Oh, for those with mini's, here are tons of before and after pics from owners that actually did remove their intake manifolds:
http://www.minitorque.com/forum/f15/...es-here-32763/

 

did i misunderstand something I thought I heard in the video showing how to clean C7 LT1 valve stems damaged by coke buildup, at low mileage, from GDI on those engines?

I THOUGHT I heard it said that by under-filling dry sump tanks by one quart of oil, that a major amount of oil could be prevented from "burping ??" into the intake stream?

and, if this is true, would it make a similar reduction in coke being deposited(and maintained) on the valve stems?

this would seem as a much-too-simple solution to the problem.

OR...is it REALLY true that valve stem deposits are still a major problem simply because GDI does nothing to spray the valve stems clean?

and this would be regardless of dry sump tank oil levels?

so, are there really two problems here for LT1 GDI engines:

1) that the oil level in Z51 dry sump tanks causes burping of oil into the intake stream thus causing its own problems.

2) that GDI engines' valve stems are bound to grow evil deposits simply due to the lack of valve stem spray cleaning by GDI

thanks, in advance, for an answer to these questions.

 

yup two different problems. and a catch can WILL NOT stop the dry sump problem. This is why i started to use intake valve cleaner.

 

I see that GM has included a catch can on the LT1 engines mounted in 2016 Camero's--they must think their is a problem. I wonder if they will do the same with LT1 engines in other models? Common sense seems to dictate they will.

 

I have 2 sets of heads and the level of deposits are the same. One on my car an another set I bought to be ported in the future. It's a Z51 now with 13,000 miles with a RX catch can installed ar 11,000 miles.

I've use the CRC Intake valve cleaner twice but haven't determined how effective its been yet. I posted pictures earlier when I ported the intake manifold and there was a start of coking. Not serious in my opinion.

The oil was overfilled when I picked it up at the museum in October 2013 and I found oil in the intake tube from burping. I now keep the oil level a fraction below the middle on the dip stick. After a very spirited run around the Twisted Sisters in Texas, I only got about a table spoon of oil from the catch can.

 

The oil catch can on the 2016 Camero with a LT1 even has a built in drain tube connected to the wet sump pan to eliminated the need to dump or drain oil that is captured in the can.

 

So, what's the difference between the two:
Naturally Aspirated (Non-Boosted) - Single Check Valve Catch Can
Naturally Asperated High Output (Heavily Modified) - Stage II Catch Can

I'm not going FI on this car nor am I going to modify the hell out of it with a cam. I might go LTs and !CATs after the warranty where I can tune for the power.

... and do I need a clean side separator?


Elmer

 

I had the same question as I have a dry sump Z51 w/ your mentioned possible mods above (headers, X pipe and tune), I had already ordered the stage II kit and was just second guessing it and this was the response from the builder of it.

'Currently the drysump tank is part of the flow path of the clean, or fresh air that enters the crankcase drawing fresh filtered and MAF metered air in from the main intake air bridge. It is quite common for the crankcase vapors to cause a "burp" from the oil tank and push oil out the OEM line into the intake airbridge upstream of the throttle body and ingest through this path. The clean-side separator replaces that OEM line and then has the vertical path for any oil to travel and if any oil does enter, the coalescing media inside the CSS chamber will stop and trap this oil allowing it to flow back into the tank when flow returns to the correct path of in only.

The CSS is similar to GM's solution, the plastic empty 1LE clean side separator but it's 1/2 the price and a good deal more effective as well as quality, 6061 billet construction.'

So you take your oil filler cap off (on the dry sump system) and replace it w/ their 'push in' cap which has the media imbedded in it that they mention and the line then runs to the cap vs the inlet next to it on the factory location. I can report that after the first 300 miles of driving I had a good half inch of oil in the can! I make sure I run only about 9 quarts of oil and that is registers on the lower side of full on the dipstick when hot and I still get oil collecting in the can. Glad I spent the few extra bucks and went w/ the stage II. There is also some additional explanation on their web site as to how it all works under vacuum etc. I am certainly not an expert on it all but know its working. Hope this helps a bit.

 

The only potential problem I see is it is not just oil that appears to get caught into the can. On my 2008 it was a watery goo. I'm not sure it is a great idea to dump that gunk back into the pan.

 

On the dry sump engines, there are two possible paths to get oil into the intake, and therefore on the backs of the valves. One of those paths is oil from the dry sump tank, which MAY be related to overfill. Many owners prefer to run about 1/2 quart low to prevent this.*

The other path, though, is combustion vapors coming through the PCV system. This has nothing to do with burping from the dry-sump tank, and reducing oil volume won't do anything about it. It affects both wet and dry sump engines. How big a problem this is is subject to much discussion and disagreement. Some don't think it's an issue at all. Some think running a catch can will help, if not totally resolve the issue, or is cheap insurance. And some think it's an issue, but don't think a catch can is a good enough solution and think only methanol injection is the solution.

Some other engines (VW is one) have had severe problems with deposits requiring walnut shell blasting to clean the valves. GM has said valve stem deposits on the LT1 are a "cosmetic" problem only, but has now installed a factory catch can on the new Camaro. Reach your own conclusions. The answer to your last question is "yes." The lack of fuel and detergents on the backs of the valves on many DI engines is the root of the issue.


* The idea that overfill of, or even completely filling, the dry sump tank leads to oil in the intake is widely accepted by most here, but there is an alternate school of thought that this is caused by foaming of the oil caused by the sealants used in the dry sump system, and as long as you do the 500 mile oil change it won't be a problem.

 

OK.

thanks to all who have responded to my post and clarified the two distinctly different issues.

1) that the lack of cleansing fuel "spray" onto the valve stem causes obvious problems in GDI engines.

2) that filling the dry sump tank(either overfill or just filling it to the full mark on the dipstick) can/does cause the burping issue with the result that oil enters the intake system.

Got it(I think).

However, let us all step back and consider the rationale for, and the operation of, dry sump systems.

Most of you already know the following:

Dry sump systems are widely used on race cars so that:

1) when a car corners at high g rates, not attainable by most road cars, the oil will not slide away from the oil pickup inlet causing low/no oil pressure.

2) dry sump oil pans, not tanks, can be made much shallower than a typical wet sump oil pan thus allowing the engine to be placed lower in the car with the CG for the entire car also being lowered. this causes greater cornering capability.

So, when the Corvette and Camaro designers did their work, they specified dry sump systems for the models, especially the Z51, that were most likely to corner at high G rates.

Great stuff, right ????

Well, the dry sump also provides one additional benefit.

That is, that the dry sump contains much more oil than will be needed by the "average" Z51 driver for the g rates he/she attains in car unless they track or autocross(???) the car.

This means that many of us with Z51s(that are dry sumped) can very safely UNDERfill the oil slightly(at least one quart) with no likely harm to the engine. Unless one is tracking or otherwise generating high g forces, an absolutely full dry sump tank is not necessary.

It's just that Tadge and team saw the Z51 and Z06 as likely candidates for tracking and high g generation. Hence they provided a dry sump system even for those many of us who will never generate high g forces. It's a blessing in disguise for those of us who now have way more oil on board than we need.

So, I would feel completely safe under filling the dry sump tank if it prevents oil in the intake system.

 

I also read a BIG contributor to oil/carbon build up on the intakes valves is the AFM system. When AFM shuts off 4 cyclinders compression pressure is reduced on the piston rings allowing signficant oil blowby.

This is why I run an AFM disabler on my C7 it stops the AFM system from activating 4 cyclinder mode.

 

So we should see more build up on auto trans cars. Seeing how my manual never sees AFM being in sport mode. Which is where is sits 100% of time.

 

 

I'm of the foaming oil due to the breakdown of the sealants club. I had the burp, flushed out the oil on the refill and have never had an issue no matter where I set the oil level as long as it is on the hatch marks on the dip stick.

Elmer

 

Whereas you have shown a lot of great information here and raised awareness, when you are trying to sell your products it could appear that you only have one motive for creating this post and may cause
some of the members to question your credibility .

Just my .2 cents

 

Yes we have a product that works. And rather just push a product with prices, we're being an integral part of CF by explaining and answer questions about the product that we feel benefits the CF community. Is this a good explanation for you? Can we go back to what we are doing and at the same time making a little money to pay for bills now? Thanks.

 

Hey guys and gals. We are running the January special on the catch cans. Here is the link:

http://www.coloradospeed.com/?main_p...ha_filter_id=0

NOW is the time to get one if you need one. Not everyone will need a catch can but by the disucssion, it is a good thing to have. We'll never do this price again on these so January is the month. Thanks!

 

Thanks for having "NP" in cancelling my order. BTW, your website is down.


I get the attached screen when I go to your site.

Either you're down or I'm banned!



Elmer

 

Website is still down.