Questions for the K20C1 engine experts here.

[Zone47]

1. There isn't proof out there about a trend of carbon build up problems in Honda DI engines.

2. The easiest way to avoid problems with a warranty claim is to not install aftermarket parts like a catch can. If that worries you, don't bother during the warranty period.

3. 1st engine change?
Here is your answer from a valid source.


4. 250K miles on these engine?
There isn't enough data out there to know that yet.
The K20C engine came out on FK2 CTR (europe), not enough years in the road to know their longterm reliability but so far the engine seems to be pretty good.

250K isn't a stretch at all IMO.... unless the car is tracked quite often.

I owned an Acura RSX typeS with the K20 family of engines and sold it at 216K just because after 14 years I was ready for something else. That engine ran amazingly well and have no doubt that it go another 84K or more. It started running it's best at around 100K miles. I remember thinking 'well, it is finally fully broken in'. I didn't run it that hard or flog it every chance I got as most of the time I was just going to work and back, but in general, Japanese engines, especially Honda and Toyotas are good for at least 300K or more. Yeah, I know we're talking a turbo engine now that will probably get flogged to death and this is more about general usage.

So to wrap it up; my buddy in CA has a 02 Toyota Tacoma with the 2.7L engine and he is at 730,000 miles. Yeah, he had to have a valve job, transmission rebuilt, ball joints but the point is, the truck still has the factory short block untouched! Pretty amazing if you ask me.

Your car if raced every weekend results may vary.

Sponsored

 

[TypeRD]

@Zone47 Both of those engines you referenced are port injected and are fantastically reliable. I’ve owned both or VERY close variants there-of : 8th gen Si (for almost 14 years) and a ‘98 (iirc) Tacoma with the 2.7L and 5 spd manual. Both were rock solid and trouble free. However, the OP is concerned with two things that make the K20C1 different than both of those older designs : 1. Direct Injection which has history of gunked valves…which can lead to reduced engine life. 2. Turbo…which if done wrong can also reduce engine life.

Basically @VLJ is looking for assurance that the engine will last 20 years with proper maintenance. To @optronix point, no one here has the answer to this as the K20C1 hasn’t been around long enough. Honda has had DI engines (including 2.0L) in production for the last 10-15 years now. Beyond that, no one would have any in-depth knowledge of the K20C1’s failure modes outside of Honda. There aren’t widespread reports of the 2.0L DI engine having gunked valves. I don’t think anyone knows exactly why that is, except Honda.

Anyway…we’re not talking about Chevy 350’s here. Buying any car with a newer engine design takes a bit of a leap of faith. If one can’t stomach this, it’s probably best to buy a clean, older, car with an entirely proven power train. It doesn’t hurt to try and dig for info and share experiences however. That’s what forums are for. But if you’re looking for THE answers to in-depth engineering questions, no one here can provide this and it’s not a worthwhile exercise to continue digging beyond a certain point…which I think the OP is finding.

 

[VLJ]

For questions like this, yes. Might as well shut it all down. Burn it to purge the evil lies too.

Seriously this whole conversation is about hearsay. I'm not sure why there's an expectation that some imaginary "experts" exist that somehow know the science of this specific engine better than Honda engineers, literally on a molecular level, and can give you the "real deal" better than what's in the actual owner's manual?

Just has a whole lizard people vibe to me, sorry.

It's not that difficult. Nothing vague, imaginary, or hearsay about what I'm asking; namely, is there any basic engineering in this motor that differs from other DI motors which helps prevent carbon buildup? If there is, then someone with extensive knowledge of this engine's specifics, of which there are many on this site, would simply answer, "Yes, Honda has added this design or component to this motor, which does this, while eliminating that...."

No different from the engineering-based explanation for why DI motors create carbon buildup on the intake valves in the first place, i.e., they're missing the port injectors that spray cleansing gasoline onto the tops of those valves. With DI only, you're missing that component, which allows carbon deposits to accumulate.

If Honda has introduced a solution and implemented it in their recent DI motors, I would expect there to be all sorts of press releases on the subject. Toyota's D-4S system and its ability to prevent carbon buildup is frequently mentioned in car reviews, and many videos have been made on the subject. I would expect something similar regarding Honda's solution, if in fact they have one for these motors.

 

[qingcong]

@Zone47 Both of those engines you referenced are port injected and are fantastically reliable. I’ve owned both or VERY close variants there-of : 8th gen Si (for almost 14 years) and a ‘98 (iirc) Tacoma with the 2.7L and 5 spd manual. Both were rock solid and trouble free. However, the OP is concerned with two things that make the K20C1 different than both of those older designs : 1. Direct Injection which has history of gunked valves…which can lead to reduced engine life. 2. Turbo…which if done wrong can also reduce engine life.

Basically @VLJ is looking for assurance that the engine will last 20 years with proper maintenance. To @optronix point, no one here has the answer to this as the K20C1 hasn’t been around long enough. Honda has had DI engines (including 2.0L) in production for the last 10-15 years now. Beyond that, no one would have any in-depth knowledge of the K20C1’s failure modes outside of Honda. There aren’t widespread reports of the 2.0L DI engine having gunked valves. I don’t think anyone knows exactly why that is, except Honda.

Anyway…we’re not talking about Chevy 350’s here. Buying any car with a newer engine design takes a bit of a leap of faith. If one can’t stomach this, it’s probably best to buy a clean, older, car with an entirely proven power train. It doesn’t hurt to try and dig for info and share experiences however. That’s what forums are for. But if you’re looking for THE answers to in-depth engineering questions, no one here can provide this and it’s not a worthwhile exercise to continue digging beyond a certain point…which I think the OP is finding.

To be fair, I don't think these are totally outrageous questions and should be perfectly reasonable things that a consumer ought to know about their product - 1) does the DI cause valve gunk and 2) is there any validity to keeping the factory oil till MM says to change it. I've been wanting to know about these myself. Unfortunately I think our society only cares about the latest and greatest, so these fancy turbo DIs just keep bragging about fuel economy and torque and we eat it up. A Honda engine engineer should put these questions to rest, but there is not enough demand for these questions. It's just us nerds who care.

 

[optronix]

It's not that difficult.

Indeed. How's that working out for you, in this sea of experts?

edit- before I "burn another bridge" with yet another forum member that hates me, I'm just saying that your questions are fair, but your expectations are probably not. I just don't think that the type of person who actually knows the answers to questions like these, well- exists. And if they do, they probably wouldn't post much here, as they probably have at least some deep connection to Honda whether directly as an employee or indirectly as an esteemed tuner... and there's possibly intellectual property at stake. Not so much for the valve gunk concern, but my point is they probably wouldn't deign to mingle amongst us mere peasant-class enthusiasts very often to comprehensively answer questions like these just to give us peace of mind.

I would actually love to be proven wrong as I find this shit fascinating, as does probably everyone else posting in this thread.

 

[VLJ]

If there were a hard-parts solution to this issue, I would expect someone to have come across specific info detailing the changes Honda made to the engine to prevent carbon buildup. All someone would need to do is provide a link to the press release from Honda, or to a review that mentions it. A channel like Engineering Explained would surely cover the topic.

Also, with all the aftermarket tuning and modifying of this motor that has been going on since Day One, I would expect that someone somewhere must have taken a look at the valves, and someone would have filmed and posted the results.

Basic stuff, in the internet age. That's how information gets disseminated these days. No black magic required, or word of mouth, or hearsay, or any of that. Forums like these are the wellsprings of such info.

 

[optronix]

If there were a hard-parts solution to this issue, I would expect someone to have come across specific info detailing the changes Honda made to the engine to prevent carbon buildup. All someone would need to do is provide a link to the press release from Honda, or to a review that mentions it. A channel like Engineering Explained would surely cover the topic.

Also, with all the aftermarket tuning and modifying of this motor that has been going on since Day One, I would expect that someone somewhere must have taken a look at the valves, and someone would have filmed and posted the results.

Basic stuff, in the internet age. That's how information gets disseminated these days. No black magic required, or word of mouth, or hearsay, or any of that. Forums like these are the wellsprings of such info.

Fair enough I suppose, but possibly there just isn't enough sample size with these motors reaching the level of usage/mileage to where they'll start exhibiting this behavior. Maybe ping the guy from EE to see if he'll do the legwork on the research for this topic. He's covered a shitload of CTR/ITS content already, maybe you'll get a bite.

And honestly if you haven't looked at the press kit for the Type R, if what you're looking for exists in the public domain, it will probably be captured there. I'm not really a press release kind of guy but they went to excruciating detail. The ITS too, but for that one there was kind of a focus on the delta between the R and the S.

https://hondanews.com/en-US/honda-a...d0f70179fdc-2023-honda-civic-type-r-press-kit

Valvetrain specifically:

Cylinder Head and i-VTEC® Valvetrain
The direct-injected, 4-cylinder turbocharged VTEC Turbo engine in the Civic Type R has a lightweight pressure-cast aluminum alloy double overhead cam (DOHC) cylinder head. With exhaust ports cast directly into the cylinder head, the need for a traditional separate exhaust manifold is eliminated, reducing engine weight and simplifying the assembly. The manifold is liquid cooled to help keep heat in check, reduce emissions, increase fuel efficiency and power.

A low-friction, silent chain drives dual overhead cams and four valves per cylinder. The cam drive is maintenance free for the life of the engine. To further reduce weight, thin-wall hollow camshafts are used.

To benefit fuel efficiency, emissions and power, the exhaust valves are sodium-filled for enhanced cooling. Since the valve is internally cooled, it doesn't need the enriched fuel mixture that is generally used in turbo engines to help cool exhaust valves. The resultant leaner mixture reduces emissions, increases fuel efficiency and increases power.

The DOHC 16-valve Civic Type R engine uses an advanced valve control system to combine high power output with high fuel efficiency and low emissions. Known as
i-VTEC®, the system combines intake and exhaust VTC (Variable Valve Timing Control), which continuously adjusts the intake and exhaust camshaft phase with Variable Valve Timing and Lift Electronic Control (VTEC) for the exhaust valves which changes their lift, timing and opening duration.

The “i” (for intelligent) portion of the system is its ability to continuously vary the timing of the intake and exhaust camshafts using variable valve timing control (VTC). This helps increase power and also provides a smoother idle (allowing idle speed to be reduced). The cam timing is varied based on input from sensors that monitor rpm, timing, throttle opening, cam position and exhaust air-fuel ratio, resulting in increased fuel efficiency and lower emissions.

The cylinder head includes small M12 sparkplugs, down from the more common M14, primarily to improve combustion chamber cooling. The head also includes direct-injection multi-hole fuel injectors with a small-diameter bore. Higher-pressure direct injection optimizes fuel atomization, allowing for more efficient combustion. To provide a high-tumble intake charge that further enhances combustion efficiency, both the intake port and piston crown have special designs.

 

[VLJ]

I'll check it out. Thanks.

Edit...

Nope, no mention in that massive tech release about any DI/carbon buildup mitigation. Only possible thing could be their description of the new, smaller sparkplugs and injectors creating super-fine atomization of the fuel within the combustion chamber, which could theoretically lead to less harmful waste escaping via blow-by.

Lot of press releases make similar claims, however, so really nothing new there.

Otherwise, that thing sure makes for an impressive read, doesn't it? Makes it seem like we've bought a Gordon Murray-designed F1 car for the street!

 

[vbb]

i installed a PCV Radium catch can shortly after purchasing my car. i periodically check the dip stick and there's definitely a small amount of oil in there.

 

[PointByPatrol]

I've borescoped all of my cylinders at 6500 miles. The cylinder walls looked great, but there is definitely carbon buildup on the intake valves.

 

[VLJ]

I've borescoped all of my cylinders at 6500 miles. The cylinder walls looked great, but there is definitely carbon buildup on the intake valves.

Is there enough to concern you?

Earlier in this thread someone posted a shot of severely gunked up valves at 38,000 miles on an FK8 motor, which is essentially the same as the FL5 design. It looked pretty bad.

It seems clear that Honda's DI motors are just as prone to carbon buildup as most other DI motors are, and with eight gazillion CR-V's, Civics, and Accords all running DI engines for many years now there should be plenty of data out there detailing what effects, if any, carbon gunking has on those engines. Perhaps the answer is that, yes, Honda's DI motors suffer from gunking just as other DI motors do, but it doesn't matter. It's not hurting anything. Whereas a lot of previous-gen VWs eventually suffered from cold starting issues, reduced fuel mileage, and reduced performance as a result of carbon buildup on the intake valves, somehow that same carbon bulildup has no negative effect on the Hondas.

This doesn't seem very plausible, but what else is there? Maybe it really is just that simple.

 

[Zone47]

Is there enough to concern you?

Earlier in this thread someone posted a shot of severely gunked up valves at 38,000 miles on an FK8 motor, which is essentially the same as the FL5 design. It looked pretty bad.

It seems clear that Honda's DI motors are just as prone to carbon buildup as most other DI motors are, and with eight gazillion CR-V's, Civics, and Accords all running DI engines for many years now there should be plenty of data out there detailing what effects, if any, carbon gunking has on those engines. Perhaps the answer is that, yes, Honda's DI motors suffer from gunking just as other DI motors do, but it doesn't matter. It's not hurting anything. Whereas a lot of previous-gen VWs eventually suffered from cold starting issues, reduced fuel mileage, and reduced performance as a result of carbon buildup on the intake valves, somehow that same carbon bulildup has no negative effect on the Hondas.

This doesn't seem very plausible, but what else is there? Maybe it really is just that simple.

My primary idea of buying a Honda was I wouldn't have to screw with pulling the intake and injectors like you do on the Vdubs but I guess I didn't research that well enough.

 

[qingcong]

Is there enough to concern you?

Earlier in this thread someone posted a shot of severely gunked up valves at 38,000 miles on an FK8 motor, which is essentially the same as the FL5 design. It looked pretty bad.

It seems clear that Honda's DI motors are just as prone to carbon buildup as most other DI motors are, and with eight gazillion CR-V's, Civics, and Accords all running DI engines for many years now there should be plenty of data out there detailing what effects, if any, carbon gunking has on those engines. Perhaps the answer is that, yes, Honda's DI motors suffer from gunking just as other DI motors do, but it doesn't matter. It's not hurting anything. Whereas a lot of previous-gen VWs eventually suffered from cold starting issues, reduced fuel mileage, and reduced performance as a result of carbon buildup on the intake valves, somehow that same carbon bulildup has no negative effect on the Hondas.

This doesn't seem very plausible, but what else is there? Maybe it really is just that simple.

I mean, I had all these questions unanswered when I bought my FL5 and at the end of the day it really came down to - if DI carbon buildup was going to deter me from getting a car, then I might as well get a boring Toyota/Lexus or keep my 9th gen Civic Si or go electric or something. There's not many great alternatives these days.

 

[VLJ]

I'm right there with you. Before I pulled the trigger on this FL5, I researched every option that was within shouting distance of the Type R. The only alternatives I found that aren't DI only are the GR86/BRZ, which use Toyota's D-4S port/DI system, but have other engine issues on top of the recommendation for 93 octane, which we don't get in California; the Lexus IS 350 F Sport and RC 350, which use Toyota's venerable NA V6 with D-4S, easily representing the most bombroof, longterm reliable option currently on offer by anybody; the Mustang GT, which isn't known for being all that reliable, but at least is free of DI only and turbos. 14 MPG, however, was simply a bridge too far for me.

In the end, I rationalized my way into the FL5 on the basis that it's a very special Honda, and Honda wouldn't allow their flagship motor to be compromised by something as easily preventable as carbon buildup on the intake valves.

I suppose I'm still leaning on that same rationalization, despite learning there's nothing unique about the motor that might prevent carbon gunking. I was hoping for more, but now I'm resigned to it.

As they say, it is what it is.

Sponsored