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Now thats funny right there!! Poor Jerry! I find his posts informative AND entertaining!
Thanks and don't worry about me, I don't have "prepared info!" I have lots of pics from over 40 PDF's I have made on many C7 subjects, usually mods, changing brake pads, installing a battery etc etc.!
I like to write so with one pic can construct a "good logical answer" to questions raised like using a large hose to made a "catch can," as I did above! In fact our Tech Society recently asked if I would write an article for the Monthly Journal on the Welding of Race Cars! Much more fun than many of my other tech papers! Since it is car related some may be interested! http://netwelding.com/Motorsports_Welding_2018.pdf
Have recently written two books for CarTech on the subject that include repairing an aluminum Vette frame. At 75 still able to provide some useful info!
Respectfully... most, if not all, Oil Catch Can threads I've followed start with a discussion of the possible benefits derived from using a catch can to reduce intake valve coking with DI engines. However, they almost always devolve into a series of warnings relative to engine warranties.
What I am hoping to see here (to answer your question) is the experience of someone who has actually taken their catch can equipped C7 in for servicing (of any kind) and been told their catch can voids their warranty.
Since the need to reduce coking of the intake valves seems to be a no brainer and... since the latest 1LE Camaros are catch can equipped ("Chevrolet Performance Positive Crankcase Vent Oil Separator Kit") and... I'm beginning to wonder if the whole warranty issue isn't just an urban myth.
Hence, the topic of this thread: Has anyone actually had their warranty voided because they installed a catch can?
Not even noticed unless major engine failure due to lubrication problems. If your water pump fails and the catch can installation slows down the repair so they can't meet GM guidelines you may hear about it being a problem and some discussion of compensation. Spin a rod bearing or destroy a main bearing and the answer will be we'll see what GM says.
]If the dealer is close, stop by and talk to them, I feel it goes further than a phone call. This is a relationship you want to develop, that's how I view it anyway.[/B] I want this service advisor in my corner if/when I need to bring my car in. I have peace of mind having modded my car, I enjoy the mods and also knowing I can still go to get warranty if needed.
You want to see "the glint in the Service Manager/Advisor's eye" when he says, "No problemo, senor." And you want him to see the "serious as a heart attack" look in yours.
Oil, burnt oil (that hits the hot pistons from a spinning crank,) and other "stuff" comes in the top from the crankcase
Hello,
I hope you don't mind to talk about what comes out of the crankcase and from "where". Perhaps first let us imagine you filled an empty crankcase with liquid water. Even when sitting still at room temperature, some fraction of liquid water is leaving the surface and the mass of water is evaporating. This even happens in the freezer to frozen water, it is why foods "dry freeze" and ice cubes shrink. The 'real reason' that some water molecules are able to leave the liquid or solid total has is because those molecules happened to have a high enough escape velocity. We are able to quantify this as a statistical distribution of relative water molecule velocities on a table/chart and it is in the physics book displayed as such.
As to liquid engine oil, I am going to jump right to the conclusion that liquid engine oil has a partial pressure of it's own, and that some fraction is therefore present in gaseous state as molecules which are leaving the liquid oil, and the effect increases with temperature as more kinetic energy means more leaving molecules. The most basic oil molecule is a straight carbon chain and there is a specific length range where they will tend to lubricative properly or most effectively. Two general things happen to these oil molecules in a running engine.
1. it gets burnt. If the oil molecule arrives in the combustion chamber and reacts with oxygen under high temp/pressure it will form carbon byproducts, many at 'random' (some will have more chance of showing up than others, and nothing is truly random, they are governed by natural law which can be modeled, and we would see that the paths taken are usually the easiest paths and therefore predictable.)
2. It gets chewed up. Smashed between some grinding metal structure at high temperaure and pressure. Notice that temp and pressure are stressing the oil and the input energy is causing it to react and form byproducts in both cases.
Those byproducts are coming from mostly fat-based oil carbon chains, so we expect them to be mostly fat soluble and to dissolve in engine oil. The total engine oil therefore acts as a reserve, or reservoir, for fresh, unchewed carbon oil chains, and a sink for old used up ones. Thing is, there is no way to filter just the poor chains, so instead we have to change the whole oil out each time to ensure we get rid of the poor chains that got chewed. I theorize one day there will be oil chain remodeling systems which fix poor chains as a human body disposes of and replaces red blood cells, eliminating oil changes.
Since we change our oil frequently, poor chain buildup is not an issue. And since it all dissolves in engine oil, there is no reason for them to "hang around" in the active current crankcase gas present. Which by the way, only goes one of two ways.
#1 intake manifold vacuum again. During manifold vacuum the pressure is lower in the crankcase than atmospheric, or should be. This reduces the number of gaseous molecules per unit volume and draws more from the bulk oil, the same way reducing pressure over a volume of water would take up water molecules and speed the escape of new ones from the liquid mass until it was gone. With a low enough pressure it will boil immediately, like blood in outer space, even at freezing temperatures. It is the pressure of other molecules on top of those molecules that causes this pressure. The column of air extending through our atmosphere is the pressure exerted on your body allowing you to draw air into your lungs instead of having it get sucked out into space. With this all in mind, notice that we are intentionally sucking up oil molecules which have left the bulk liquid oil, AND combustion byproducts which consist partially of reacted engine oil and gasoline that have not had a chance to come into contact with and dissolve into the bulk engine oil yet. This is how PCV keeps an engine cleaner: it takes up the byproducts in gaseous state as they pass the rings before the byproducts can dissolve and become part of the engine oil bulk. From another perspective, it lengthens oil change interval slightly. At what cost? Well, cough, the hose that leads off the crankcase is now containing all of those gaseous oil and byproduct molecules, some stop along the way and stick to the hose itself. The rest are taken into the intake manifold where they crust it up, settling there as well, and look at that: the valve is next in line to be settled on. The longer, heavier chains are harder to evaporate, and tend to stick more strongly. So immidiately at the crankcase exit we tend to find this 'clump' or 'crust' or 'glob' of charcoalish material, even in healthy engines that have gone 100k or so, because there is no way to stop oil and combustion byproducts from forming and being taken up into the PCV hose. Its part of how the system works. The engineers design the engine so that the amount or quantity of oil/byproduct that forms is minimal enough that the OEM hose and other components should make the trip 50k or whatever to the first major pcv maintenance schedule. As long as the engine stays healthy. I can say that without asking them because it is common sense.
In #2 the engine is at WOT. Crankcase blowby and therefore byproduct and cylinder filling is near maximal. Notice that it probably has far more byproduct at WOT to deal with. And this is when #1 (the intake manifold suction side, and thus intake manifold and intake valve) is closed at the check valve (pcv valve is shut tight). So at first glance we don't even need to look at this side of the pcv system to know it really has nothing to do with the intake valve getting fouled up, as #1 is shut tight at WOT. However, dig a little deeper. Remember, this is when the most hot active byproducts are forming. That is, they are far more likely to collect and clump in a big mass in the #2 line. #1 is more likely to receive liquid oil (think of a straw, in a drink, and put the straw into the intake manifold suction. It would drink right! So this is a BAD BAFFLE example, allowing liquid oil to touch engine vacuum) and #2 is more likely to receive hot reactive byproducts. Hot reactive byproducts which form deposits. Deposits which can lead to clogged lines, poor flow. And If you have been paying attention I am pretty sure I warned what happens when #2 flow is poor, I will summarize: oil seal damage, increased likely hood of sucking liquid oil is possible.
hope it helps didnt proof read though might be a mistake or two gg!
hope it helps didnt proof read though might be a mistake or two gg!
Hmm, that deserves a...
"Know That You Believe That You Understood What You Think I Wrote, But I Am Not Sure You Realize That What You Read Is Not What I Meant."
PS: Had time to read your post! That's even longer than my usual "long ones!" I can follow most of your thoughts, (although did not like organic chemistry!) but the issue with the "hose accumulating stuff," IMO is not nor has that been an issue in PCV systems. There is a PCV valve that can and does clog and is periodically replaced as it has small passages that prevent high flow when at idle etc so as not to lean out the air/fuel mixture. In fact before 1960 there was no hose! My '56 Chevy V8 had a "road draft tube" that was ~3/4 inch ID and dumped crankcase blowby and whatever onto the road!
The PCV complete system on new dry sumps is complex. Before I added the catch can from my 2014 Z51 I wanted to be sure I was "doing no harm." The one thing it took some time to decipher was the fresh filtered air intake line coming from the engine air intake tube is no longer there! Then where was the replacement air coming from to the crackcase that the PCV system is extracting (as is the oil/air savage pump?) One poster said it was the line going to the dry sump tank from the air intake tube. But that was the line on the 2014 that evacuated the crankcase air pulled into the tank by the oil/air scavenge pump! So I put a Vacuum/Pressure gauge in the hose and at least at idle there is a slight vacuum (1.5 inches of Hg, 0.75 psi) pulling clean fresh air from the engine intake tube into the dry sump tank. Then were is the air going that is pulled into the tank with the pan oil by the scavenge pump? Have no idea- too many lines and no pressure/vacuum data for the new system to decipher what they all do!
However the PCV valve and short PCV hose are there and in the same locations the 2014 Z51 system. Installed the "can" replacing that line and so far find I am collecting (and dumping) only about 25% of the oil I was previously! GM has improved the system to reduce whatever coking is occurring!
Was able to define that line FA brings fresh clean air into the dry sump/crankcase system, at least at idle. So where is the line that deals with the air evacuated by the engine oil/air scavenge pump? Don't know! To many lines and no info to decipher!
Oh I was being very general audience. your question provoked the response but it was not directed at you. It was simply about crankcase contents and how the pcv system works, good archive for this thread title.
...In #2 the engine is at WOT. Crankcase blowby and therefore byproduct and cylinder filling is near maximal. Notice that it probably has far more byproduct at WOT to deal with. And this is when #1 (the intake manifold suction side, and thus intake manifold and intake valve) is closed at the check valve (pcv valve is shut tight). So at first glance we don't even need to look at this side of the pcv system to know it really has nothing to do with the intake valve getting fouled up, as #1 is shut tight at WOT. However, dig a little deeper. Remember, this is when the most hot active byproducts are forming. That is, they are far more likely to collect and clump in a big mass in the #2 line. #1 is more likely to receive liquid oil (think of a straw, in a drink, and put the straw into the intake manifold suction. It would drink right! So this is a BAD BAFFLE example, allowing liquid oil to touch engine vacuum) and #2 is more likely to receive hot reactive byproducts. Hot reactive byproducts which form deposits. Deposits which can lead to clogged lines, poor flow. And If you have been paying attention I am pretty sure I warned what happens when #2 flow is poor, I will summarize: oil seal damage, increased likely hood of sucking liquid oil is possible.
Whoa, KingtalOn! Thanks for the brain cell stimulation! Although most of us are probably familiar with the effects of heat and pressure on liquids in general, I doubt I caught the full gist of your contribution.
One thing it left me wondering is: would our engines be better off in the long run with a vacuum pump running the PCV system rather than manifold vacuum? I realize that would create emission problems but... I wonder if it's been tried.
Whoa, KingtalOn! Thanks for the brain cell stimulation! Although most of us are probably familiar with the effects of heat and pressure on liquids in general, I doubt I caught the full gist of your contribution.
One thing it left me wondering is: would our engines be better off in the long run with a vacuum pump running the PCV system rather than manifold vacuum? I realize that would create emission problems but... I wonder if it's been tried.
Of course if you can avoid sending byproducts from combustion and oil gases into the intake of the engine, and send them somewhere else using an external vacuum source this would be beneficial. Some use exhaust driven PCV to this end but it is difficult to pull off properly. You might think of dry sump tech and nearly every serious race car in an unlimited class. Vacuum pump tech allows the owner to dial up and down crankcase vacuum, even at WOT, which is worth 2-5% horsepower increase for most engines. Forced induction engines tend to benefit more.
the only reason it isn't an ideal solution for those of us who enjoy reliable daily drivers is because a vacuum pump adds unnecessary complexity to our engine, it violates the rule #1 of reliable street cars (KISS). Vacuum pumps wear out and require rebuilding. They contain rotating mechanical parts which can fail like anything else, and it best if it wasn't there to begin with when the added power isn't needed to win a race. In racing you can't give up that 5% but on the street we give up far more than that for safety.
Of course if you can avoid sending byproducts from combustion and oil gases into the intake of the engine, and send them somewhere else ...
the only reason it isn't an ideal solution for those of us who enjoy reliable daily drivers is because a vacuum pump adds unnecessary complexity to our engine, it violates the rule...
With some points raised but no need to ingest the stuff and burn with a very carefully tuned Air/Fuel mixture. As I mentioned and we old timers would remember, before the EPA said enough of that in the 1960s- they used a road draft tube. Recall the one in my ‘56 Chevy V8. It came from a can filled with steel wool, located in the lifter valley thru a 3/4 inch tube that exited with an angle cut level with the sump in the oil pan. All that "stuff" was pulled into the air as you drove! Don’t recall where is was in my ‘51 Ford flathead V8 nor do I remember installing one in the bored ‘51 Olds engine I stuffed in my ‘41 Ford Opera Coupe when I was a teenager. But must have had one!
Also in a race engine would never ask it to use blowby and stuff to burn in the combustion chamber. Would probably do as many racers do and put a Venturi device in the header collector and suck it out with the exhaust. In a street engine those CATs and the EPA would not be happy having that unburned “stuff” going straight to the CATs!
Oh yes, exhaust driven pcv action is ideal for daily drivers. This is my favorite way to handle crankcase evacuation, however it seems time consuming to setup when there is a turbocharger involved in street applications (quiet). The pressure in the exhaust system tends to be quite high on street cars with very well muffled exhaust systems. Supercharged and N/A applications are easy though, when using a properly designed header to suite the application.
Remember that sending oil/byproduct into the intake manifold means that it eventually winds up in the exhaust system anyways. It just has a pass at your combustion chamber and intake valve etc... looking for a place to collect along the way. I highly recommend you skip that part and just send it right out the exhaust to begin with...
Remember that sending oil/byproduct into the intake manifold means that it eventually winds up in the exhaust system anyways. It just has a pass at your combustion chamber and intake valve etc... looking for a place to collect along the way. [/QUOTE]
CATs are designed to eat burned hydrocarbons, they don’t like to eat the unburned “stuff,” poisons the platinum, etc!
If I was going to bypass might as well use a “road draft tube.”
Please don't take this as an invitation to argue the pros and cons of an oil catch can on a DI engine. Been there, done that, ad nauseam.
I'm simply looking to find out if any of you have actually been denied a warranty claim because you installed a catch can. If so, what were the particulars?
Many thanks in advance!
I had the same concern as you so I asked my local dealer who does the free oil changes/ warranty work. They said a can be cause for GM to deny a warranty claim.
As far as taking it off when only necessary I always wondered if the service tech will/can make a note in your file that a can has been installed just for future reference.
I agree with what Foosh said previously. There hasn't been enough hard core evidence that the oil coking is a problem and that the can has been proved to stop the issue. Thus if the can MAY effect my warranty its not worth it at this point. Once my warranty is up then I may decide otherwise
CATs are designed to eat burned hydrocarbons, they don’t like to eat the unburned “stuff,” poisons the platinum, etc!
If I was going to bypass might as well use a “road draft tube.”
Nobody in racing is using a cat that I am aware of. Obviously if you have a catalytic converter the rules are different and it needs to be accounted for. Generally we try to find a way to run without a cat, because its one of those OEM emission control strategies that is only important to the government, for paperwork, numbers on paper that people need to sign, has no real place on a performance vehicle.
I took my heavily modified '13 Camaro to my local dealer to get a tire patched...the porter took it into the garage, and a few mechanics wanted to reflash the ECM because the car was "idling funny". Point is...how many service shops would recognize a catch can as non-OEM? At least in my experience, my local Chevy dealer very likely would not...hence, it wouldn't be an issue. I doubt servicing a Corvette is an everyday occurrence either, so familiarity is lower.
03-17-2018, 03:44 PM
You want to see "the glint in the Service Manager/Advisor's eye" when he says, "No problemo, senor." And you want him to see the "serious as a heart attack" look in yours. 
Although most of us are probably familiar with the effects of heat and pressure on liquids in general, I doubt I caught the full gist of your contribution.
