Intake valve build up - Pics Inside

kennerz · December 9, 2019

Build up like that effects low lift. Probably happens gradually enough that you would not notice the 1 or 2 mpg and 10 to 20 hp. Looks like enough to impact performance to me. I would get it walnut blasted at this point. When I pull mine after running a can with about the same mileage we can compare.

Grumpy Bear · December 9, 2019

This (above) is not that. (below) Carburetor motors look worse than this in a few thousand miles and will run a million or more taken care of like: https://www.growingbolder.com/romancing-the-road-259598/

THIS is what is being talked about when performance nose dives. Not the above.

This isn't what is happening in a Ecotec3.

Inacanyon · December 10, 2019

Makes me wonder how many port fuel injected heads you’ve seen. That looks barely worse than a similar mile ls1. Head looks great

Lsgun1 · December 10, 2019

You should be the guinea pig for the seafoam spray treatment to clean that. Do it and take an after shot. On Truck Tech they showed an before and after on a similar mileage truck and it looked good but the episode was sponsored by seafoam so who knows.

truckguy82 · December 10, 2019

Damn aluminum heads, oven cleaner would turn that into liquid carbon in like 10 minutes.

kennerz · April 3, 2021

Back from the dead, I performed a walnut blast intake valve cleaning recently, will upload pics of the before on a few of the valves. This is a serious problem. The only reason they don't absolutely run horrible is cause the intake runners in the heads are huge and the valve lift from the cam is huge too. There was soo much of this disgusting carbon like thick jelly and dirt/oil everywhere killed the low lift air flow over the valves. I immediately picked up 1.5~2 mpg and power increase/return is almost dramatic. Truck is a rocket again. Like the frog in boiling water analogy it (DI carbon buildup) is so gradual that you don't notice how bad it is.

I don't care what anyone says, it is a problem on these motors once you get up in miles and I'm sure significant buildup occurs well before you notice it. With post details on another new thread, how to, what I used, Was able to get them way cleaner with the walnuts over any other method. Was kinda a pain overall though. At least a half-days work taking your time.

If your truck has over 50k mi I would say it needs it. Mine was at 87k and was shocking to me and this was running an elite catch can, so who know how much that may have slowed it down.

mookdoc6 · April 5, 2021

On 4/3/2021 at 1:14 AM, kennerz said:

Back from the dead, I performed a walnut blast intake valve cleaning recently, will upload pics of the before on a few of the valves. This is a serious problem. The only reason they don't absolutely run horrible is cause the intake runners in the heads are huge and the valve lift from the cam is huge too. There was soo much of this disgusting carbon like thick jelly and dirt/oil everywhere killed the low lift air flow over the valves. I immediately picked up 1.5~2 mpg and power increase/return is almost dramatic. Truck is a rocket again. Like the frog in boiling water analogy it (DI carbon buildup) is so gradual that you don't notice how bad it is.

I don't care what anyone says, it is a problem on these motors once you get up in miles and I'm sure significant buildup occurs well before you notice it. With post details on another new thread, how to, what I used, Was able to get them way cleaner with the walnuts over any other method. Was kinda a pain overall though. At least a half-days work taking your time.

If your truck has over 50k mi I would say it needs it. Mine was at 87k and was shocking to me and this was running an elite catch can, so who know how much that may have slowed it down.

Very Astute DUDEMAN! There is many on this forum unaware/ignorant etc. misinformed etc. Your 100% correct on that Cam! I already told everybody it was aggressive and the intake runners yup HUGE! All done on purpose from GM Engineers to obfuscate the obvious and they usually accomplish their goal as GM has some of the best engineers without question! I will preach it again! I don't care if your 3k-5k-10k guy you have to keep these buggers clean and it's more work no doubt but the LT'S are awesome engines imo.....

Edited April 5, 2021 by mookdoc6

Grumpy Bear · April 5, 2021

So if build up in ALL GDI motors results in a loss of both power AND economy somebody explain to me why Pepper at 134,000 miles it still gaining in lifetime fuel efficiency and getting better numbers now than it did at 50,000 miles? This I gotta hear.

:lurk:

CamGTP · April 5, 2021

Here were mine at 104,000 miles, now I'm at 110,000.

Notice zero power loss, weird idle problems, still pulls 21+ mpg on the freeway easy. Not saying that the build up is fine but to lump all engines into that is a bit much. I know plenty of fleets running these trucks with high mileage doing okay still.

Edited April 5, 2021 by CamGTP

Grumpy Bear · April 5, 2021

6 minutes ago, CamGTP said:

Here were mine at 104,000 miles, now I'm at 110,000.

Notice zero power loss, weird idle problems, still pulls 21+ mpg on the freeway easy. Not saying that the build up is fine but to lump all engines into that is a bit much. I know plenty of fleets running these trucks with high mileage doing okay still.

Scoop! There it is!!!

I have a serious dislike for "Blanket Statements" and "F.U.D". Thank you Cameron.

truckguy82 · April 5, 2021

On 4/3/2021 at 4:14 AM, kennerz said:

Back from the dead, I performed a walnut blast intake valve cleaning recently, will upload pics of the before on a few of the valves. This is a serious problem. The only reason they don't absolutely run horrible is cause the intake runners in the heads are huge and the valve lift from the cam is huge too. There was soo much of this disgusting carbon like thick jelly and dirt/oil everywhere killed the low lift air flow over the valves. I immediately picked up 1.5~2 mpg and power increase/return is almost dramatic. Truck is a rocket again. Like the frog in boiling water analogy it (DI carbon buildup) is so gradual that you don't notice how bad it is.

I don't care what anyone says, it is a problem on these motors once you get up in miles and I'm sure significant buildup occurs well before you notice it. With post details on another new thread, how to, what I used, Was able to get them way cleaner with the walnuts over any other method. Was kinda a pain overall though. At least a half-days work taking your time.

If your truck has over 50k mi I would say it needs it. Mine was at 87k and was shocking to me and this was running an elite catch can, so who know how much that may have slowed it down.

Where are the pics?

also odd that you running a catch can have build up problems and everybody that doesn’t run one, who has posted pictures on high mileage engines, has no problems. Weird

Edited April 5, 2021 by truckguy82

diyer2 · April 5, 2021

A simple answer to this issue IMO.

If you are going to keep your truck for an extended time this is what I would do.

Catch can. Why not?

Shorter oil and filter changes than the computers OLM. Maybe consider 100% synthetic oil, Amsoil or?

Top Tier gas.

Grumpy Bear · April 5, 2021

GDI has been used since 1925. Mercedes in the 1950's used it and had these issues with it. Gave it a bad reputation. People like to hang on the what it was instead of what it is. What if we did that with rings and oil? We would still by shying away from motors over 60,000 miles and changing oil every other weekend.

How would a motor that uses no measurable oil over 5K miles benefit from a can. If it uses oil because of rings or valve seals how would a motor benefit from a can?

When someone says I picked up 1.5 to 2 mpg instantly???? Wishful thinking. You haven't collected data long enough to make a valid statistical argument for that.

truckguy82 · April 5, 2021

19 minutes ago, Grumpy Bear said:

GDI has been used since 1925. Mercedes in the 1950's used it and had these issues with it. Gave it a bad reputation. People like to hang on the what it was instead of what it is. What if we did that with rings and oil? We would still by shying away from motors over 60,000 miles and changing oil every other weekend.

How would a motor that uses no measurable oil over 5K miles benefit from a can. If it uses oil because of rings or valve seals how would a motor benefit from a can?

When someone says I picked up 1.5 to 2 mpg instantly???? Wishful thinking. You haven't collected data long enough to make a valid statistical argument for that.

I’m burning a boatload of oil. Don’t know where its going. If I don’t check it and add it, I’ll get a low oil level warning when the oil life monitor says I’m about 25% oil life remaining. That’s a lot of burning oil.

Owner of blackbear street tuned my truck, I told him about the oil consumption, and he said well it’s not the rings. Somehow he could tell that by looking at the live data.

i too get great mpg at 60k miles, seems good as new, and I take a ton of short trips, which is probably terrible for carbon buildup.

i would say I’m only running my engine for more than 20 minutes a time, once a month.

infact I’m gonna make a thread about it

Edited April 5, 2021 by truckguy82

Grumpy Bear · April 5, 2021

4 hours ago, truckguy82 said:

I’m burning a boatload of oil. Don’t know where its going. If I don’t check it and add it, I’ll get a low oil level warning when the oil life monitor says I’m about 25% oil life remaining. That’s a lot of burning oil.

Owner of blackbear street tuned my truck, I told him about the oil consumption, and he said well it’s not the rings. Somehow he could tell that by looking at the live data.

i too get great mpg at 60k miles, seems good as new, and I take a ton of short trips, which is probably terrible for carbon buildup.

i would say I’m only running my engine for more than 20 minutes a time, once a month.

infact I’m gonna make a thread about it

There's only four ways out, right? Leak, valve seals, rings or PCV system.

A can only helps the last.

Looking forward to your thread

So...I wonder...has anyone noticed these motors no longer have an EGR pump nor passages? Yet they do in fact utilize EGR. But instead of pumping exhaust into the intake they back fill the exhaust into the intake with a combination of cam events and injector timing. In the days of carburetors we called it 'reversion'.

:crackup: