[larietrope]

I'm sure this has been addressed but would someone give me a quick take on it. I'm buying a 40K plus performance car from GM.
Surely they are aware of the blow by subject. Why is it they don't address the issue from the factory ?
Then I understand if you install an oil separator it can effect warranty.
Should I do nothing and let warranty cover any problem or take a chance and install an oil separator ?
How does the blow by affect performance of the engine and how long (miles) can it go before being affected ? Does this issue affect Ford and Chrysler ?
Thanks.

[whiteboyblues2001]

This can be a long, complicated, and controversial subject, but let me try to give you the cliff notes.

The 6th gen Camaro engines are all direct injected, and oil vapor can accumulate in the intake system including the backs of the valves. Over time, this can build up, and fuel usually has some detergents in it to help clean this up. BUT, since our cars are direct injected, no fuel goes by the back of the valves. This has caused some issues in some cars, but the Camaro has not had that issue in the past with the V6. The new LT1 has an oil spearator system built in to address this, and it is different, and supposedly better than the one in the Corvette version of the LT1. But it only cleans one of the two sides of the source of oil vapor.

I also believe that most if not all of the cars that have the more severe issues with this are the smaller displacement and/or turbo engines. Having fewer and smaller cylinders means there are less and smaller rings to hold back the blow-by. Which means more blow-by, and therefore more accumulation.

So far, there really hasn't been any issues with this in the Camaro's version of the LT1, but perhaps enough time hasn't gone by yet to make a determination.

There are a couple of things you can do for this. One, is to install a catch can to help eliminate most of the blow-by, but in some extreme instances (not very many, but it has happened), GM can deny a warranty claim because of the catch can. But, if you have an issue, you can always take your catch can off before you take it to the dealer.

Second, you can use a product like Seafoam. Seafoam comes in many forms, but I am talking specifically about the spray version that you spray in your throttle (the can comes with a small hose that you put between the intake boot) to spray into the intake when the car is running. This can clean much of the crud off the intake valves.

Third is to do nothing, and trust that what GM developed for the Camaro is enough.

Another factor to consider is how hard/agressive you will be driving your car through it's life. If you are just a daily driver 90% of the time, with some spirited driving, you may not need anything, because there won't be as much blow-by. But, if this is a weekend track toy that is going full throttle most of the time, you might want to think about additional protections.

[Drags1998]

Well Said^^^^^^^

[Mr. Wyndham]

There is also a fourth option...and that is after 100,000 miles or so...when the buildup starts to actually have an measurable effect on the car...you take it in for a crushed walnut blasting service done.

Brings the valves/heads back to brand new condition.

[cellsafemode]

seafoam like a boss before every oil change. Maybe 10 bucks every 6 months to a year.

Should keep you pretty clean. I'd suggest doing it even if you have 300 dollar catch cans with vacuum assist modifications.

[gdgraph]

Post #2 is very good, I agree. I'll just add on my opinion for consideration.

I believe that GM doesn't install a catch can (like the aftermarket ones) because it would shorten the maintenance interval requirements and not everyone that owns a car would remember to empty it on time causing them more issues than it is worth. A direct injection engine can survive until the end of the warranty without a catch can so why bother.

My opinion is that if you plan to keep the car stock, you are covered by your power train warranty, so an aftermarket catch can maybe isn't worth an investment since you are covered, I'd just do periodic seafoam cleaning.

If you plan to mod or race frequently getting an aftermarket catch can might be worth something to look into. If anything happened to your car I'd remove the catch can because of that one horror story about a guy with an engine failure that was denied coverage because of a catch can.

Seafoam is a great way to keep everything clean on a direct injected engine because it will clean your intake runner and intake valve. There's also a treatment you can get to clean out the injectors also.

[Ryephile]

Originally Posted by larietrope

...Why is it they don't address the issue from the factory ?...

They did as much as their budget and design constraints allowed them to. There's a factory PCV AOS. It sits just above the water pump. You can see the lines from the valve covers entering a little black plastic box, and the one leaving going to the throttle body tube.

There's additional separation to be had with the other crankcase vent coming from the block valley to the throttle body; that's where aftermarket catch cans help catch additional vapors.

Point is, GM engineered it good enough for the warranty period and affordable, but there's room for improvement if you want to spend the time and money ensuring you engineer or buy an acceptable solution. Of course any warranty concerns are your prerogative.

[jreagle56]

and in a perfect world, the auto manufacturer would have engineered and developed a factory PCV oil separator large enough to hold the blow by and condensation that is collected during an OCI, added the procedure for emptying when the oil change is done by a tech at the dealer or local garage or user at home. then an after market system wouldn't need to be considered and weighed against voiding a warranty vs not.

a simple ball valve or drain plug on the bottom of the new patented separator emptied into the waste oil drain pan at the time of an oil change service. it would take an additional 5 minutes or less to drain.

I am really surprised that this is not part of the Direct Injection Engine R&D and manufacturing engineering process. Its like they quit before completing the design development; instead opting to use the 50 year old design concept of handling PCV blow by.

Sorry for venting... using an Elite E2 on my LT1. The larger reservoir extends the emptying intervals.

[jwober]

[QUOTE=Another factor to consider is how hard/agressive you will be driving your car through it's life. If you are just a daily driver 90% of the time, with some spirited driving, you may not need anything, because there won't be as much blow-by. But, if this is a weekend track toy that is going full throttle most of the time, you might want to think about additional protections.[/QUOTE]

+1

One addition thought. After doing some research it seems that one of the main reason for valve carbon is due to the oil breaking down. GM had a recall to recalibrate oil life on some of the 4 cylinder engines with direct injection, reduce the carbon build up by more frequent oil changes. That being said I think that is one of the reasons the oil capacity was increased to 10 quarts on the LT1. IMHO

[cellsafemode]

Blow by isn't part of the correct way it's supposed to work. That's probably why there's not a huge effort by the OEM to implement a catch-can system. The goal is no blow-by.

I have two catch cans on my v6. I've had them on now for thousands of miles and have yet to have anything to show in them except a barely dirty blue cloth from wiping the insides of them when i cleaned them once.

So everything appears to be working on mine as intended. I would consider those seeing significant blow-by as dealing with either some defect or design flaw or operating well outside of the designed power of the engine that produces that blow-by. The catch-can is just a band-aid to not have to re-engineer the engine to correct the problem.

[jwober]

There are a number of posts where people, that don't race their cars on a regular basis, have installed catch cans and have never found anything in them.

[glenB]

Originally Posted by jwober

There are a number of posts where people, that don't race their cars on a regular basis, have installed catch cans and have never found anything in them.

And there are many people who don't race on a regular basis and have found oil in the can.

Direct Injection is a mixed bag, using GMs Top End Cleaner at about 20-25k miles will help. GM put a lot of time and have a patent on the VC design so only time will tell. The DI 4 banger, GMs first didn't fair so well and gunk ed up the valves pretty good. Installing cleaners in the gas won't do diddly. Mega power also makes kits.

[Black_FiFTY]

If you don't plan on owning the car for more than 4-5 years than I wouldn't bother. Install it for longevity. It's an easy install so do it yourself and just remove it before taking it in for warranty purposes.

[wavsine]

Originally Posted by larietrope

Why is it they don't address the issue from the factory ?

They do. Not with a catch can but with the valve timing schema. The theory is to keep the valves hot so they will burn off light carbon deposits.

Originally Posted by whiteboyblues2001

This can be a long, complicated, and controversial subject, but let me try to give you the cliff notes.

The 6th gen Camaro engines are all direct injected, and oil vapor can accumulate in the intake system including the backs of the valves. Over time, this can build up, and fuel usually has some detergents in it to help clean this up. BUT, since our cars are direct injected, no fuel goes by the back of the valves. This has caused some issues in some cars, but the Camaro has not had that issue in the past with the V6. The new LT1 has an oil spearator system built in to address this, and it is different, and supposedly better than the one in the Corvette version of the LT1. But it only cleans one of the two sides of the source of oil vapor.

I also believe that most if not all of the cars that have the more severe issues with this are the smaller displacement and/or turbo engines. Having fewer and smaller cylinders means there are less and smaller rings to hold back the blow-by. Which means more blow-by, and therefore more accumulation.

So far, there really hasn't been any issues with this in the Camaro's version of the LT1, but perhaps enough time hasn't gone by yet to make a determination.

There are a couple of things you can do for this. One, is to install a catch can to help eliminate most of the blow-by, but in some extreme instances (not very many, but it has happened), GM can deny a warranty claim because of the catch can. But, if you have an issue, you can always take your catch can off before you take it to the dealer.

Second, you can use a product like Seafoam. Seafoam comes in many forms, but I am talking specifically about the spray version that you spray in your throttle (the can comes with a small hose that you put between the intake boot) to spray into the intake when the car is running. This can clean much of the crud off the intake valves.

Third is to do nothing, and trust that what GM developed for the Camaro is enough.

Another factor to consider is how hard/agressive you will be driving your car through it's life. If you are just a daily driver 90% of the time, with some spirited driving, you may not need anything, because there won't be as much blow-by. But, if this is a weekend track toy that is going full throttle most of the time, you might want to think about additional protections.

The irony is that it works just the opposite. Hard driving at full throttle would actually be beneficial for burning off light carbon deposits from the back side of intake valves. Running the engine at over 4,000 rpm for an extended period on the highway has been called an "Italian tuneup" This causes the valves to get cherry red which combined with the high intake velocity helps burn off light carbon deposits. Extensive idling is bad for a DI engine.

Originally Posted by Mr. Wyndham

There is also a fourth option...and that is after 100,000 miles or so...when the buildup starts to actually have an measurable effect on the car...you take it in for a crushed walnut blasting service done.

BMW discovered that walnut shell blasting is the only thing that works to remove tough carbon deposits. Ford has not yet approved this method on their ecoboost engines and specify head replacement under warranty if the carbon is severe enough.

Originally Posted by jwober

+1

One addition thought. After doing some research it seems that one of the main reason for valve carbon is due to the oil breaking down.

One thing that has not been mentioned here is NOACK, the oil volatility rating of the oil. It is important to use the lowet NOACK synthetic oil you can find in a DI engine. Unfortunately, NOACK numbers are not always disclosed and the brands that still publish their number have been creeping up recently. Pennzoil Ultra used to be the best but it has been discontinued.

Originally Posted by cellsafemode

I have two catch cans on my v6. I've had them on now for thousands of miles and have yet to have anything to show in them except a barely dirty blue cloth from wiping the insides of them when i cleaned them once.

It is oil vapor that is the enemy of valves and many cheaper catch cans do not trap vapor unless they have a filter.

Originally Posted by glenB

Direct Injection is a mixed bag, using GMs Top End Cleaner at about 20-25k miles will help. GM put a lot of time and have a patent on the VC design so only time will tell. The DI 4 banger, GMs first didn't fair so well and gunk ed up the valves pretty good. Installing cleaners in the gas won't do diddly. Mega power also makes kits.

Ford did a good job on their normally aspirated DI engines using their valve timing schema but have had trouble with their turbocharged ecoboost engines developing carbon on the valves.