Honda 225 broken valve: catastrophic failure

Michael Marris · Mar 4, 2010

My 2003 225 with 170 hours had the #6 cylinder problem (water entering through exhaust). It has been in the Honda shop the past three months (over the NZ summer) whilst we negotiated repairs. They did a full service, and handed it back to me last week. Five hours on, at about 4000rpm and in good conditions it went BANG. Literally, BANG. And stopped.
Back to the shop: inlet valve on #3 cylinder disintegrated (see pix). This is the opposite side to the one that had been worked on. This head had not been removed. Problem is to find cause. Shop did decompression and leakdown tests before releasing it to me: all good. Therefore (they say) not a bent valve. One theory is the valve seal came free.
I would appreciate any thoughts, speculations or deep knowledge. I have some other pix & can answer questions. Big question in my mind is why this happened just 5 hours after a major overhaul. Seems to me the two events should somehow be related. Thanks for your input.

comanr · Mar 5, 2010

Re: Honda 225 broken valve: catastrophic failure

i suggest it could be foreign material left by mistake in the intake manifold.the thing helped the exhaust valve to stay a little open and the piston bang...one theory... you said the engine had the other head down few days before the show...

by the way if everything is ok except the head, this one can be done ok by making a new seat (you need a handy guy) ,and a new valve(or 2 valves)

bye.
coman r.

Michael Marris · Mar 6, 2010

Re: Honda 225 broken valve: catastrophic failure

Thanks for the foreign material ingested idea. It was also raised with me by an aircraft engineer. It would make a coherent explanation. (But, of course, how to determine????)

There are also thoughts of a valve seat failing or a valve head/stem fusion failing - both however would be unrelated to the other recent work done on the engine.

I will take it to a head shop on Monday to see if there is other means of identifying the causes.

To me the timing seems important and I cannot easily believe that the two events (exhaust modification work on port side and catastrophic vale disintegration on stbd side) are not somehow linked, given the 5 hours or less of running..

Again, ideas and speculations, as wild as you care, are most appreciated. I am searching for answers and the $20,000NZ repair quote (= about $US 14,000) is not a pretty thought. Honda NZ are running for the hills at present, but I sense at some point they will have some liability in all of this. First, I need some sold facts, and usually before fascts there come specualtions and ideas: your are most welcome.

Thank you.

comanr · Mar 6, 2010

Re: Honda 225 broken valve: catastrophic failure

when the "sucking water in" issue is happening ,it may break a seat (exaust one) since there is the hotest spot of the chamber ,due to instant cooling of the seat. so maybe the water in issue struck again.

it is very difficult to determine the exact phenomenom , i think the second theory makes the first...it seems the engine did not stop imediately since the marks on the piston cannot be made in 1 revolution of the crankshaft. if you were a little bit lucky the seat could escape (in pieces) directly in the exhaust leaving the valve not broken,then 100% sure, water damage to the seat. in the picture the seat is gone as i can see or i am wrong?

if this is how i saw it, it may be a wrong head design or exhaust design or manufacturing of the head was deffective.

try to see if there are other people sharing the same water issue.

BaileysBoat · Mar 6, 2010

Re: Honda 225 broken valve: catastrophic failure

Is this the only head damaged? If you have other bent valves I would suspect the timing belt wasn't adjusted correctly and jumped. However, usually you only bend the valves.

What exactly did the "full service entail" Were both heads removed?

In that case a valve retainer failure/only one of two installed on the valve would be my guess.

Engine ran for 5 hours at speed, so unlikely foreign object?
Can't tell from the picture but is the valve seat still installed?

Good pics.

Michael Marris · Mar 6, 2010

Re: Honda 225 broken valve: catastrophic failure

Thanks to you both Comanr and BB. I am most appreciative.

The valve seat has gone.

The full service followed a repair modification to the exhaust following water ingestion in #6. That head was seized. Only the port head was removed (apparently on instructions from Honda NZ).

Other valves on this startboard head are bent. However, I was told any timing issues would have been revealed on the decompression and leakdown tests that were performed before the boat was handed back to me.

Any further thoughts are greatfully received.

Michael

comanr · Mar 6, 2010

Re: Honda 225 broken valve: catastrophic failure

inspect all other seats from exaust valves.if you have cracked seats,wich you may have, you have a case, and you can do something about .

have a nice day.

Silvertip · Mar 7, 2010

Re: Honda 225 broken valve: catastrophic failure

If there are other bent valves, this is a classic case of valve/piston interference due to bad cam timing. Bad cam timing results from improper isntallation or slipping of the timing belt or chain on an overhead cam engine. Interfence engines are called such since if a timing belt or chain breaks, pistons WILL collide with any open valves. Non-interference engines (of which there are fewer these days) can have a belt or chain break without having interference. I don't feel the original problem and this problem are related other than by the fact that the engine was worked on. Since the head has already been removed, there is no way to prove if the belt/chain had been installed properly.

comanr · Mar 7, 2010

Re: Honda 225 broken valve: catastrophic failure

ok. bent valves and broken valves but what about cracked seats,missing seats,something is not ok here.the seats are usually very solid since they are not aluminium.let s see if there are cracks in other seats then the theory with the timming belt slippage is not so true...

Silvertip · Mar 7, 2010

Re: Honda 225 broken valve: catastrophic failure

Valve seats are an interference fit in the head. Hardened steel set in aluminum. A slipped or misadjusted timing belt causes piston/valve interference. The head bends, so it now strikes the seat at an angle cracking it. It no longer is an interference fit, falls out of the cavity and dances around on the end of the valve. if a valve head snaps, it dances around in the cylinder striking everything which can also loosen seats. At 5000 rpm loose parts become pieces of loose parts. Some go out the exhaust and some stay inside. Since we have damaged valves and damaged seats in other cylinders, an interference issue is even more confirmed. Hydrolock cannot occur except when the valves in any cylinder are closed. When closed, you likely will not do valve damage but you can do piston and rod damage.

Silvertip · Mar 7, 2010

Re: Honda 225 broken valve: catastrophic failure

Another thought on this is an overly lean fuel mixture. In I/O engines a lean mixture at high rpm can tulip a valve. While that results in a compression loss, on a pushrod engine it does not generally result in piston/valve contact. If that happens in an interference engine, the end result can be catastrophic.

Michael Marris · Mar 8, 2010

Re: Honda 225 broken valve: catastrophic failure

UPDATE: thank you all for a remarkable and insightful range of possibilities. I am very grateful, and your comments have significantly helped my thinking (and that of local experts here in NZ). I have posted this on two boards, and the willingness of you all to so readilycontribute your expertise has taken me by surprise.

Today I took the head and valves to a specialist engineering shop.
The fellow (Wayne) had already told me he would also want his partner to look at the head. However, Wayne did say, quite quickly after close inspection, that he had a clear theory. He would not say until after his partner has also seen it. That will be next week when he returns from leave.

So this is an interim report from me. When I hear their views in about a week's time, I will report back.

Meanwhile, thanks a bunch.

Michael

Silvertip · Mar 9, 2010

Re: Honda 225 broken valve: catastrophic failure

Please do keep us informed -- we don't often hear back from folks as to whether their issues ever were resolved. Yours is a very interesting case and I in particular would like to know what the outcome is.

BaileysBoat · Mar 9, 2010

Re: Honda 225 broken valve: catastrophic failure

As above, very interested.

comanr · Mar 9, 2010

Re: Honda 225 broken valve: catastrophic failure

we hope ,whatever will be that you will hear your engine again.we tryed here to help you from few diffrent kinds of view based on long experience and work.
sometimes in life , the things just depend on luck no matter what we do.so luck spending little money on this engine be with you.

good luck!

tommays · Mar 9, 2010

Re: Honda 225 broken valve: catastrophic failure

http://www.youtube.com/watch?v=5G5pV_N4QbM

I had to change a head gasket on this good running A4

While i was there i pulled the valves to change the springs and one exhaust valve fell apart

kind of good the gasket started leaking

comanr · Mar 9, 2010

Re: Honda 225 broken valve: catastrophic failure

do you suspect timming belt slippage?

4stroked · Mar 13, 2010

Re: Honda 225 broken valve: catastrophic failure

Have Had 2 of these occur before.

Both were heavy boats under heavy loaded conditions. In both cases the exhaust valve on # 6 cylinder failed. IMO the valve stuck in the guide and then contacted the piston eventually breaking the valve head off and imbedding it in the cylinder head. Both engines had well over 2000hrs on them.

Honda has upgraded the valves in these engines and this has not occured in any of the updated models.

comanr · Mar 14, 2010

Re: Honda 225 broken valve: catastrophic failure

it seems like a warranty issue as i suspected, deffective manufacturing.maybe this is covered by warranty.
good luck!

Honda 225 broken valve: catastrophic failure

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