Carbon Buildup 101

[Night Fury]

Let's talk about this topic, all feedback area welcome! ​

So what is it? It is a buildup of carbon material on the top of your intake valves (between).

Causes: In my head, a bad design ( pretty much all new engine models), and the absence of an extra injector to clean all that crap inside the engine.

A more elaborated answer, copied from another forum:

To understand what causes carbon buildup, you first need to understand how our engines work. At its most basic, an engine burns two things: oxygen and fuel. In our case that fuel can either be gasoline or diesel. So, an appropriate mixture of fuel and oxygen are needed in the combustion chamber to explode when the spark plug ignites. In the old days, oxygen and fuel were mixed in the carburetor and passed to the engine over the intake valve. In more recent times, a fuel injector sprayed a fine mist of fuel into the intake port. From there the air/fuel mixture passed over the intake valve into the combustion chamber. This was called port injection (you still see this advertised on older GM cars). Port injection was a huge leap forward in terms of both power and fuel economy. You could much more finely control the mixture, and dynamically control the mixture based on what the various sensors were communicating to the ECU.

I'm thinking already on:

• Catch can. Link
• Nut shell blaster valve cleaning Link
• Oli flush ??
• Eventually sea foam Link

Thoughts?

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[JLOracing]

the main thing that causes carbon buildup to be so bad on later cars vs previous is direct injection. With Port Injection the oil vapors would mix with the fuel before passing over the intake valves and this would help prevent the oil in the vapor from sticking to the valves. Now with direct injection, the inject sprays fuel directly into the combustion chamber and the oil vapor passes over the hot valves only with oxygen, and much of it will stick to the valves and over time the build up can get very bad, i have seen it first hand, and cleaned it on many VW. This is where a catch can comes in, it catches the oil, and separates it from the air before it can reach the valves, greatly decreasing carbon buildup

 

[Night Fury]

Another area where I have seen oil is in the intercooler hoses.

 

[Kevin S.]

from what i can tell this is not a problem with honda. I can't find out why though? I know toyota uses port injection and direct injection to solve the problem. What is honda doing ? I've heard rumors they are using a different pcv setup - built internal of the cyl head ? There is lots of info i'm finding online but my google fu is failing me. I can't find the exact answer lol

However i will say that my aunts 2016 accord 2.4 has been flawless and is close to 60k. My 13 accord sport didn't have any issues within 20k i put on her. The earth dreams direct injected motors seem to not have any issues related to this. i can't find anything from any of the forums for the fk2 guys in the uk either...

No tsb's or recalls are available that i have seen either.

I'm guessing it is not an issue!

 

[PolishedLX]

from what i can tell this is not a problem with honda. I can't find out why though? I know toyota uses port injection and direct injection to solve the problem. What is honda doing ? I've heard rumors they are using a different pcv setup - built internal of the cyl head ? There is lots of info i'm finding online but my google fu is failing me. I can't find the exact answer lol

However i will say that my aunts 2016 accord 2.4 has been flawless and is close to 60k. My 13 accord sport didn't have any issues within 20k i put on her. The earth dreams direct injected motors seem to not have any issues related to this. i can't find anything from any of the forums for the fk2 guys in the uk either...

No tsb's or recalls are available that i have seen either.

I'm guessing it is not an issue!

good post from Kevin from Denver everyone. what a swell guy.

 

[baldheadracing]

The PCV system is on the pressurized side of the intake system, so oil-laden mist cannot affect the turbo or intercooler in the Type R engine. There is also an air/oil separator built into the engine to reduce oil entering the (pressurized) intake manifold via the PCV system. You can still put a catch can on the PCV system, but the need should not as great as it would be in a motor that vented to the intake system before the turbo or before the intercooler.

YMMV. I do have a catch can, but I haven't installed it yet.

 

[JLOracing]

I have a oil catch can setup as well, on the PCV side, just to be safe and just another way to monitor engine performance. I made it out of a universal Mishimoto 2-Port can. After 40 minutes worth of track time, there wasnt much oil in the can, but this was only 40 minutes......

 

[davidgostbo]

Let's talk about this topic, all feedback area welcome! ​

So what is it? It is a buildup of carbon material on the top of your intake valves (between).

Causes: In my head, a bad design ( pretty much all new engine models), and the absence of an extra injector to clean all that crap inside the engine.

A more elaborated answer, copied from another forum:

To understand what causes carbon buildup, you first need to understand how our engines work. At its most basic, an engine burns two things: oxygen and fuel. In our case that fuel can either be gasoline or diesel. So, an appropriate mixture of fuel and oxygen are needed in the combustion chamber to explode when the spark plug ignites. In the old days, oxygen and fuel were mixed in the carburetor and passed to the engine over the intake valve. In more recent times, a fuel injector sprayed a fine mist of fuel into the intake port. From there the air/fuel mixture passed over the intake valve into the combustion chamber. This was called port injection (you still see this advertised on older GM cars). Port injection was a huge leap forward in terms of both power and fuel economy. You could much more finely control the mixture, and dynamically control the mixture based on what the various sensors were communicating to the ECU.

I'm thinking already on:

• Catch can. Link
• Nut shell blaster valve cleaning Link
• Oli flush ??
• Eventually sea foam Link

Thoughts?

Do not, I repeat do not use sea foam on direct injection engines! Says specifically so in owners manual

 

[Night Fury]

Do not, I repeat do not use sea foam on direct injection engines! Says specifically so in owners manual

Copy

 

[NoelPR]

from what i can tell this is not a problem with honda. I can't find out why though? I know toyota uses port injection and direct injection to solve the problem. What is honda doing ? I've heard rumors they are using a different pcv setup - built internal of the cyl head ? There is lots of info i'm finding online but my google fu is failing me. I can't find the exact answer lol

However i will say that my aunts 2016 accord 2.4 has been flawless and is close to 60k. My 13 accord sport didn't have any issues within 20k i put on her. The earth dreams direct injected motors seem to not have any issues related to this. i can't find anything from any of the forums for the fk2 guys in the uk either...

No tsb's or recalls are available that i have seen either.

I'm guessing it is not an issue!

Share the same thought. Never heard about of a later Honda DI engine with carbon build up problem. Pretty there are but are very rare.

 

[Almostfast]

I guess it's good to read nobody has found any serious evidence of valve gumming. I've owned two DI engines, a Ford and a Subaru. The Ford has every overheating problem under the sun and the Subaru looks like it was running Maple syrup through the intake.

On the Subaru they blame the EGR (exhaust gunk regurgitation) for most of the caking. Hopefully the Honda is designed a lot better, I couldn't stand to own three issue prone vehicles in a row...

 

[shihabp79]

Use high quality premium fuel with detergents in it that will help reduce carbon buildup immensely. People that have these problems on modern DI engines are usually filling up at Costco, Valero, grocery stores, etc., or putting in lower octane gas to save a buck.

 

[TheBigG]

Use high quality premium fuel with detergents in it that will help reduce carbon buildup immensely. People that have these problems on modern DI engines are usually filling up at Costco, Valero, grocery stores, etc., or putting in lower octane gas to save a buck.

It has nothing to do with the fuel.
The fuel doesn't touch the intake valves to clean them. This is the problem in DI engines.

 

[fk8mike]

watermeth injection and catch can

 

[shihabp79]

It has nothing to do with the fuel.
The fuel doesn't touch the intake valves to clean them. This is the problem in DI engines.

DI may not spray the back of intake valves but Top Tier gasoline has other additives that help keep deposits from “sticking” to your valves. Combined with an oil catch can to prevent fuel/oil vapor from being recirculated, it’s your best bet to reduce carbon buildup.

So how do Top Tier fuels like Chevron and Texaco with Techron, Shell’s Nitrogen-Enriched, and BP’s Invigorate work? Each employs top-secret organic chemistry (Chevron admits theirs involves a polyether amine. Others often employ polybutene amines, if that helps), but by and large the molecules include a “hydrocarbon tail” (that keeps the detergent soluble in fuel) attached to a head that includes a functional group containing nitrogen. When enough of these nitrogens attach to a deposit, it comes off. Then the nitrogens can attach to the clean surface and prevent new deposits from forming. The fresh challenge with DI is designing functional heads that don’t lose their cool at temperatures of 4000 degrees F or higher.

Chevron and Shell both claim that running a few tanks of fuel can remove the deposits left by miles of use of minimum-standard fuels.

http://www.motortrend.com/news/all-fuels-are-not-created-equal-technologue/

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