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As intelligent as Higgs is and so accurate in most all of his posts, this is an area where I am an expert, have been an Automotive Engineer for over 4 decades, worked for GM on the ast, and have worked at a R&D firm that focuses on these very issues and other with GDI engines of today since 2008, I have to respectfully disagree with any that feel the GDI engines of today, especially on these new LT1 and LT4 engines. The amount of premature wear caused by the deposits pulled up into the guide with every cycle, and what we see on very low mileage LT1 engines (lots of videos and pictures on my threads) this is a very real and concerning problem that many choose to ignore, and that is their right. You paid for your car, treat it sa you will, but I see it as a huge serviced to ridicule those that are being proactive.
I will agree that installing a system that does NOT trap nearly all the oil and other compounds baking onto the intake valve backsides will still cause this wear (most cans trap from 14-40% MAX no matter the brand name and truly do little to combat this problem no matter what you see in the can, you need to verify nothing, or nearly nothing is getting past them unlike old port injection engines that kept the valves cool and deposit free) To date only the Elite E2-X and the Colorado speed version have shown to stop it all as so many have posted the before and after results of.
This is my thread so I ask those that are here to disrupt and "wreck it" to please stay out of it from here. Most have been warned by the moderators but still feel a need to come back in and still break the rules. You have been asked nicely by myself, and then from the moderators who come in and have to be bothered to clean it up and delete the rude and disruptive threads. And those that want to learn more just click on my user name and "find more threads/posts" to see all the proof anyone in doubt could have.
If some have technical questions, and want an intelligent discussion with data to back up any pints those are welcome as this is the purpose of these threads. To educate. The GDI V8 engine new for GM and many have spent a good deal of money to buy their dream car. To always come back in and start these attacks, insults, and disruptions helps no one and I cannot understand why some feel it is their goal in life to "burn all the books". argue "the world is flat" so to speak and go out of their way to confuse and disrupt.
These threads are to help members that do wish to learn and become educated and care for their baby the best of their abilities.
So again,
PLEASE stay out of these threads if your goal is just to disrupt.
As intelligent as Higgs is and so accurate in most all of his posts, this is an area where I am an expert, have been an Automotive Engineer for over 4 decades, worked for GM on the ast, and have worked at a R&D firm that focuses on these very issues and other with GDI engines of today since 2008, I have to respectfully disagree with any that feel the GDI engines of today, especially on these new LT1 and LT4 engines. The amount of premature wear caused by the deposits pulled up into the guide with every cycle, and what we see on very low mileage LT1 engines (lots of videos and pictures on my threads) this is a very real and concerning problem that many choose to ignore, and that is their right. You paid for your car, treat it sa you will, but I see it as a huge serviced to ridicule those that are being proactive.
I will agree that installing a system that does NOT trap nearly all the oil and other compounds baking onto the intake valve backsides will still cause this wear (most cans trap from 14-40% MAX no matter the brand name and truly do little to combat this problem no matter what you see in the can, you need to verify nothing, or nearly nothing is getting past them unlike old port injection engines that kept the valves cool and deposit free) To date only the Elite E2-X and the Colorado speed version have shown to stop it all as so many have posted the before and after results of.
This is my thread so I ask those that are here to disrupt and "wreck it" to please stay out of it from here. Most have been warned by the moderators but still feel a need to come back in and still break the rules. You have been asked nicely by myself, and then from the moderators who come in and have to be bothered to clean it up and delete the rude and disruptive threads. And those that want to learn more just click on my user name and "find more threads/posts" to see all the proof anyone in doubt could have.
If some have technical questions, and want an intelligent discussion with data to back up any pints those are welcome as this is the purpose of these threads. To educate. The GDI V8 engine new for GM and many have spent a good deal of money to buy their dream car. To always come back in and start these attacks, insults, and disruptions helps no one and I cannot understand why some feel it is their goal in life to "burn all the books". argue "the world is flat" so to speak and go out of their way to confuse and disrupt.
These threads are to help members that do wish to learn and become educated and care for their baby the best of their abilities.
So again,
PLEASE stay out of these threads if your goal is just to disrupt.
Thanks in advance.
my apologies, not trying to disrupt the thread. not sure why my observations are so contentious. catch cans are very polarizing, lol!
btw, your can may very well get everything, I have not seen a can that does, which makes me form this opinion. if yours does, and you know more about can than me no doubt, then you have what we need.
im not trying to take that or anything else away from you!
Last edited by Higgs Boson; 11-16-2015 at 12:00 PM.
I have another thread to try and get members that are handy to remove their own intake manifolds and post detailed close up pictures and state the mileage on the engine at the time so we can get some long term wide variety of coking levels so all can get a better idea. If we wait and put blind trust and assumptions that there is no issue and then run into the LS7 valve breakage and valve guide wear debacle it is to late for many and they will have soured on their choice to purser what I strongly believe is the absolute best value in a "supercar" today by a large margin, and the solutions to correct these issues is pretty low cost and hassle (other than the draining), and the biggest confusion I think is people do not understand a big brand 15-20% effective can WON't have much effect as susceptible these now are to the coking issue.
Here is a picture of a LS1 with 142,000 miles on, rarely used top tier fuel (but always premium) and this was my very own C5 as an example:
The fuel spray with ONLY the Federally mandated minimum detergent levels, and the fuel spray keeping the valves clean would not allow most any deposits to form period with port injection, so a "catchcan" provided the benefits of reducing oil caused detonation and slowed/reduced the rate of the ring lands building the varnish deposits that restricted the rings ability to move freely and thus over time compound oil consumption issues.
But today 99% of the cans on the market, no matter the brand name allow so much oil and other compounds past them they do little to combat this issue. The better ones like the original E2 by Elite were a much more effective can than most, but as mentioned by others, you cannot expect to address these issues with GDI fueling technology with the "older" technology of 99% of the "catchcans" on the market. For some history on the Elite cans, the original was known for ages as one of the best for port injection engines, and unlike the majority of brands, Elite was always proactive and was always striving to improve as things advanced and the needs increased for ever effective cans, and due to so many builds, turbo and super charging they developed the E2 can with much greater capacity, app. twice the coalescing ability, and dual outlets to allow for a turbo or centrifugal application where the IM is pressurized with boost. Then as GM launched the GDI V8's for 2014, Elite was very proactive in their R&D and it took a ton of $, time, and bringing in outside experts to design the proper system that does stop nearly all of these compounds, and then the over a year of testing and engine tear downs to see the effects as well as the final "independent testing taking months and thousands of miles against the other top selling brands out there to prove first hand they had the solution, with ColoradoSpeed following closely behind with this similar technology instead of the same old technology and designs most all have stuck with ignoring these new engines needs.
I think what so many are stuck on is in the past using the popular cans did help reduce oil ingestion caused detonation and KR, but most that did take their TB off could see plenty of oil getting past so it created on "sour taste" as all claim to be the "best". And then with Elite, some are installing the lower priced early designs that even though can be used, and the E2 will slow the coking rate down for sure, these were designed for non GDI engines and until Elite had gone through all the time, money, effort to prove the effectiveness they certainly were not going to offer the best they had at the time as the best solution at the time, and for those on a budget the lower priced options are attractive if price is the determining factor over the ultimate solution recently released and the Colorado Speed version using the same advanced technology.
So, I hope this also helps those reading better grasp this, and with so many cans to choose from that may do little on any engine to help, I also understand how some are not believers.
Here is a video of a LT1 at 5500 miles. No need to watch the entire video, but pause the first parts and look at the level of coking at these miles. https://www.youtube.com/watch?v=7Pz0zTQ1bz0
Is this the only video you have? It has been posted dozens of times as proof of coking and how to clean.
I shudder each time I see it where the "technician" has a wire brush on the end of a 2' shank in a power drill. The way the shank bounces around in the intake port is certain to discourage anyone from allowing this method on their car.
Here is a video of a LT1 at 5500 miles. No need to watch the entire video, but pause the first parts and look at the level of coking at these miles. https://www.youtube.com/watch?v=7Pz0zTQ1bz0
I have another thread to try and get members that are handy to remove their own intake manifolds and post detailed close up pictures and state the mileage on the engine at the time so we can get some long term wide variety of coking levels so all can get a better idea. If we wait and put blind trust and assumptions that there is no issue and then run into the LS7 valve breakage and valve guide wear debacle it is to late for many and they will have soured on their choice to purser what I strongly believe is the absolute best value in a "supercar" today by a large margin, and the solutions to correct these issues is pretty low cost and hassle (other than the draining), and the biggest confusion I think is people do not understand a big brand 15-20% effective can WON't have much effect as susceptible these now are to the coking issue.
Here is a picture of a LS1 with 142,000 miles on, rarely used top tier fuel (but always premium) and this was my very own C5 as an example:
The fuel spray with ONLY the Federally mandated minimum detergent levels, and the fuel spray keeping the valves clean would not allow most any deposits to form period with port injection, so a "catchcan" provided the benefits of reducing oil caused detonation and slowed/reduced the rate of the ring lands building the varnish deposits that restricted the rings ability to move freely and thus over time compound oil consumption issues.
But today 99% of the cans on the market, no matter the brand name allow so much oil and other compounds past them they do little to combat this issue. The better ones like the original E2 by Elite were a much more effective can than most, but as mentioned by others, you cannot expect to address these issues with GDI fueling technology with the "older" technology of 99% of the "catchcans" on the market. For some history on the Elite cans, the original was known for ages as one of the best for port injection engines, and unlike the majority of brands, Elite was always proactive and was always striving to improve as things advanced and the needs increased for ever effective cans, and due to so many builds, turbo and super charging they developed the E2 can with much greater capacity, app. twice the coalescing ability, and dual outlets to allow for a turbo or centrifugal application where the IM is pressurized with boost. Then as GM launched the GDI V8's for 2014, Elite was very proactive in their R&D and it took a ton of $, time, and bringing in outside experts to design the proper system that does stop nearly all of these compounds, and then the over a year of testing and engine tear downs to see the effects as well as the final "independent testing taking months and thousands of miles against the other top selling brands out there to prove first hand they had the solution, with ColoradoSpeed following closely behind with this similar technology instead of the same old technology and designs most all have stuck with ignoring these new engines needs.
I think what so many are stuck on is in the past using the popular cans did help reduce oil ingestion caused detonation and KR, but most that did take their TB off could see plenty of oil getting past so it created on "sour taste" as all claim to be the "best". And then with Elite, some are installing the lower priced early designs that even though can be used, and the E2 will slow the coking rate down for sure, these were designed for non GDI engines and until Elite had gone through all the time, money, effort to prove the effectiveness they certainly were not going to offer the best they had at the time as the best solution at the time, and for those on a budget the lower priced options are attractive if price is the determining factor over the ultimate solution recently released and the Colorado Speed version using the same advanced technology.
So, I hope this also helps those reading better grasp this, and with so many cans to choose from that may do little on any engine to help, I also understand how some are not believers.
respectfully its time to stop posting pictures of BMW engines, engines with port injection, and the same video. every carbon build up thread has this posted multiple times.
I really like the idea of this thread, this GDI problem really has my interest.
a picture was posted in the last page of a intake valve of a LT1 with 12k miles. It appears to have some black stuff (carbon ?). Would like to get your thoughts on that picture.
Mine has 1500 miles on it, Its getting a supercharger, headers, meth and FSP catch can system. I will pull the intake thanksgiving weekend and take pictures, its not hard to do.
respectfully its time to stop posting pictures of BMW engines, engines with port injection, and the same video. every carbon build up thread has this posted multiple times.
I really like the idea of this thread, this GDI problem really has my interest.
a picture was posted in the last page of a intake valve of a LT1 with 12k miles. It appears to have some black stuff (carbon ?). Would like to get your thoughts on that picture.
Can you point out where I have posted any BMW pictures these last posts? Only LT1 and LS1 pictures. The video is a 2014 wet sump Z51 C7.....I have a thread dedicated just to those who remove their IM and take pictures along with the mileage, and many of the pictures (most) are late model GM GDI engines. The reason other brands are posted is to show GM is not alone, ALL GDI engines have these issues and not a single one has solved it aside form the air/oil separating can equipped "super cars".
As far as the 3 year dyno testing test and summary, until we can show the same on a C7 (have yet to find someone willing to commit their car to a long term test) we can only go off of other late model high tech GDI engines that have. No matter how some want to believe that the new GM GDI V8's have somehow magically immune to these issues that affect ALL auto makers, 4 stroke outboards, 4 stroke snowmobiles, etc. these are the most accurate examples to judge by. So these threads asking others to actually remove their intake manifolds (very easy and involve no "tearing apart" the engine) and help in documenting what they find and the miles. And we really need to see each port as well as a shot back far enough to show they are actually showing pics of a LT1 or LT4 engine.
I also have posted links to others doing actual manual cleanings on their C7 engines also as more threads pop up from others. The poster below should be a welcome addition as well with what he can share.
The picture posted your referring to shows a very wet looking oil deposit building and appears to be not as "baked on" by the much higher heat these LT1 and even higher LT4 engine valves operate at now the fuel spray is not cooling them with a constant spray. If that one is at 12k miles (would really like to see pics of ALL the valves as the furthest ports from the ingestion point, which is at the very front side of the intake manifold will always show more severe build up than those furthest, or at the rear of the engine....and this causing uneven A/F ratio between them as they coke at uneven levels. Those with more build up will run richer than the furthest ones with less as less air is entering the combustion chamber yet the O2 sensors from each bank only measure the exhaust and un-burnt fuel as a combined total of the output, and thus the injectors are commanded to deliver an equal amount to each cylinder even though they each will eventually need differing amounts based on the actual airflow into each individual cylinder.
Originally Posted by Steven Popham
Mine has 1500 miles on it, Its getting a supercharger, headers, meth and FSP catch can system. I will pull the intake thanksgiving weekend and take pictures, its not hard to do.
Excellent Steven! This is what we need more of or the assumptions will continue. We really need to see actual examples and make sure to post your miles at the time.
Thanks in advance! No one wants to find out several years down the road the C6 Z06 issues that finally have made real headlines and getting action. These can be headed off early and owners educated far more accurately.
Can you point out where I have posted any BMW pictures these last posts? Only LT1 and LS1 pictures. The video is a 2014 wet sump Z51 C7.....I have a thread dedicated just to those who remove their IM and take pictures along with the mileage, and many of the pictures (most) are late model GM GDI engines. The reason other brands are posted is to show GM is not alone, ALL GDI engines have these issues and not a single one has solved it aside form the air/oil separating can equipped "super cars".
As far as the 3 year dyno testing test and summary, until we can show the same on a C7 (have yet to find someone willing to commit their car to a long term test) we can only go off of other late model high tech GDI engines that have. No matter how some want to believe that the new GM GDI V8's have somehow magically immune to these issues that affect ALL auto makers, 4 stroke outboards, 4 stroke snowmobiles, etc. these are the most accurate examples to judge by. So these threads asking others to actually remove their intake manifolds (very easy and involve no "tearing apart" the engine) and help in documenting what they find and the miles. And we really need to see each port as well as a shot back far enough to show they are actually showing pics of a LT1 or LT4 engine.
I also have posted links to others doing actual manual cleanings on their C7 engines also as more threads pop up from others. The poster below should be a welcome addition as well with what he can share.
The picture posted your referring to shows a very wet looking oil deposit building and appears to be not as "baked on" by the much higher heat these LT1 and even higher LT4 engine valves operate at now the fuel spray is not cooling them with a constant spray. If that one is at 12k miles (would really like to see pics of ALL the valves as the furthest ports from the ingestion point, which is at the very front side of the intake manifold will always show more severe build up than those furthest, or at the rear of the engine....and this causing uneven A/F ratio between them as they coke at uneven levels. Those with more build up will run richer than the furthest ones with less as less air is entering the combustion chamber yet the O2 sensors from each bank only measure the exhaust and un-burnt fuel as a combined total of the output, and thus the injectors are commanded to deliver an equal amount to each cylinder even though they each will eventually need differing amounts based on the actual airflow into each individual cylinder.
Excellent Steven! This is what we need more of or the assumptions will continue. We really need to see actual examples and make sure to post your miles at the time.
Thanks in advance! No one wants to find out several years down the road the C6 Z06 issues that finally have made real headlines and getting action. These can be headed off early and owners educated far more accurately.
You have in the past posted pictures of BMW engines, and probably Audi engines(cant remember) . i figured you would post them again in the near future.
pretty well know fact those engines were some of worse cases of carbon build up. when you google "carbon build up on valves" you manly get audi and bmw results. So when you post a picture of a audi at 20k miles, and its got a lot of carbon build up. one could argue a basic logic statement. being that all GDI engines are prone to build up, the LT1 is GDI therefore its going to have this problem. the statement is may be true. We don't know at what rate the build up happens.
again look forward to seeing more pictures. very interesting topic
Nobody is an expert in this area. I have yet to see any horrible coking.
Here is a picture of mine after 12000 miles.
Everyone knows Higgs redirects the debate to an unrelated and highly personal level. Therefore, just left him go and chose not to wrestle in the mud with him.
Russ, that pic sure shows a puddle of oil in there as well, and as the deposits are wet more than baked on dry as in most pictures, is yours by chance a 2014 dry sump car? If so, you may be able to get the drysump tank upgrade under warranty to the new design for 2015 and up with the far more effective cyclonic separator included. Those are the wettest most oil soaked I have seen to date, and that excess amount of oil is entering from somewhere in the intake air charge or possibly through the valve guide and seal, but that would be earlier than any guide worn out of spec at 12k miles. Generally it is not until 20-25k miles we see them worn excessively. Do you have pics of the rest of the valves? Are they all wet like that with oil pooled?
Have several threads on the intake valve coking issues with the LT4, so will make this one for the LT1.
This video does a good job of showing you what the issues are, the causes, and better understanding your new generation engine and how to prevent issues down the road. Look close and pause the video several times to see just how rapidly the intake valves are building the deposits.
Now, much of this is redundant if a member searches, but I will cover it all here for the C7 crowd in one thread.
Prior to 2014, all GM V8 gasoline engines were port injection. This constantly showered the intake valves with detergent fuel (ALL gasoline in the US must have minimum mandated detergent content to keep valves clean from back prior to port injection when carbureted engines experienced this coking causing wear to valve guides and stems resulting in a needed valve job by 40-50k miles) and when the industry migrated to the port fuel injection most have grown up with valve jobs went the way of the dinosaur, that is until GDI came onto the scene to be able to meet Federal emissions and CAFE fuel economy standards. So, here is a diagram of how a port injection fuel system kept your intake valves spotless longer than the life of the engine, and why most do not remember when a valve job was part of owning a car
This fuel spray kept the valves cool and clean and even after 100-200k miles, a port injection engines intake valves will never have deposits on then, and therefore the valve guides and stems rarely saw wear (unless a machining error as the LS7 is known for in some instances) and the main reason for a "catchcan" was to stop the oil ingestion that caused detonation, clogged ringlands, and other issues, but never contributed to premature wear of internal engine parts and the degradation of power and economy over time like we see today with GDI.
Below shows how now, top tier fuel does nothing to improve any part of the injection or fuel system, and the fuel never touches the valves
There are many advantages to GDI vs PFI, and this is mainly due to the near elimination of detonation (pre-ignition, Knock, etc.) as the fuel no longer is present through the entire intake and compression stroke where any glowing carbon spec or hot point in the combustion chamber could pre-ignite the A/F mixture. Now the fuel is not introduced until the final 10% or so of the compression stroke, and it is present only milliseconds (most of the combustion process occurs before the fuel can even touch the piston top) so we can now see far higher compression ratios, lower octane fuels, less emissions, and better fuel economy. The fuel injectors now operate at 2000 plus PSI vs the 45-55 of old PFI, so they cannot easily form ANY deposits. This renders any fuel additives, top tier fuels, etc. useless and a waste where they were of great benefit to the PFI engine.
The downside is with no fuel to keep the valves cool and deposits free, we now have a far greater issue that back in the 60's and 70's when carbureted engines had the coking and wear issues from it. AT least then some fuel cooled and cleaned/slowed deposits. Now there is zero.
So, a valve that would have looked like these pictures of a PFI engine at say 142000 miles (actual mileage of the LS engine in these pictures)
now will look like this in as little as 40k miles:
These deposits are caused by more than just the oil mist present in the intake air charge, there is also several other damaging compounds that enter the crankcase as blow-by, and what you see is only part of the issue. Over time, as these hard abrasive pieces break loose, smaller ones can be forced between the piston and cylinder wall causing scouring and larger ones can get trapped between the valve and seat causing piston to valve contact and a bent valve or worse:
Look closely at the valve above, and you can see on the left portion of the stem where the tulip meets a large chunk broke off and caused the damage. The owner bringing the car in to the dealer they did diagnose it right away so a good amount of driving was done after this occurred and you can see the additional build-up over where the chunk broke off.
Now, anyone with a 2014 or 2015 LT1 have doubts this is occurring in your engine? It only takes 5-10 minutes and minimal tools to remove your intake manifold and look at YOUR valves up close and see the severity at the miles you have on yours.
Now, how to prevent this?
The "catchcans" of the past that worked well with a PFI engine, only trapped 15-50% or so of this oil mix that bakes onto the valves so they may slightly slow the coking, but will do little to stop it. You must use one of the very few that catch and trap 95-08% of this mix, and those are true air/oil separation devices. ColoradoSpeed and Elite Engineering having two of the most effective period currently on the market (extensive test results available to any that wish to see how the other "catchcans" stack up).
You must stop as much of this as possible.
Now, looking around I see several well intended solutions, that are not well thought out, and the most common is to delete the PCV system, and just rout your clean and dirty side lines into a tank with breather, or worse, open hoses near the ground (where one due to the Venturi effect will suck up dust and dirt directly into the tank and the engine).
The PCV system does far more than satisfy emissions. Back when the Fed mandated the PCV system in the mid 60's, it was rare for an engine to go much over 50k miles before excessive wear of all internal parts resulted in an entire rebuild being needed. And even though the PCV system was mandated for emissions alone (before that draft tubes were the norm, similar to the breathered Tanks seen today) but it did not take long for the industry to see these same engines were going 100-150k plus miles with little internal wear. Studying this found that the PCV system was constantly removing the damaging combustion by-products from the crankcase as soon as they entered and were still in a gaseous state. If allowed to settle, these mixed with the oil contaminating it and causing wear and failure eventually. The PCV system was removing these allowing the oil to stay cleaner longer, and the damaging compounds to accumulate at a minimal amount. So, defeating your PCV system is a sure way to cause a shortened engine life and accelerated wear. The compounds causing this wear and damage are as follows:
Water vapor
Unburnt fuel
Abrasive soot and carbon particles
Sulfuric acid, and more.
70% plus of internal engine wear is caused by the particles in the 2-5 micron size, and as your oil filter can only trap down to 15 microns in size, if these are allowed to accumulate in the engine oil and crankcase, you are drastically shortening the life of your engine. ANY defeat of any critical function of your PCV system is going to allow this, and/or worse. Allowing pressure to build and vent is also damaging over time to the rings, ringlands, and cylinder walls due to "ring flutter" and other damage caused by ring instability, so you want to pull vacuum/suction at all times, and NOT ever vent pressure as it must first build until it can vent, and no good comes from crankcase pressure.
So, the systems that deal with this properly are addressing the dirty, or foul side with a truly effective separation device, and w special separator that is used on the "clean, or fresh side" and add a secondary evacuation suction source for when the engine is under acceleration and no intake manifold vacuum is present.
I'll stop here for now and invite questions and discussion on the GDI engines in general, and more specific GM's and what they have done to reduce the ingestion, and why this affects EVERY single GDI engine made in the World from every auto maker. Understanding and making the correct emissions compliant, not effecting warranty changes to ensure you get the longest enjoyable life out of these awesome engines.
There are certainly two camps when it comes to GDI engines and carbon build up on the intake valves. One camp believes it's a myth and not an issue. The other believe it contributes to premature wear of the engine creating loss of power, wearing of intake valves which leads to rough running engines and shortened of engine life.
I fall into the latter camp and therefore believe it's an ounce of prevention to install a catch can. My thought is, a catch can doesn't harm anything and if it turns out GDI engines are not prone to carbon build up over time, no harm no foul by having one installed. However, if it turns GDI engines are negatively impacted by carbon build up than I'm inoculated against it.
There are certainly two camps when it comes to GDI engines and carbon build up on the intake valves. One camp believes it's a myth and not an issue. The other believe it contributes to premature wear of the engine creating loss of power, wearing of intake valves which leads to rough running engines and shortened of engine life.
I fall into the latter camp and therefore believe it's an ounce of prevention to install a catch can. My thought is, a catch can doesn't harm anything and if it turns out GDI engines are not prone to carbon build up over time, no harm no foul by having one installed. However, if it turns GDI engines are negatively impacted by carbon build up than I'm inoculated against it.
there is proof that GDI engines are prone to carbon build up on the back of the valves. plenty of documentation on this.
I have done a lot of outside research on this topic. Even asked a few well known youtube mechanics (in videos about this). Everyone says GDI is going to have build up, but its not going to be noticeable until higher mileage. 50k+ miles.
I feel Cospeed is being extreme on this problem. saying that my valves will have a lot of carbon build up at 20k miles. Which i cannot see GM producing a engine that starts to have some what major problems at 20k miles.
My whole thing is at what rate are these LT1 engines going to build carbon. there is very little data on that right now.
direct injections by design are of course going to have higher carbon buildup on the stems of the valves then port injection engines (pretty simple since port's have gas shooting on the valves during in intake stroke pretty simple concept to grasp) I haven't read thru all these post's, quite frankly its a little too much banter for me to take in,lol.
For guys who have been in the industry for years like me its just a common issue, working on diesel engines from time to time Ive seen this before and of course on the carbureted cars of years past the fuel was pretty atomized and didn't clean much off the valves back then either. But lets add our pcv system and the amount of actual oil that passes by it into the intake into the equation and weve got a real problem.
I cant speak to what brand catch can will do the best job and wont speak to the debate about "if it wont catch all then whats the point" either.But oil on the plugs for no other reason is bad, not to mention the valve train issues if a valve eventually sticks do to too much crap on it. It only takes a valve one time to slightly stick and then nag you are in trouble especially on and interference engine.
And as an ASE certified master technician of 20 years and also the L1 certification I do kinda know what works in the "REAL WORLD" and not just theory,,,,, having said that I had a catch can on my C6 and now C7 both from the same folks and did see a better way of routing/adding to that design to pick up better filtering/oil catching and Grabbing that or any oil before it gets on the valve stem and builds up or the plugs that eventually will give you issues is just bad. How bad? I don't know. How long can it go? I don't know. Does it eliminate 100%? I don't know. but why not try and get rid of that stuff?
Side note: I do also know some of the best products for "cleaning" up the valves as well, U don't need a tear down just the right cleaning stuff going simply thru a good manifold vacuum source once a year or so.
So I would say a properly installed catch can doing a good job and proper valve cleaning once a year after 3k miles or so is going to all but eliminate this issue,
And by the way good fuel injector-fuel system maintenance also which is 4 fold (this is what we have done for years) will do the trick.
1. new fuel filter
2. Fuel injector cleaning via a "charged device" straight thru the main fuel line hose (on the vette its the one on the drivers side on top of the valve cover) Not just dumping something in the line from oreillys is gonna do it.
3. An intake valve cleaner that's distributed thru the intake via a manifold vacuum source under higher rpm really does a good job
4. a fuel additive right after that that does fuel line cleaning.
Do this and I think if you inspected your valves after you would be shocked.
Ive used a couple companies products that do this but just look for a multi-step fuel system cleaning (or a shop who does this). . Food for thots, not looking to get in the debate. paul
for me, it's not about the valves or just having some oil in the intake manifold, i have the LMR vta setup because I don't want any oil or anything else diluting my oxygen/fuel mixture in the combustion chamber.
A simple water type injection system should take care of it
That pic Russ put up doesnt look bad at all as far as carbon. Maybe its the pic or my poor eyesightbut is that valve even sealing all the way around?
That and quit babying these things
When I used to drive my 5.3 hard never got anything substantial....as it aged drove it easier. Floor it now and theres a large carbon cloud behind me. "Saving them" and lugging them around in 6th at 30mph does your engine no favors in fact does more harm them good.
Just my amateur opinion
Excellent posts by a few. I want to point out I am not "selling" anything as I work full time as an Automotive Engineer for a R&D engineering firm that specializes in just these issues, and has since 2008 when they were first contracted to study GDI in general. the issues, causes, and if possible find solutions. I am not a day to day mechanic, but a member of SAE (International Society of Automotive Engineers). The firm also does direct and subcontracting work for either tier one or tier two suppliers to not only the big 3 here domestically, but Euro and Asian as well. In fact, all current GM V6 GDI engines now use some of this firms designs. So, this is my area of expertise, and my goal is to get more involved to study and share what they are seeing (not assumptions, etc. but real pictures of all valves and the miles driven, and as cuisinartvette states, driving them super easy certainly does not help.
I will also state that the PCV system does far more than meet emissions requirements.
It also performs several critical functions that of defeated, or deleted as the "tanks/breather" systems do, will result in accelerated wear and shortened engine life unless the oil is changed after every outing as well as can cause instability of the piston rings by allowing crankcase pressure to first build and them vent instead of pulling suction at all times on the crankcase assisting ring seal and stability.
A little history:
Prior to the early 1960's all cars and trucks had no PCV system. They operated under the assumption that crankcase pressure could just be vented, and "draft tubes" were utilized and any old timer can remember the dark oil strip down each lane of the road in those days, and engines rarely lasted more than 40-50k miles if that before needing a complete rebuild. And that was changing oil at the recommended 1500 mile interval. When the PCV system was Federal Gov mandated the PCV system implemented Nationwide, in the years following an unexpected benefit was discovered. These same engines, using the same oils, now were lasting 100-150k plus miles before needing a rebuild. It took several years of study to determine that the PCV system was removing the damaging compounds that are byproducts of the combustion process (entering as blow-by that all engines have to this day) and these damaging compounds were being evacuated, or "sucked out" from the crankcase with fresh filtered air replacing them. Fresh, clean air in one bank, and dirty foul vapors out the opposite so most was being removed before it could settle and mix with the engine oil (anyone with a new GDI engine probably notices your oil gets dark far sooner than in the past...this is the abrasive carbon and soot articles entering that are too small for the oil filter to trap. The oil filter can only trap down to app 15 microns in size, and most of the internal engine wear is from particles far smaller than this) and the results while not at all expected from a "pollution control" device, it soon became evident why, and the study of proper crankcase evacuation (not venting pressure) an important part of engine system design. So, if you defeat these processes as a "tank/breather" does by connecting the fresh/clean side of the engine with the foul/dirty side, you are only allowing pressure to vent once it builds, and are also allowing almost all of the water, un-burnt fuel, sulfuric acid, soot and carbon, etc. to remain in the crankcase and quickly condense and accumulate mixing with the engine oil as well as eliminating the ring sealing and stability benefits of pulling suction on the crankcase. This contributes to even more blow-by and none of this is good. This does stop all oil ingestion though, but at the sacrifice of the engines longevity and illegal on the road on all 50 States (and i am not here to preach anyone is bad for violating the law..that is their choice).
So, there is little as far as training on anything PCV related now days, but this basic training video does help people get the basics:
So, those that are polite and want to learn, and share actual data, I thank you and ask any to take the time to simply remove their own intake manifold and take some pictures and share the mileage your at.
For those that seem to have made this their mission in life to discourage others from or prevent this information from being shared, I can't for the life of me understand the motivation. Why not take part in this and examine and share what your own engines vales look like and the mileage on it? And it is common sense that of the LS7 engine has class action law-suites (also some I read have included the C7 Z06) for valve guides worn out of acceptable spec at 15-20k miles with zero coking/deposits, the abrasive deposits seen in every picture to date even at 2000 miles, are also going to wear (but for different reasons). Most here as member's have spent a good deal of $ related to their income/net worth, (some it's a drop in the bucket) and spending $thousands on aftermarket wheels for looks and other appearance mods, why is it you are dead set on them not spending a small amount in comparison on something that can absolutely have no downside, and only advantages whether you believe deposits on the valves cause air flow disruption and wear or not. Oil is never good in the intake air charge, and with a GDI engine it is the main cause of detonation and knock retard.
The engineers at GM are among the best in the World, and the LT series of engines is amazing (as are the LLT/LFX, 2.0T, etc.) and GDI is here to stay. They designed those chambers, the valve size and shape, port size and shape, seat grind angles, etc to be as efficient as is possible in a mass produced engine, and any disruption will have a negative effect on the airflow.
So, again I ask that those that are against this, you have said your piece, and I ask you again to please stay out of the discussions so they can be beneficial for those that do wish to learn and care for their investment the best way possible, and again, your welcome to remove your intake manifold and take detailed pictures of ALL your valves and post them along with the mileage on the engine at the time, but do not continue your mission to disrupt.
These cars are to important to most of us and many do want to learn and share. That is the only way we are going to get more accurate, real information from the field and not the lab.
Those that have an understanding and are contributing positively to these discussions I thank you. And in closing, as far as GM releasing an engine with these issues, they are no different than any other automaker in the World and with the mandate to meet CAFE fuel standards, they have been forced to. It is NOT GM doing anything bad. And many of the pictures I show in other posts are late model GM GDI engines in addition to the LT family.
Oh, and look at the picture of the oily valve closely. It is closed all the way and has a puddle of oil behind it. Study that picture closely. There is a reason I would like the person who took the picture to chime in with more and more info to determine why there is so much oil and why it is so wet instead of the dry baked on deposits we generally see.
sounds like a lot of agreement with just a thot/guy or 2 trying to say his way is the best way and that's that. while another thot/guy is just making suggestions to help us all out which I can appreciate the knowledge and thread for that a lot. I'll make up my own decisions based off what I know and read, and thanks for the thread **Things we agree on that seem pretty simple to grasp below,
1. Oil in the intake is bad 2. Doing things to eliminate that is good 3. Eliminating certain systems on the car that are there for you own ENGINE LIFE bad 4. PCV system should stay pretty intact/similar to original (don't eliminate it completely or don't pinch down the vacuum pressure or flow rate) good
5.
I guess the thread kinda turned a different direction, bUT remember these threads are for free public consumption and have to be taken with THAT IN MIND. Its easy to get all bent out of shape over something as trivial as a thread posted by a guy from another state while sitting in your lazy boy relaxing with a cold beer on a really nice fall evening. I mean the nerve of the guy right? LOL
11-16-2015, 11:32 AM
