Intake manifold off with pics of intake valves with deposits.

tnchevy · January 21, 2016

I would love to see what the valves look like on a truck with 30k miles that has had a catch can on it the whole time. Maybe better but could also be about the same as one that didn't have a catch can.

Willshire · January 21, 2016

If a catch can picks up so much water in the winter, does the water that gets sent back into the engine (with no catch can) lessen the effect of oil coking on the valves? There is after all wayy more water going in than oil right?

GDI Tech · January 21, 2016

I would love to see what the valves look like on a truck with 30k miles that has had a catch can on it the whole time. Maybe better but could also be about the same as one that didn't have a catch can.

We have gone as far as 63,00 miles and the vales are not spotless, but look like the valves at say 5k miles w/out a system installed.

If a catch can picks up so much water in the winter, does the water that gets sent back into the engine (with no catch can) lessen the effect of oil coking on the valves? There is after all wayy more water going in than oil right?

I think it does have a small effect in theory, but we have not found a way to stop just the oil and other compounds and not the water. Yes, water and other contaminants are going into the oil if not evacuated. And the stock PCV system only uses the intake manifold vacuum, so when accelerating the stock system does not evacuate/remove these. Only at idle, cruise, and deceleration (which is most of the time). So the stock PCV does pretty good on a naturally aspirated engine in evacuating, but all is then ingested and passes the valves. If it was water alone, I am pretty confident it would help reduce the coking. Good thinking!

Haus_Z71 · January 22, 2016

Is there any info on how installing a catch can might affect warranty? Having a custom tune, I expect this should be the last of my worries, but I'm curious what a dealer is going to say when they see an aftermarket catch can.

What pisses me off about all this is if I have an engine issue because of this build up, and I take my truck in for warranty work, they are going to ignore the fact that this engine is designed to dump water and oil back into the intake and blame it on my custom tune.

jrob56 · January 22, 2016

Is there any info on how installing a catch can might affect warranty? Having a custom tune, I expect this should be the last of my worries, but I'm curious what a dealer is going to say when they see an aftermarket catch can.

What pisses me off about all this is if I have an engine issue because of this build up, and I take my truck in for warranty work, they are going to ignore the fact that this engine is designed to dump water and oil back into the intake and blame it on my custom tune.

Yeah with that tune I wouldnt worry about the can. I put one in and had oil changed at dealer once and they never said anything about it. Havent heard anyone on this board with an issue yet. Its the only mod Ill be making that COULD affect my powertrain warranty but I highly highly doubt it.

GDI Tech · January 23, 2016

Many "catchcans" do void the warranty if they defeat the PCV systems functions and cause damage (as I have gone over earlier in this thread) so that is a legitimate concern. Any that use a breather, mix clean and dirty sides together, or otherwise delete or defeat the critical functions the PCV system performs will be legitimate reason to void.

As more and more GM and Ford dealers sell and install these at the dealership they are getting educated on the benefits. Also, if in the US, it is against Federal law to void a warranty unless the modification or device installed was the direct cause and contributed to the failure in question. As these retain all emission compliance closed systems, and these also improve and enhance the PCV systems functions further protecting the engine, there is no way to legally void your warranty. BUT some ignorant service writers/managers can be difficult. To date there has never been an incidence on any of these systems I like voiding.

Timayz · January 27, 2016

Doesn't look bad at all really. Not like the past non DI motors were shiny clean.

Glava2876 · January 27, 2016

My GMC 6.2 has about 5,500 miles and I installed the Elite 2 Catch Can and Clean-Air Separator yesterday. It had a little oil, but not too bad. Based on this thread, it sounds like I better check it for condensation during the winter months.

The day before, I also installed the same system on my 2015 Corvette Z51 with dry sump and at 1,500 miles it looked dry. Since it has the "summer only" tires, it won't be driven until it is 40F or better, so the condensation shouldn't be an issue.

diyer2 · January 27, 2016

IMO

There are a lot of factors we don't know about to get this result. Oil change intervals, fuel used, ( Top Tier ) driving habits, how much in V4, short trips etc. I still believe this and a lot of the problems brought up on here are not the norm.

GDI Tech · January 27, 2016

Good post diyer, but top tier fuel could only have an impact if it touched the backsides of the valves in a spray that would allow the extra detergents to actually clean, and since no fuel touches the backsides of the valves, this would be impossible. With port injection the fuel constantly sprayed and cooled the valves as the injector was directed at the backsides of the valves:

But with GDI, no fuel ever is on the backsides of the valves. The fuel is introduced directly into the combustion chamber and not until the final milliseconds before spark ignites the mixture, so top tier, any on tank additives, have zero affect and are now a waste of $ when in the past, they were a great option as they have even more additive detergents than standard bulk fuel (all come from the same bulk distribution tanks, the top tier add the extra detergents in the transport tank or at the station of they are delivering to different brand stations).

So when a dealer/automaker/gasoline brand add tells you it helps, that is pure BS as you can easily see.

Now for oil, that does make a difference. Cheap synthetic blend oils like DEXOS blend the dealer uses has a high percentage of conventional mineral oil, and it burns leaving far more ash and residue than a pure synthetic does, so that helps in the severity, but many that have shared pics and that we study have used nothing but say Amsoil or another top rated full synthetic and the deposits are still pretty severe, but less than if a cheap syn blend is used.

Galva, your z51 dry sump will sure show the difference as this video of a Z51 C7 at 5500 miles shows:

Pause this video at the first few seconds and look close, and this owner drained breakin oil out at 500 miles and only ran M1 full synthetic (I like several syn's better than M1)

foo.c · January 27, 2016

My guess is GM recommends Top Tier gas because it makes less soot, but what do they know?

fondupot · January 28, 2016

My guess is GM recommends Top Tier gas because it makes less soot, but what do they know?

No they recommend top tier gas because with motors becoming DI more and more now, they have higher compression ratios. Top Tier gas stations typically have a higher standard of gasoline and will run in the engine better. Top Tier stations like BP, Mobile, Shell, etc.

Generic or non-top tier gas stations may not have the same quality controls as Top Tier stations and may have other contaminates in the fuel. If you are buying fuel from Bob's Fuel Island and Liquor, chances are he isn't getting his fuel from the Top Tier providers. Over time those contaminates can cause harm to a motor.

02Sierra_Mark · January 29, 2016

From GDI's post above, I realize fuel will not wash over the backside, regardless of type. So, I am wondering if E85 would leave more or less deposits than 87/89. I've been using a lot of E85 in my truck for the last year. Hope I'm not doing more harm... Anyone have thoughts on that?

fondupot · January 29, 2016

From GDI's post above, I realize fuel will not wash over the backside, regardless of type. So, I am wondering if E85 would leave more or less deposits than 87/89. I've been using a lot of E85 in my truck for the last year. Hope I'm not doing more harm... Anyone have thoughts on that?

Doesn't matter what kind of gas you use. With direct injection the tops of the valves DO NOT SEE ANY fuel wash. The coking on the tops of the valves comes from oil mist in the PCV system.

02Sierra_Mark · January 29, 2016

Doesn't matter what kind of gas you use. With direct injection the tops of the valves DO NOT SEE ANY fuel wash. The coking on the tops of the valves comes from oil mist in the PCV system.

ah ok...got it...it's the oil mist. Thanks!