I have a Honda marine engine BF225 that is a 3.5 ltr v6 that I think is a marinized version of the Odessey engine. I made the following post on a couple of boating forums but thought there may be more expertise here to help with my confusion.
I will appreciate any assistance.

I had the timing belts changed on my BF225 Honda's this week. I received a call from the shop Friday PM that there is a problem with one of the motors. I go to the shop this morning and they tell me that when starting the starboard engine after the belt change it was running rough. They pull the plugs and there is no compression on the right bank. When I arrived they were doing a leakdown test on the right bank. The numbers were high.

I am thinking they screwed up the timing. The tech assured me the timing was right. They pull the head and find one of the valves is bent, and no indication that the valves hit the piston(I couldn't see any). Now they are telling me that excessive carbon build up in the head caused this failure.

My motors have 1300 hours on them. The same shop(authorized) has done all of the scheduled maintenance. The plugs have been pulled every 100 hrs and the plugs have always been whitish and no indications of carbon buildup. The plugs were last pulled about 20 hours ago. I do not use Ringfree or any of the other similar products. The engine appeared to be running normally when used the last time about 3 weeks ago

The shop owner is telling me that the carbon buildup bent the valve an broke the valve guide. They want to replace the valve and do a shock treatment of ringfree. I am having a hard time believing this one. Can anyone enlighten me?

Thanks,
Aubrey

 

if the engine was running fine prior to having the timing belt replaced then i fail to see how it will bend a valve from "carbon" build up. i never heard of carbon build-up causing that issue before.

it sounds like the tech who was working on the engine initially put the belt on wrong OR the camshaft snap rotated while removing the old belt and the valve hit the piston.

i change V6 Toyota timing belts on a regular basis and sometimes while removing the old belt one of the camshafts will quickly snap rotate if you do not have the timing marks lined up perfectly. thankfully most of the Toyota V6 engines are non-interference but i do believe some of the Honda V6 is so that could very well be the issue.

 

Thanks for the info.

I went to the shop this morning to talk to the owner. He is still maintaining that it was a carbon buildup that caused the problem. I told him that I believed that the only way the valve could have bent is for the valve to contact the cylinder. He said that it did not because there was no evidence of the contact. Well after a little pissing contest and me getting a little hot under the collar, I told him that I wanted to speak to the Honda tech rep. I called the tech rep and the first question he asked was who gave me the number(A little adversarial from the beginning). The short story is that he didn't want to get involved between me and the dealer. I asked him what would bend a valve. He did say that the only way was for the valve to contact a cylinder. He also asked me why I was having the timing belt changed. I told him because the motors had 1300 hours on them and I thought it was time. He said that Honda never recommends a belt change unless there is indications of problems with the belt. I said that since it was an interference engine that I just wanted to use extra insurance of a good belt. He again stated that it is not necessary and that he has 1990 engines with thousands of hours that have never had a belt change.

One thing in my earlier post, I said that the valve guide had been broken. That was an error on my part. It was a spacer instead.

 

wow whats it to them if you want to change the timing belt or not? Its your motor you choose to do what you want.

 

Ask to see the piston and valve your self.
Was there any carbon built up on the valve or the piston that could lead them to believe that? If so, you should see the part where the impact occurred. Don't let them screw you if it was there fault.

 

carbon buildup would not bend a valve, especially enough for it to cause a large compression loss. i would take the "bent valve" to a machine shop and have it checked just to confirm for yourself it is infact bent. and if its bent i would ask the machine shop what they think of the carbon buildup excuse. you should be able to find all the answers your looking for

 

just how NAH2B said it. take it to a machine shop and get it checked out.

 

if it ran fine before the belt job then it was damaged in the process of getting the belt replaced. they could have pulled the belt off and spun the cams to tdc which hit the valve on the relief

 

I must agree with the rest of the member's info on this Aubrey. Many of these guys with the four digit post count have experience building engines, and not customers engines, so you know the info comes from tusted trial and error experience (including myself, I build alot of British engines). These chaps at your shop just want to get away scot-free from what was obviously a technician error. Now just because they have taken care of you before, it doesn't mean they are trying to take care of you this time. I work at a shop, and I'm telling you this from experience. Good luck and if you cannot speak any softer, make use of your big stick (no pun intended).

 

^^post count has nothing to do w/ experience

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NAH2B &raquo;</TD></TR><TR><TD CLASS="quote">^^post count has nothing to do w/ experience

</TD></TR></TABLE>I know that first hand. Thus, the subtle use of the word "many" and not "all".

 

Thanks again to all.

More bad news. I had a call fro the shop today. The head with the bent valve was sent to a machine shop. More valves were bent. I do not know whether it is intake or exhaust valves and it may be all. I'm working tomorrow so will deal with it next week.

BTW, the engines are 05's but I bought them in Dec '04 so it is not a warranty issue.

I do have another question if somone could help me. Is it possible that the engine could be running smoothly with no noticeable decrease in performance and the compression good on all cylinders with multiple bent valves?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aubrey &raquo;</TD></TR><TR><TD CLASS="quote">Thanks again to all.

More bad news. I had a call fro the shop today. The head with the bent valve was sent to a machine shop. More valves were bent. I do not know whether it is intake or exhaust valves and it may be all. I'm working tomorrow so will deal with it next week.

BTW, the engines are 05's but I bought them in Dec '04 so it is not a warranty issue.

I do have another question if somone could help me. Is it possible that the engine could be running smoothly with no noticeable decrease in performance and the compression good on all cylinders with multiple bent valves?

</TD></TR></TABLE>

no. it would show most of the time. im almost certain the damage was caused by poor installation of the new belt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by projectTeG &raquo;</TD></TR><TR><TD CLASS="quote">

no. it would show most of the time. im almost certain the damage was caused by poor installation of the new belt</TD></TR></TABLE>

absolutely.

 

Do i think carbon build up could cause a bent valve? - Not really.

If it was just one valve, i would MAYBE give them the benefit of the doubt.

But now that it is all of the valves, i would most certainly say it was timing error caused by the shop