[Boilermaker128]

6 years and 1/4 million kilometres on my GM LNF DI, never had a catch can or walnut blasting. I'm sure coking is developing slowly but I haven't noticed any negitive effects so far. Still get my normal 28-31mpg daily driving.

[fzr100098]

Originally Posted by Daves1SS

I've had my mishimoto catch can on mine for 5,000 miles now. I've gone to empty it 3 times now and each time there hasn't been enough oil in there for even 1 drop to come out. Why is it that some of us get oil to empty and some don't? **shrugs shoulders**

Break in

Too many people baby these engines, which always results in more blow by and reduced compression

I've seen it time and time again "do it like the book says" - wrong - ALL engines need a relatively aggressive break in, and it needs to be done quickly

[fzr100098]

Originally Posted by Elite Engineering

The compounds that enter as blow-by are as follows, and GM and others are now returning these in concentrate to the crankcase!!! Crazy!!

It is crazy - and emptying a catch can takes what, 30 seconds?

The one on my jet ski is actually much larger, forced induction motors always have more blow by

[Fraxum]

Here is my question, maybe I missed it, what could be the harm of a catch can?

The OP stated you could be denied warranty claims for having one. GM bought my ZL1 with a catch can back for Stabiltrac problems, definitely not related, but GM or the dealer never mentioned it.

In 3,000 miles I have caught maybe 3-4 oz in my '16 SS. Is this typical?

[SS 1LE]

Originally Posted by Fraxum

Here is my question, maybe I missed it, what could be the harm of a catch can?

There is no harm, it's just that it is not "factory or dealer installed" that they could use against you if they wanted to. All comes down to your dealer. If anything, they should be glad you care enough about your car to have one...

[Fraxum]

Originally Posted by SS 1LE

There is no harm, it's just that it is not "factory or dealer installed" that they could use against you if they wanted to. All comes down to your dealer. If anything, they should be glad you care enough about your car to have one...

I would say most dealers are not like that. Know your dealer before you buy your car. Some are very cool about addon stuff. Ask about those things you want to do before you buy.

[SS 1LE]

Originally Posted by Fraxum

I would say most dealers are not like that. Know your dealer before you buy your car. Some are very cool about addon stuff. Ask about those things you want to do before you buy.

Oh I have a good dealer. They replaced a diff on one of my cars that I flat bedded there from the track wearing Hoosier race tires lol.

[KEL995]

Originally Posted by Elite Engineering

Thought it was time to address the OP on what is occurring in these engines, and how GM has addressed it all:




The response is correct in his description of the dry sump LT1 engine and the wet sump Camaro, and the only separation the Camaro has different aside from the dry sump is it has a "tank" that the cleanside line comes from the drivers side of the air bridge assy, and then runs to the tank and then slits to each valve cover. This cleanside, or fresh side "tank" is empty plastic and has no separation features internally. Also, that tank only helps when crankcase pressure builds and is then forced to seek the path of least resistance, which is backwards out the cleanside lines from each valve cover:


Now, lets address the "returning" what is caught internally to the crankcase/oil pan.


All GDI engines have huge issues with un burnt fuel washdown and contamination as well as the hard abrasive particulate matter that is forced past the piston rings and enters the crankcase as blow-by. In the port injection engines of the past, this was minimal, and the carbon was a "soft carbon" unlike the sand like abrasive baked on crystalline deposits of the GDI engines today so the PCV system would evacuate these effectively from the crankcase before most could settle and mix with the engine oil contaminating it. Now, as GDI introduces the fuel directly into the combustion chamber just before spark ignition, it is at 2,000-3,000 PSI and this forces many times the fuel past the rings. Add that to the 11.5:1 and higher compression ratios of most GDI engines today and much most particulate matter also passes the rings.


When these new engines are being designed to internally separate and return these abrasive and damaging compounds back to the crankcase overloads the engine oils ability to protect like in the past. GM recently dropped engine warranty on GDI engines to 60k miles from 100k miles (should tell a good story) and Ford down to 35k miles. You CANNOT return the concentrated mix of these compounds to the oil w/out accelerating wear and damage over time.


Lets look back first at the history of the PCV system and what id does, and how and why it was implemented and mandated in the mod 1960's.


GM invented the PCV system in WWII to prevent engine damage and crankcase "flash" explosions in the tanks used during the war. Prior to the mid 1960's, all engine used a "vented" system consisting of a "road draft" tube that vented pressure (and oil, etc.) out and it spilled onto the roadway creating the black oil lines down all road lanes in the "old days". Back then the average engine lasted 40-50k miles before a total rebuild was necessary. Valve jobs due to intake valve coking of carbureted engines were done commonly at 20-30k miles as the guides would wear from the coking deposits on the stems was cycled up into the sift guides with each stroke. The PCV system was mandated purely for pollution control as really the first step in what today is a very robust engine. This was only to address the run-ff of the oil spilled from draft tubes..but it was not until afterwards that it was found these same engines, running same oils and drain intervals, were now lasting well over 100k miles. Study of this soon found that the PCV system was now removing the damaging compounds that enter all internal combustion engines as blow-by, before they could settle and mix with the engine oil contaminating it. Now, as GDI is here to stay, the automakers have been struggling to address the issues they have all denied existed until the past few years when they could not explain away what we as techs and engineers were seeing first hand. The wear to valve guides, although much better materials are used, that had disappeared from modern cars for the past 30 or so years with the advent of port fuel injection which washed and cooled the valves constantly with detergent fuels, is now back worse than ever before.


The compounds that enter as blow-by are as follows, and GM and others are now returning these in concentrate to the crankcase!!! Crazy!!


Water: Released during the intense heat and pressure of the combustion process.


Un-burnt fuel: Washes past the piston rings, with GDI much higher than past port injection engines.


Sulfuric Acid: Created as the water mixes with other hydro carbon compounds.


Abrasive soot/ash/carbon: GDI not only produces hard crystalline deposits as abrasive as sand, but the higher cylinder pressures force more past the rings into the crankcase.


Oil mist becomes part of the PCV vapors from the windage present inside the crankcase, and the DOD (displacement on demand) also contributes to the presence of oil mist from the lifters bleeding past, etc.


The oil along with the added compounds that enter as blow-by produce the hard and large deposits on the back sides of the valves. Only properly separating these from the PCV vapors can prevent most of the coking and related issues. And this CANNOT be done internally w/out substantially shortening engine longevity!


The stance that all consumers are as dumb as "sheep" is the way the industry looks at today's buyer, and that mat be pretty accurate as most do not know how to even check their engine oil and other fluids. This along with not doing an oil change by 1000 miles to remove assy debris and wear particles from ring seating, etc. has contributed to engine failure and excessive engine consumption on many of today's engines. Now we cannot stop all of the coking as the EGR emulation function of VVT timing events allows some back filling of burnt gasses to the back sides of the intake valves, and that will always cause some coking, and to add small port injectors in to new GDI engines is not having much positive impact, is allowing greater incidence of pre-ignition (detonation) and greater timing is pulled to address this with knock retard, power and fuel economy suffer as well negating much of the GDI engines benefits.


What about the oil filter? Well, most internal engine wear (app. 70%) is caused by particulate matter in the 2-10 micron size, and as the average oil filter only traps down to 15 microns, most of this is left in the oil to constantly circulate through the engine wearing parts prematurely. Then the fuel and water does not get filtered out, and as the new standards of separating and retaining the oil and these other contaminates internally, this dilution and added contamination also overwhelms the engine oils ability to protect.


Here is an example of GM's latest internal separation and how effective it really is:





Watch the first section several times and pause it to see the valves at almost no miles accumulated. And further, here is a before and after dyno graph of a 2015 LT1 with 20k miles on it before and after a manual intake valve cleaning proving the false statements Tadge and other PR heads have made that they had tested these for hundreds of thousands of miles with NO coking or reduction in performance:








So this is why most GDI engines will only last a fraction of the miles a Port injection would.




All Automakers are down playing the effects and hiding this, but ALL are working overtime to find solutions. The average vehicle buyer will never accept an external system needing to be drained. So only the "enthusiast" will take the time to maintain these solutions.


Anyone doubt the impact? Look at a LY7 3.6L V6 engine at over 120k miles. This was GM's last port injection V6 engine that became the LLT, LFX, and today's LGX:





Now look at a LGX or LT1 V8 engine and see at 5k miles how severe the deposits already are:





And look back at the video on youtube.


Doubt yours look this bad? No need to "take the engine apart", simply take 15 minutes or less and remove your intake manifold and your valves are right there ti see up close and personal.


How do these deposits affect the engine?


First, as the deposits form more severely on the valves closet to the point of ingestion, those cylinders will receive less air charge than the ones furthest with the least, and will run richer than the rest as the upstream O2 senor for that bank will read the entire bank as a whole and the ECU will command the injectors equally. The cylinders with the least deposits will run lean for the same reason as more air charge enters those.


Look back at the picture above of the LY7 port injection engine....ZERO deposits after over 120,000 miles.


Also, highfivemike is 100% correct as all fuels come from the same distribution farms or ports. Shell and other add additional detergents at the bulk tank or at the station underground tanks, bit they are all the same gasoline with Federal mandated minimum detergent amounts. That said, as none of this fuel touches the valves...it has absolutely NO effect on deposits formation nor can any clean the valves as advertised...or the engine. What they do give benefit for is to prevent formations forming in the fuel injectors as the spray pattern and atomization level is easily disrupted from even tiny deposits in the injectors. If this occurs, even greater fuel wash down occurs.


In closing, only you the new vehicle owner can take the proper steps to enjoy long life as in the past, these are not the same as most are used to lasting with little care for hundreds of thousands of miles, these are here to stay and there is no proper solution to date from any automaker aside form some of the Super Cars.


Need further explanation on any of this? Just ask, but educating yourself is the best in understanding what your dealing with here.


Do it once, do it right, Elite Engineering USA

Hearing this from a manufacturer who makes parts to fix the problem is liking asking a supplement company to give credible advice as to if their products work when the FDA doesn't regulate their products.

You are selling a part that voids the warranty.

If chevy has indeed made an engine that blows up before I get my 2-3 years out of the car I will just buy a Nissan or Porsche next time I want a sports car.

I have no doubt your catch can collects oil, but maybe that's part of your design.

I am sure if it is a big enough problem, it will be addressed.

[Speedy1975]

[mikeSS]

Originally Posted by Fraxum

Here is my question, maybe I missed it, what could be the harm of a catch can?

The OP stated you could be denied warranty claims for having one. GM bought my ZL1 with a catch can back for Stabiltrac problems, definitely not related, but GM or the dealer never mentioned it.

In 3,000 miles I have caught maybe 3-4 oz in my '16 SS. Is this typical?

A lot of people (like your self) overestimate a dealerships say in warranty work. They have the rights to make judgment calls on certain stuff.

Once your engine blows, a GM rep gets involved. The GM rep doesn't sell cars, he is here to see what/why something went wrong. Your dealership (or your boy who works at the dealership) is at the mercy of GM.

Now with aftermarket parts install, GM doesn't know the effects of such parts. For all they know you installed it wrong, and its causing damage to your engine. Its not there job to know how aftermarket parts should be installed, or the effects of them.

The fact is you could have warranty problems IF your need a major engine repair and GM doesn't like your catch can.

Most people dont have major failures, so most people are not reporting warranty problems with catch cans.