Valve Seal Issue on older Yanmar 6lp Engines

[chiefrcd]

I was searching back in the forums and only saw one post that even remotely discussed this problem with older Yanmar 6lp engines. Just wanted to bring up a reminder for those with early model Yanmar 6lps, if you have not had the newer seals put in your engine, you really need to discuss this with your local Yanmar Service Center. These engines will drop a valve and ruin the engine. Sometimes you can detect a problem when you decelerate rapidly. Sounds like you are rattling cans in the engine....sometimes there is no warning. There are a number of post over a boatdiesel.com and the yanmarhelp.com site. Just FYI....

[Elizabeth Ann]

Supposedly Mac Boring, the Yanmar distributor in the North East, can identify if you have a problem by the engine serial number.

[mhanna]

I am looking at at 28TE that has a Yanmar and called Mac Boring with the Serial #. They told me that this particular engine did not, according to their records have the seals replaced.
I will of course contact Yanmar to see what can be done and have seen some some positive comments from others.
I would like this done BEFORE any sign of the ticking, ect... would they do it in a proactive way or do they require the 'sign' that something is going bad first ?
But if they cannot do anything, has anyone paid for this to be done and if anyone could advise on how much it would be ?
Anyone have experiences with this ?

Thanks
Matt

[chiefrcd]

Hi Matt,
I did have it done. As far as your question regarding the " sign " that something is wrong. From what I gather...not always is there a sign. Some people just drop a valve and destroy their engines ( about $26000.00 to replace, less labor.) I have a engine with the old valve seals and I was having the loud clacking sound when I powered down from high rpms.... and this is what I did.

I contacted Mack Boring and discussed the repairs with them via e mail. I then talked with my local Yanmar Service Center, Deltaville Boat Yard who then contacted Mack Boring regarding any assistance they might offer. Mack Boring/Yanmar agreed to pay for, I think 4.5 hours of labor and all the parts to repair the valve seal issue. Deltaville Boat Yard then did the repairs for approx $965.00 of which I paid $35.00. I had the seals changed while the head was on the engine, which is much cheaper than removing the head. The repairs were completed and my engine ran like it was new. When I contacted Mack Boring regarding the repairs, my engine was 6 years old and had 600 hours on it. I was the second owner of the boat. The work was done a little over a year ago and I've had no problems or issues regarding the valve guides.

[Capt Paul]

Interesting that you should bring this up. I just spoke with my local dealer this week about this. I supplied my serial number and she told me that they could not identify this buy serial number. She contacted Boatswain Locker in the LA area and said this is what they told her. Being and engineer and knowing how things are tracked, I cannot believe this is the case. I sent an e-mail to Yanmar this morning and I'm waiting to see what they come back with. She did tell me that you can tell buy the color of the valve seals whether they are old or new. I believe the older ones with the problem are grey and the new ones are orange. Or something like that. I left my notes at work... Anyway, I may try and give Mac Boring a call and see if they can help me out.

Thanks,
Paul

[chiefrcd]

There are several long long threads back to 2004 on Boatdiesel.com if you're a member, you can't see them that far back if you're not. But in essence there seems to be some controversity as to if you can tell by the serial number or not. Based on what I've read, engines as late as 2002 can NOT have the newer seals. Also, say you have a 2001 boat, your engine manufacture date could be 1999 or 2000. One post even says he was told he had the newer seals and then his engine dropped a valve and they found out he had the older seals. Hopefully Mack Boring can help you, they've been very helpful for me the several times I've had dealings with them. I talked with a Mr. Tom Watts in the New Jersey office. I've also dealt with a Larry Berlin who use to post on boatdiesel.com often.

[Russell]

The information that I got on another site about this is that models 6LP-STE and 6LP-ST2E starting in 1996 have this problem. The exhaust valves have a brown stem and make a tapping sound during deceleration before going out. From Feb. 1 2002 and seriel number M51201 on, the valves were changed to the new design and have green stripes. The model number was changed to 6LP(A)-ST. So you can tell by the color of the valve stem if the conversion has been made on the older models.