Hello All,

First off, this thread is merely for discussion of the valve failure pictured below and I would like to keep it that way if at all possible. I welcome all relevant comments or questions. But anyways, I'll get down to business...

So a buddy of mine asked me to rebuild his 95' GSR engine this summer and I accepted as a good friend would do. When I asked him why he wanted a rebuild, I was told that he was "at WOT up a hill at 100 mph in 5th gear with 4 other people in the car...then I heard a BOOM". He told me that he was only running on three cylinders after that and his assumption was blown ring lands on #3. The engine itself had over 180,000 miles on it so I didn't even bother doing a compression or leakdown test since it was about time for a rebuild anyways. This saturday my other buddy and I began the tear down process...Once the head was pulled, this is what we found...

I'll leave it open for discussion at this point. My theory is that lugging the engine in the manner described caused some bad detonation and in turn a hot spot on the exhaust valve which led to high heat stress and ultimately fracture. Let me know what everyone thinks.

 

Interesting. On my 91 EX Accord (F22a4) with about 180K miles this happened on cylinder # 3 as well. I bought the car with 155K miles and did basic maintenance to bring it to par. It was my daily driver at the time and completely stock motor. I don't remember driving it hard and one day noticed it was running on 3 cylinders. Ended up building up another motor for it anyhow, since that is what I got the car for in the first place.

I never really know or found out why. Perhaps that cylinder fuel injector leaned out on me? The motor was stock and I replaced spark plugs soon after buying it, so I don't think it was that either. Someone mentioned to me that I may have ran too tight of valve lash on that valve, but I don't buy that. Yes, I had done valve lash somewhere between 155K and 180K, but I set them to stock .010" INT/.012" EXT. Even if I was .001 or .002" tight I doubt it would cause an issue. Oh, I did run that Lucas Seafoam through the intake system sometime before the damage as well, just wanted to give you all the information I had.

I'm interesting in knowing what you find out.

 

Good info on a similar but different situation...

Any other comments fellas???

 

TTT

 

That is not really a fracture. It is just a good old burnt valve from detonation/ not seating to remove heat from the valve surface. i would think the piston has some marks and broken ring lands also.

 

I mean no disrespect Don, as I know you are very experienced, but looking very closley at the valve you can see evidence of fracture (the picture does not do justice). Do you have any pictures of "burnt" valves for comparison? I don't doubt that detonation caused this, but isn't a burnt valve caused by an engine running lean for an extended period of time? I will see if I can remove the valve tonight or tomorrow and clean it up so I can take a better picture. I appreciate your responces everyone.

By the way, ring lands, pistons and cylinder walls were all in good shape...I would guess that this occurred during the exhaust stroke and the fragment got sucked out the exhaust port. Just a thought...

 

You are right, what was i thinking. That is definitly a clean break and not a burn mark.

 

Don't be so hard on yourself Don :-)

Keep the comments coming guys!

 

I always found the term "Burnt valve" funny because its freakin metal...you can't exactly light it on fire and burn it in the traditional sense.

DonF is correct though, old engine, the valve probably didnt seat properly on that one spot and heated up until it cracked. 180k fuel injectors probably didnt help and leaned it out just a bit (or a dirty fuel filter, etc), thus it was running leaner/hotter then a stock GSR should. Then the valve doesnt seal properly, coupled w/ your friend putting the engine at high load (and high heat output) for extended periods of time (4 people in the car, uphill and at a high rpm in 4th gear) and the heat trapped in the valve finally makes it snap. Then agian, looking at the CC, doesnt appear it was running all that lean. All the same, I have seen this twice before in engines I purchased and its always the same story.

 

no, it is a burn. don is right, he is being a smart *** and saying "what was i thinking" perhaps burn is a bad word and "melt" is a better word.

its a combo of the 2. that area melted/burned and got soft/thin and broke the rest of the way off. ive done this to 2 motors. 1 yota, 1 honda.

 

this happened to me back in 2000 on my 94 integra. i did a compression test and it was 180 on 1,2, 4 and 0 on 3. i took the head off and it looked exactly like that. i replaced the valve and lap the valve. it read 180 on all cyclinders and 100k later the car is still being driven by my mom without oil consumption.

http://autos.yahoo.com/maintain/repa...ques053_1.html

end/

 

blew up my first gsr this way too. the only difference was mine was caused by oil coating and not being able to cool on the seat.

 

BTW, on Hondas (and most 4 cylinders) it will almost always be cylinder #3 because of the TB placement and IM design...for the newbies of H-T.

 

DonF is most definitely right. That's what a burnt valve looks like, a "fracture". Had the same thing happen on my wrx. Cause happened to be built up carbon on the seats not letting the valve close completely and dissipate enough heat.

 

DonF is a dumbass. He's got no clue what a burnt valve is.

 

Hmmm...I guess I learned something new today. As I said before, I ment no disrespect to Don or anyone else for that matter. I'm always willing to learn more. I would agree that the phrase "burnt valve" is not exactly the best terminology because that definitley looks like a fracture. Just so we're clear, are most of you saying that it started out as a burnt valve and then was unable to cool sufficiently and fractured during the high load condition?

I just found this: "A "burned valve" is a valve that has overheated and lost its ability to hold a leak-free seal. Valve burning is usually limited to exhaust valves because they run much hotter than intake valves."

Doesn't mention anything about fracture but I could see how fracture would be a direct result of a burnt valve. Any more comments guys?

 

Could you explain this in more detail??? I'm curious as to why that is...

 

Where did you get pics of all those "fractured" valves?

 

Am I being made fun of Don?

 

Not "made fun of" so much as "mocked".

 

Better get use to it around here. You wouldnt be part of the family if someone didnt mock you every now and again.

On the #3 runs lean idea. Basically the TB/IM setup makes this happen. Air comes in from the TB on the far side of the engine (by cylinder #4) and can't make the sharp turn into cylinder #4. It also cant make it all the way down to cylinder #1 as its the furthest away and the other cylinders are trying to pull air in as well and get to it first. Thus, the way the IM/TB are designed leads to more air going into cylinders 2/3....specifically #3 due to the angle. All cylinders get the same amount of fuel (unless you have a fancy EMS). Thus, more air, same amt of fuel = leaner. Obviously not a huge problem as stock engines run for 200k+....but a problem all the same.

Yes, thats about as dumbed down as I can make it.

 

95 Integra - Thanks for your explanation. It makes a lot of sense and I'm sure all who didn't know that before understand it now. Nice work.

As far as the "mocking" goes, this thread was started for the purpose of discussion and for people to have the opportunity to learn (including myself). Those of you that feel it is necessary to poke fun at others that don't know as much as you, please keep those sorts of comments to yourselves. Nothing is accomplished when those comments are made and you're only making yourself look bad. Again, I mean no disrespect to any of my fellow honda-tech members. I am simply trying to have a civil discussion about a broken valve.

With that being said, I welcome any more valid comments regarding the original post.

 

Mockng was not the point, you wanted the opportunity to learn, WELL the correct answer was in post #5. But as you know more than that, or think you do, with NO research, you should get hamnmered. You asked a question, got the correct answer and did not understand it.
What other comments do you need, it is not a BROKEN valve. It is a melted/burnt valve. This is caused by heat. The valve seat removes the heat and transfers it to the head, then it transfered to the water/oil systems.

 

Nothing like thermodynamics.
OP, yes the valve was damaged due to being burnt. Get a new valve, valve job, and get the car running again. I can post a pic of a burnt valve I pulled from a recent rebuild if you're not convinced.

 

No one on this forum should "get hammered" for starting a legitimate discussion about a part failure. Had I posted a question somewhere along the lines of "How much horsepower will I gain from ... ???" then I would expect a certain amount of negative remarks. The fact is that, while your (DonF) posted answer in #5 is correct, it is still vague for those of us who have not seen this type of failure before. Not to mention that in the very same post you assumed there would be piston/cylinder damage, of which there was none. So what am I suppose to do? Just say "Thanks Don" and be on my merry way? The purpose of this post was to start a discussion. I did not simply ask "what happened to this valve?" Had that been the case, this thread would have been done 20 posts ago.

By the way, I used the word "broken" as it is defined here (http://dictionary.reference.com/browse/broken) on line number 4. So...whether the valve is burnt, melted, or fractured...it is in fact "broken".

This all being said, I would like to apologize to DonF and others for having to deal with my ignorance on this topic. I got the information I was looking and I thank those of you who contributed to the thread. Next time, I will be sure to do more research before posting. Have a nice day everyone.