy- thank you for getting me more than I needed to do the final install. The only missing item was the 3/8 T to 5/32 for the blow off valve but I was able to improvise. I am happy to return all of the hoses and fittings that I didn't use if you would like to have them back.

The first time I went full throttle after the install I got some shooting ducks around 5K RPM'S. It happened 2 or 3 more times but eventually cleared up. I wonder if that was all the oil belching out of the system? I suppose I will know more when I drive it home tonight.

I have attached some final install pictures. The only item that I would like to do better is the filter on the dry sump tank. It kind of sticks out.

Please share your thoughts.

Thanks again guys for all of your help.

Craig Douglas
President
ASG Automotive

 

[Tuner Boost]

I can also confirm GM has molded this "catch basins" into the air boxes, and with the v6 DI engines, just inside the IM snout (which is angled down to assist oil collecting in them via gravity) as they have known very well about the oil issues with DI engines. In fact, the intake manifold on the GM 3.6: V6 even have a boss cast into them where a pet cock was tested early on allowing the techs to open and drain, but far to many got confused and accidently left them open instead of closed causing vacuum leaks that they abandoned it early on, but they are still there for 2015:

And these are wet sump engines, so the issue comes from the PCV system itself....no over filled oil sump:

You never want any oil entering, because if enough comes through to accumulate in the amounts your seeing, a ton more is ingested via the intake air charge directly into the combustion chamber as most remains suspended as a mist. So if your seeing ANY accumulation in the air box or the intake manifold, (and even the wet sump C7's we remove the IM we can dump oil out of all of them, wet or dry sump.

So a band-aid that you just wait until condensed oil is filling the molded in depressions, you have already ingested a ton into the combustion chambers. Any one that doubts any of this just take the few minutes to remove your intake manifold (tales 15-20 minutes with minimal tools) and tip it on its snout and watch the oil drain out. Then your right up close to your intake valves...shine a flash light in and see the level of coking and there will be no more debate (except the few truly ignorant that will believe the deposits as fine).

But there is no need to keep arguing on the subject, those that are happy as is and don't believe this is harming their engine, performance, longevity, no one is forcing them to address it. They should be content to continue as it comes from the factory. This information members are sharing is only for those that do want to make sure they are caring for their baby the best they possibly can and do want to learn more.

Cheers!!

 

[AndrewY]

When is GM going to start installing a clean side separator standard from the factory on Z51?

A catch can was installed on my 2014 Z51 Stingray by GM at no cost to solve the oil in the intake manifold problem. The Chevy dealership that did the istallation was recently sold to a Buick GMC dealership. I took my car to the new dealership for an oil change and to see how well the catch can was working. I was hoping that the technician that installed the catch can at the Chevy dealedship had gone over to the new one. Unfotunately that was not the case. The technician at the new dealership was unfamiliar with the oil in the manifold issue and catch cans. He called GM to educate himself about this paticular issue and in the process was told that the 2015 Stingrays come standard with catch cans. I did a google search to verify this but found nothing. If this is true it is an interesting development. By the way, my catch can seems to be working.

 

[mjw930]

To be clear, GM didn't install a catch can, your dealer did and not at the direction of GM. No, there are no catch cans installed on ANY GM product in 2015.

 

[sharkray]

I'm not a tech guy but how is this hurting the engine?

 

[CK_Bladesmith]

I'm not a tech guy but how is this hurting the engine?

Blowby gets on the back of he valves and burns to them creating a hard coking effect. Over time it will rob power and airflow from the engine basically. Also if any of that hard buildup gets into the engine it could be really bad news. In a port injection engine you don't have to worry about it as much, if at all because fuel sprays on the back of the valves and cleans them off/keeps them cool. Not the case with a direct injection engine as all of the fuel is sprayed directly into the cylinder instead of on the back of the valves, in a nut shell.

 

[sharkray]

Thanks CK