DIY: LTI intake valve cleaning/cleaning deposits
06-20-2016, 12:07 PM
#41
Instructor
I have ordered a 2017 NON-Z06, NO dry sump Corvette. 1. Do I require the dual exit port catch can? 2. Are installation instructions included? 3. Can the equipment be easily removed for CA CARB inspection?? 
06-20-2016, 02:28 PM
#42
DISCLAIMER: This DIY guide has been put together using knowledge from various third party sources, and demonstrated on one vehicle. It is not endorsed or property of this forum or myself in any way/shape/form. This is simply more information for those who are curious about the cleaning process. Neither this forum nor myself are liable for any damages that are incurred as a result of using this guide. The end user (you) assume all risks to you/your car/your environment by using this guide. E.g. you take the risk of breaking your car/voiding your warranty by using this guide.
I also do not endorse any of the products used in this DIY, purely one man’s tools and opinions.
Now let’s get to it. I want to give thanks to the following as this would not have been possible without the information they provided:
Theta's excellent DIY guides in the stickies section.
RX for their videos showing their intake valve cleaning
coSPEED2 and other vendors for bringing this issue to light
user Wormwood for his advice/expertise as he had completed this before me
various other users and threads detailing the BMW “walnut shell cleaning”
The C7 Z51 is the second GDI (Gas direct injection) engine I have had. I previously had a VW that I completed a similar cleaning before. Knowing that, I immediately installed Elite Engineering’s clean oil separator and catch can upon picking up my car at the dealer last year. I also immediately drained all the oil and completed a new oil change and performed a cleaning of intake air tracts at that time. My C7 is a weekend car, and only very few miles and is not tracked. I used a boroscope a few months ago and confirmed that my intake valves were pretty clean and did not need a cleaning right now.
My friend bought his C7 Z51 shortly after I did. His was used and came with 6k miles. At the time he bought it, it did not have a catch can or oil separator installed, and records showed that it received the first oil change at around 1200 miles. He installed the same catch can and air separator shortly after buying the vehicle. He was worried about valve coking issue after reading several threads, and proceeded to our local Chevy dealer to inquire about induction cleaning service. When he talked to the service advisor, they looked at him if he had grown two heads. One of the techs said that they could spray a cleaner into the intake and clean it that way, but that he would be charged $400. My buddy at this point approached me for help.
There are differing opinions on how much this affects performance/efficiency and what type of cleaning is warranted, I am not hear to argue those issues. There are those who have just sprayed/poured cleaner into their manifold and then crank the engine. This type of cleaning causes me nightmares as I can see countless chunks/sludge and deposits making their way past the intake valves and into the chambers. I put together this DIY for those who wanted to know more about the process of cleaning the valves. This was done on my buddy’s 14 Z51, but I can see the same thing being applied to the wet sump engine as well.
I also do not endorse any of the products used in this DIY, purely one man’s tools and opinions.
Now let’s get to it. I want to give thanks to the following as this would not have been possible without the information they provided:
Theta's excellent DIY guides in the stickies section.
RX for their videos showing their intake valve cleaning
coSPEED2 and other vendors for bringing this issue to light
user Wormwood for his advice/expertise as he had completed this before me
various other users and threads detailing the BMW “walnut shell cleaning”
The C7 Z51 is the second GDI (Gas direct injection) engine I have had. I previously had a VW that I completed a similar cleaning before. Knowing that, I immediately installed Elite Engineering’s clean oil separator and catch can upon picking up my car at the dealer last year. I also immediately drained all the oil and completed a new oil change and performed a cleaning of intake air tracts at that time. My C7 is a weekend car, and only very few miles and is not tracked. I used a boroscope a few months ago and confirmed that my intake valves were pretty clean and did not need a cleaning right now.
My friend bought his C7 Z51 shortly after I did. His was used and came with 6k miles. At the time he bought it, it did not have a catch can or oil separator installed, and records showed that it received the first oil change at around 1200 miles. He installed the same catch can and air separator shortly after buying the vehicle. He was worried about valve coking issue after reading several threads, and proceeded to our local Chevy dealer to inquire about induction cleaning service. When he talked to the service advisor, they looked at him if he had grown two heads. One of the techs said that they could spray a cleaner into the intake and clean it that way, but that he would be charged $400. My buddy at this point approached me for help.
There are differing opinions on how much this affects performance/efficiency and what type of cleaning is warranted, I am not hear to argue those issues. There are those who have just sprayed/poured cleaner into their manifold and then crank the engine. This type of cleaning causes me nightmares as I can see countless chunks/sludge and deposits making their way past the intake valves and into the chambers. I put together this DIY for those who wanted to know more about the process of cleaning the valves. This was done on my buddy’s 14 Z51, but I can see the same thing being applied to the wet sump engine as well.
We are about to do the same on a 2013 GTI at my shop.
06-20-2016, 02:55 PM
#43
Melting Slicks
Cleanside replaces stock oil fill cap, cross over line form valve covers comes with additional OEM snap on connectors, and then it is just vacuum caps you install and can take back off to revert to stock.
Only one hole to drill into coupler that attaches main air bridge assy. to the throttle body, and that can easily be plugged.
This is slightly different as it is a 2014 up truck LT engine here, but same install.
Please post pictures of what you find. We have found soaking the valves first for 15 minutes plus w/CRC or Seafoam cleaner helps loosen them. They are rock hard and crystalline so make sure the ports your cleaning the valves are closed completely so no debris gets past.
PM me for any help or tips.
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Tron1 (06-21-2016)
06-22-2016, 03:47 PM
#44
Melting Slicks
Need to keep this bumped up for all to read and learn. Would be a great sticky.
08-15-2016, 06:52 PM
#45
Instructor
Steps to reduce coking on intake valves, as I understand it include:
1. top quality tier 1 gas
2. running the engine more aggressively, keep revs up
3. top quality hi performance synthetic motor oil (i.e., Amsoil, Redline or ?? what would qualify) Mobil 1 5w-30 meets the GM recommendation but I know it as a mid level oil)
4. Elite catch can as described and sold by COSPEED.
If I have left any pertinent info out please make additional comments. I look forward to more feedback on this thread.
1. top quality tier 1 gas
2. running the engine more aggressively, keep revs up
3. top quality hi performance synthetic motor oil (i.e., Amsoil, Redline or ?? what would qualify) Mobil 1 5w-30 meets the GM recommendation but I know it as a mid level oil)
4. Elite catch can as described and sold by COSPEED.
If I have left any pertinent info out please make additional comments. I look forward to more feedback on this thread.
08-16-2016, 11:09 AM
#46
Instructor
bump
08-16-2016, 01:28 PM
#47
Steps to reduce coking on intake valves, as I understand it include:
1. top quality tier 1 gas
2. running the engine more aggressively, keep revs up
3. top quality hi performance synthetic motor oil (i.e., Amsoil, Redline or ?? what would qualify) Mobil 1 5w-30 meets the GM recommendation but I know it as a mid level oil)
4. Elite catch can as described and sold by COSPEED.
If I have left any pertinent info out please make additional comments. I look forward to more feedback on this thread.
1. top quality tier 1 gas
2. running the engine more aggressively, keep revs up
3. top quality hi performance synthetic motor oil (i.e., Amsoil, Redline or ?? what would qualify) Mobil 1 5w-30 meets the GM recommendation but I know it as a mid level oil)
4. Elite catch can as described and sold by COSPEED.
If I have left any pertinent info out please make additional comments. I look forward to more feedback on this thread.
08-16-2016, 05:55 PM
#48
I have noticed on decrease in power / performance yet but just the complete opposite. At about 6600 miles the performance has increased even with this bad weather I have been getting better 60', 1/8 & MPH compared to when the weather was cool and nice. I did install a catch can on my none Z51 @ around 2000 miles.
12-25-2018, 03:26 PM
#49
1st Gear
Backyard over “engineering”.
I have noticed on decrease in power / performance yet but just the complete opposite. At about 6600 miles the performance has increased even with this bad weather I have been getting better 60', 1/8 & MPH compared to when the weather was cool and nice. I did install a catch can on my none Z51 @ around 2000 miles.
A catch can is a great idea. So us using a spray in top cleaner every few thousand miles. Better yet a methanol injection system to prevent build up in the first place, as well as protect from detonation. With this said, disassembling your engine seems just crazy to me. The deposits that build up over several thousand miles will affect performance in a very negligible, or not at all way. This is an example of back yard mechanics second guessing real engineers with an overly invasive, time consuming procedure that may actually damage the engine. That’s my two cents as a mechanical engineer with 35 years experience. Sounds like changing your oil every 3000 miles. A waste of time, money and valuable resources. All that said, it’s nice to see fellow Americans that are actually thinking for a change, and all opinions are valued.
Last edited by Richard Hartman; 12-25-2018 at 03:39 PM. Reason: Addition
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Pineapple (12-25-2018)
12-25-2018, 03:36 PM
#50
A catch can is totally unnecessary on the LT1, and there is zero evidence that valve coking causes any performance degradation in LT engines well over 100K miles. Even if there were, there is no evidence that a catch can would prevent such a problem from occurring.
Last edited by Foosh; 12-25-2018 at 03:37 PM.
12-25-2018, 04:00 PM
#51
I don't know......The "related thread" is how to replace my pistons! It seems like a tough project for most of the non-mechanic owners to me. For somebody that can't do these projects himself this project would appear cost prohibitive when compared to just keeping Mobil 1 ESP 0-40W Dexos II oil, and running the engine as it was intended, which would be running it pretty hard, then paying a mechanic to "fix it up" whenever this carbon build up needs addressing as relates to engine performance. What would it cost me to have Cospeed product installed, and have a mechanic do this procedure every 10,000 miles? I am interested as I own a 2019 Stingray with 800 miles on it
12-25-2018, 05:47 PM
#52
Le Mans Master
I don't know......The "related thread" is how to replace my pistons! It seems like a tough project for most of the non-mechanic owners to me. For somebody that can't do these projects himself this project would appear cost prohibitive when compared to just keeping Mobil 1 ESP 0-40W Dexos II oil, and running the engine as it was intended, which would be running it pretty hard, then paying a mechanic to "fix it up" whenever this carbon build up needs addressing as relates to engine performance. What would it cost me to have Cospeed product installed, and have a mechanic do this procedure every 10,000 miles? I am interested as I own a 2019 Stingray with 800 miles on it
#2. That said, a catch can, properly installed, is pretty benign and shouldn't have any adverse effect on the engine, as long as you keep the can emptied
#3. I don't believe that running Dexos oil, or non-Dexos oil, will make any real difference in carbon buildup. That buildup comes from oil and bypass gasses that are fed into the intake system to be burned.
#4. Running the engine hard or easy probably has little to no bearing as well. The buildup is on the ambient side of the intake system, so the elevated cylinder pressure&temp that a hard run generates never sees the carbon buildup.
If I can ever get some time to pull the intake on my '14 (maybe spring break?) I'm going to see what's what. AFAIK it'll be one of very few LT1 engines that have been inspected for carbon buildup after 100k+ miles in stock condition and use.
HTH, and have a good one,
Mike
12-25-2018, 08:20 PM
#55
Race Director
Nope. I thought what you posted was legitimate.
My comment was for anyone who feels like making work for themselves. Maybe next time someone will produce some instructions on how to clean the inside of an exhaust manifold. In all fairness to the OP, I would sure like to know what symptoms he was attempting to address with this process.
My comment was for anyone who feels like making work for themselves. Maybe next time someone will produce some instructions on how to clean the inside of an exhaust manifold. In all fairness to the OP, I would sure like to know what symptoms he was attempting to address with this process.
Last edited by PatternDayTrader; 12-25-2018 at 08:35 PM.
12-25-2018, 09:42 PM
#56
Good thread. A couple of observations. 1) The engine being serviced with the intake valve cleaning has 13,000 miles with the catch can installed at 7000 miles. So 6000 miles with the catch can and 7000 miles without the catch can. With that said, the valve looks very dirty. Whether it is dirty enough to affect performance is a question. 2) If the engine intake valves are this dirty at 13,000 miles it appears the catch can is not as effective as thought. 3) I am really concerned now about the condition of the intake valves with higher mileage, say 100,000 miles. I have a 2016 Z51 I purchased new with no catch can. It has just over 14,000 miles on it now. I had sort of bought into Tadge Juechters position that the dry sump oil system has a built in blow by gas recirculation system that minimizes the amount of oil in the intake air that causes the valve coking. I just don't know now. I would like to see other engines at various mileages torn down for an intake valve inspection at say 20,000 miles, 40,000, 60,000, 80,000 and 100,000 miles with engine dyno testing to see if we have a problem compared to the amount of coking observed.
12-25-2018, 09:56 PM
#57
Le Mans Master
Have a good one,
Mike
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Catchcans (05-23-2019)
12-25-2018, 10:36 PM
#58
Race Director
Good thread. A couple of observations. 1) The engine being serviced with the intake valve cleaning has 13,000 miles with the catch can installed at 7000 miles. So 6000 miles with the catch can and 7000 miles without the catch can. With that said, the valve looks very dirty. Whether it is dirty enough to affect performance is a question. 2) If the engine intake valves are this dirty at 13,000 miles it appears the catch can is not as effective as thought. 3) I am really concerned now about the condition of the intake valves with higher mileage, say 100,000 miles. I have a 2016 Z51 I purchased new with no catch can. It has just over 14,000 miles on it now. I had sort of bought into Tadge Juechters position that the dry sump oil system has a built in blow by gas recirculation system that minimizes the amount of oil in the intake air that causes the valve coking. I just don't know now. I would like to see other engines at various mileages torn down for an intake valve inspection at say 20,000 miles, 40,000, 60,000, 80,000 and 100,000 miles with engine dyno testing to see if we have a problem compared to the amount of coking observed.
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ptalar (12-25-2018)
12-26-2018, 11:18 AM
#59
Race Director
12-26-2018, 11:24 AM
#60
Team Owner
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