Yanmar 4JH4-TE Catastrophic failure

[Hunterdog]

Originally Posted by Shaneesprit

Hi
Well from what I see
Broken bolt and spread big end, the big end of the rod failed first - possible a Torque issue on build but you have 1200 hours so unlikely to be torque.
I don’t believe a top end failure caused the big end to fail, because I have seen and investigated a lot of failures and never seen the top end failure damage the Rod at the crank - I have seen the Rod bent due to top end failure but not splay the big end.
Looks like over speed to me - Engine runaway from diesel in the oil from running at low RPMs for 1200 hours. Diesels like and need to be used hard it’s even in the manual. Low load running causes diesel to flow down the cold bores into the oil raising the oil level and causing a runaway and possible over speed!
Like the oil level in the boat manual.
So you were on the vessel,
1) did the engine go with a BANG or did it Scream and BANG?
2) when was the oil last changed? and I mean you know it was actually changed - not the last time you paid for it to be changed?
3) get an oil sample analysis- see if it’s new oil - unfortunately they can’t analyse the oil grade.
But don’t worry about mixing oils there is no issue with that as long as the oil is suitable, they just don’t want to mix due to having you on their oil and reputation - it’s a Turbo engine? if the oil was wrong Turbo always fails first

1. It wound up, high rpm...then I shut it down...waited a few minutes and restarted in neutral. Ran it up and down...then finally a klunk.
2. Oil change end of June, 2019. In that 8 month time, the boat was parked for about 2 months in the Med, It was right around the 250 hours to be changed again...But i check the oil often, and added small amounts a few times.
3. I have the oil, but not sure if I should do it here on the island...,

[Hunterdog]

Originally Posted by sealife2

Hi Hunterdog
i have experience with 4jh yanmars
the carboned up turbo is exactly what happens after approx 1000- 1500hrs... when run at lower rpm combined with no mechanical cleaning or every few hours hi rpm cleaning cycles as per yanmar maintenance/ operating instructions. it results in reduced power, reduced, rpm, little or no boost and excess carbon build up in the cylinder heads.
the one clean cylinder head section to me indicates a regular small amount of water being run through that cylinder... the water vaporizing when that cylinder fires removes the carbon over time its not a one gulp thing that cleans a cylinder head like that, as someone else mentioned.
given that one cylinder has most likely had water ingested regularly and the others are dirty it would seem the leak was into that one cylinder only... often a gasket leak or occasionally casting pin/ corrosion hole
it only takes a tiny bit of water to lock the cylinder. those motors can run with a bent rod bent/ rod cracked piston for a while . its possible that partial locking happened several times, it would be only a mater of time till something let go.
if someone had the head off and reused the old head gasket...leakage, is a common result.
the red stuff in the head cooling ports if rust likely means salt water in the coolant chambers fro a leak if it is RTV sealant someone already had the head off ...
the turbo flange connection discolouration also shows its had water sitting in there, most likely nothing new as it has crept under the gasket
the leaking mixer may have caused a problem but i think it is not likely the failure culprit as only one cylinder shows evidence of ongoing water ingestion.
perhaps your exhaust system isn't designed correctly but i would think that is not the main failure cause.
competent service would have caught the turbo and water issues much earlier in the cycle

BTW the new engines (common rail) require Very very clean fuel. For reasonable life make sure your filtering system is up to it.
Best of luck with the new install.

Sealife:
Please explain the ‘water’ that gets into the cylinder...where is it coming from?
The head was never off on this engine. It’s never been taken apart.
Thanks
Hunterdog

[Uncle Bob]

Originally Posted by kvstein

I have a fairly new 3JH-5e. The owner's manual specifically forbids motor sailing and says the transmission must be in neutral while sailing. I turned on the motor once when the boat was fully powered by sail. Big noise and I have never done it since.

Hi, I wonder if you could direct us to the section of the manual that specifically forbids motorsailing, I cannot seem to find it online.
Thanks in advance.

[Wotname]

Originally Posted by sealife2

Hi Hunterdog
i have experience with 4jh yammers............


the turbo flange connection discolouration also shows its had water sitting in there, most likely nothing new as it has crept under the gasket
the leaking mixer may have caused a problem but i think it is not likely the failure culprit as only one cylinder shows evidence of ongoing water ingestion.
perhaps your exhaust system isn't designed correctly but i would think that is not the main failure cause.
competent service would have caught the turbo and water issues much earlier in the cycle

BTW the new engines (common rail) require Very very clean fuel. For reasonable life make sure your filtering system is up to it.
Best of luck with the new install.

A belated welcome aboard CF, sealife2. A great first post (IMO) and one worth waiting for. I think you analysis makes a lot of sense.

[Hunterdog]

Originally Posted by Uncle Bob

Hi, I wonder if you could direct us to the section of the manual that specifically forbids motorsailing, I cannot seem to find it online.
Thanks in advance.

Here’s a link to the manual:
https://www.yanmarmarine.com/theme/yanmarportal/uploadedFiles/Marine/productDownloads/Leisure-Previous-Models/Operation-Manuals/JH4_OM_05JUNE08.pdf

Page 46, #2. (2008 edition)

Note: my boat, built 2011, but splashed in 2012, has the 2009 edition manual, and the notice is on page 50.

[skipperpete]

Originally Posted by Hunterdog

Wow. This engine was serviced by a yanmar dealer in oct 2018 and again in June 2019.

I was planning to service again this month before heading back to the Med. I had hoped to find a good shop in Gran Canaria as there are so many boats that pass thru for the arc.

To explain how the water gets into the turbo and cylinders here’s a photo of a similar mixer elbow that was still working on a 125 hp 4JH but had caused corrosion damage to the turbo and to the cylinder closest to the flywheel (7°inclined engine) but no other cylinders. Your engine has all the damage on the front two cylinders ( stuck exhaust valve on #3).
Does your dock and go act as the autopilot when you motor sail and is it possible that somehow it was involved? How much did the engine rev up, scary high rpm or just like ¾ to full throttle?
Thanks for the link to your blog,I enjoyed the video.

[DumnMad]

I think page 46 of the manual confirms my view than you slapped it out of gear at the critically wrong monment.

Originally Posted by DumnMad

Hunterdog, Have you ever surfed in the breakers at the beach ?
You (boat) don't slide down a wave, you get pushed by the forward motion of the water at the top of the wave. When you are just in front of the wave the water is dragging you back towards the breaker that is about to overtaking you.
Your motor revved up when the prop was just in front of the wave as the water dragged back and the prop had nothing to push, then you shut it down at the critical moment when the water direction reversed and shoved from behind. Almost like you went from forward gear to reverse.

[sealife2]

Originally Posted by Hunterdog

Sealife:
Please explain the ‘water’ that gets into the cylinder...where is it coming from?
The head was never off on this engine. It’s never been taken apart.
Thanks
Hunterdog

Hi Hunterdog
you ask Where is water coming from
to further inform comment / narrow the field of inquiry re leak
i would want to know the following

1-is engine inclined toward the cleaned cylinder or away /is the lowest -internal- part of turbo flange/manifold connection higher or lower than the clean cylinder with the boat at rest
2-Can you confirm the cleaned cylinder is farthest from turbo
3-the red material in the cooling ports of the head... is it rust or something else (it looks like sealant ) a closer photo would help
4- did you monitor the coolant ie did the level drop or rise in the overflow tank recently
5- is there salt water in the coolant (check overflow tank)
6- is there antifreeze/corrosion inhibitor in the coolant (check overflow tank)
7- Has the coolant been changed as per yanmar spec
8- is there any sign of discolouration or corrosion on the head gasket or mating surfaces of the block or head, particularly around the clean cylinder.
9-was the exhaust mixer leaking internally or just externally as it appears in the photo (it can be pressure tested to determine where it is leaking )

these questions/ answers only inform the ongoing water in the cylinder question

big end failure is a separate question maybe linked to water in cylinder maybe not

exhaust design is another question it may or may not cause water getting into the engine


a suggestion would be to repost close up or hi rez photos for the head ,turbo, block , big end bearing surface and crank journal its difficult for readers (me ) to find the photos or blow them up clearly

if you suspect the exhaust design is defective posting a series of photos of the complete system from turbo to hull exhaust port including anti siphon with elevations of each component above at rest loaded waterline would help others make informed comment

i assume what you are after is long term reliability with the new install.
to that end i would

confirm exhaust design is suitable
confirm your fuel filtering is suitable, what works for your 4 jh4-te isn't necessarily good enough for a common rail engine
regular oil sample testing for engine and gear from the same testing facility each time to establish a baseline for ongoing comparison ie Cat SOS mail in. really important to do the gear oil testing
regular coolant change to spec and or testing
establish a relationship with a reliable yanmar shop the can quickly supply and ship common rail , gear parts and trouble shooting information.

gosh that was long winded!!!
Cheers
J
fluid sampling how to link
https://www.cat.com/en_US/support/ma...ke-sample.html

[OneBoatman]

To Hunterdog You could have a couple of things contributing. As for the manufacturing Skipperpete is correct in stating that your conrod was likely forged rather than cast. Though you wouldn't know this by looking at it both appear comparatively unfinished compared to a machined finish. In as much this rod bent rather than breaking its metallurgy was probably as intended that being dense grained near the surface for strength and larger grained in the core for toughness. I have since looked at some of your pictures and I agree with your post stating that the connecting rod came off. It certainly would if one of big end cap bolts broke at the base of threads though hard to say from your pictures if ther is witness of a two stage break. Why its mate would be found loose in the pan is an even greater mystery. Could one have been over torqued and the other been too loose when assembled who knows. Is it likely, not very; is it possible, yes. The stress of a hydro lock would, if it occurred, very easily bend the rod and do a bunch of damage but I wouldn't expect to find a comparatively unscathed cap bolt lying free in the pan. How indeed would its lose its entire engagement into the rod journal and have but a ding on its head albeit the head is the hardest part. The corrosion on the turbo and the crack in your exhaust elbow I wouldn't think contributed.

[RaymondR]

If the broken bolt was an oilfield drill string component we would describe the failure as "first engaged thread failure". It is indicative of high cyclic stress causing a fatigue failure.

Since the other bolt appears fairly damage free my guess would be that the nut on the unbroken bolt loosened with the broken bolt taking on the full load of retaining the bearing cap until it finally fatigue failed under the very high stress levels it was experiencing.

The bearing shell then rotated with the crankshaft and acting as an unyielding packing under the in-place bearing shell caused the piston top to smash into the head and thereby initiating all the top end damage of the reciprocating components.

Ohh for castelated big end bearings and split pins.

[Hunterdog]

Thanks again to all of you. I’m learning a ton here about how an engine fails...and especially learning something about the marine engine market. Frankly, compared to what I was used to in LBS (life before sailing), I am quite surprised and amazed that these engines require so much TLC and are relatively fragile. Perhaps all new boats should come with some intense engine op training (similar to attaining ones pilot license) or
Just prior to setting off on this world sailing tour about 2 years ago, I had a construction and development business in California. Over a 30 year period I owned and operated many machines that used big and small engines.: A cat 12G grader, Deere 400 dozer, Case backhoe, Deere 310 Backhoe, Gradall 534D (three of them), Komatsu PC75 UU excavator, and a little Kobota with Gannon. The crew and I put many thousands of hours on all that machinery and I recall it mostly was very reliable...had a few issues, like one time climbing a loooong steep hill with one of the oldest Gradall, and one of the rod bearings failed. But is was an OLD engine, maybe 25 years. And we put those machines trough incredibly dirty and difficult conditions!

..I also owned and operated several aircraft. One of them was a Beech Baron, twin IO470 engines. One nite, flying over the mountains near Lake Tahoe desolation wilderness area, the left engine had a very similar rod failure as this boat engine. But, that engine was near it’s tbo, and even though I did oil analysis regularly, and the plane flew about 3 days a week...I actually was not too surprised that I encountered a catastrophic failure given that I had accumulated nearly 3000 flight hours by that time (engine was near 1600 at that time). Aircraft engines...every part is shaved to its absolute minimum for size and weight. The tolerances are just soooo thin. One almost expects something to go wrong. . And we monitor every cylinder temp and exhaust gas temp etc.
So to learn now all the different permutations of possible failure of a marine engine, my faith in the modern sailboat has fallen considerably. Especially this thing about the exhaust elbow. The part seems to have quite a short lifetime for such an important role it plays. Could they not just engineer it better?
Here’s a story another sailor sent me recently, as he’s watching me suffer through this: https://www.pbo.co.uk/expert-advice/...he-elbow-24029
Am I totally out of line here? Or does the boat engine market need to step things up and find a better way? It’s not like weight or space is an issue!
On the hard,
HDOG

[SaltyMetals]

hunterdog, i bought a Bene 25 yrs ago, did thousands of hrs on the Yanmar 48 but never had a prblm. Still going v well today at about 4-5,000 hrs. I sold my half to my friend and now hv a 2004 Jeanneau 75hp turbo, about 2,000 hrs on the engine. Never any prblms, just oil & filter changes at the due time. I think you just had some bad luck. It surprises me that sea water could have come back up the exhaust but while i have often done it myself the marine engine guys do not recommend running the engine while sailing in heavy seas. I find it useful since it throws some water against the rudder and helps the steering but i would only be running at 1500-2000 rpm. I think the primary risk is that the oil in the sump runs across to one side in the rough seas and the oil pump gets starved. Anyway i never found it a prblm but try and avoid doing it too often.

In all the photos you have posted none of them show a close up of the fracture surface of the broken bolt. This will show if there was already a previous crack progressing before a catastrophic failure. As to why there might hv been a crack progressing previously is open to speculation. Manufacturing defect? Too much torque? imbalance of the torque levels between the bolt on one side and the other? Or water from the manifold, which, by the photo , looks to have another two cracks on it.

Best of luck in your claim but send me a close-up of the fracture surface of the broken bolt if you can.
Andrew
(Yes, for my sins, i studied metallurgy many moons ago....)

[Shaneesprit]

This was a bottom end failure of the big end bolt, there are only 2 causes of this.
1) over speed - ok overspend has its own cause list. all of them requiring fuel.
2) Big End Bolt Failure.
dispelling a few myths here.
Water ingestion bends the Rod nearer the seeker Small end among other damage, but this would not damage the big end bolt that snapped, as the load on the rod is to the crank not away from it.
The big end has failed, the failure of this is caused by the mass of the piston reaching the top of the cylinder, Rod Big End spread is either material failure of the bolt holding the rod together or over speed.
The bolt really hasn’t just come loose, if it was even half a turn loose and certainly at one full turn loose failure would be immediate. Via engine knocking you would hear it with a loud heavy knock

[RaymondR]

Originally Posted by Shaneesprit

This was a bottom end failure of the big end bolt, there are only 2 causes of this.
1) over speed - ok overspend has its own cause list. all of them requiring fuel.
2) Big End Bolt Failure.
dispelling a few myths here.
Water ingestion bends the Rod nearer the seeker Small end among other damage, but this would not damage the big end bolt that snapped, as the load on the rod is to the crank not away from it.
The big end has failed, the failure of this is caused by the mass of the piston reaching the top of the cylinder, Rod Big End spread is either material failure of the bolt holding the rod together or over speed.
The bolt really hasn’t just come loose, if it was even half a turn loose and certainly at one full turn loose failure would be immediate. Via engine knocking you would hear it with a loud heavy knock

If one bolt comes loose the remaining bolt is going to retain the bearing cap in place until it either loosens or fails. Be mindful that these and the head bolts are usually the items on an engine where torquing the bolt to a significant percentage of the yield of the bolt is required for long and reliable operation. The bolts are also generally high tensile.

Piston velocity can be related to the sine of the crank angle and consequently the reversal of direction is relatively smooth and stress excursion free.

In these circumstances the engine may continue to run without any indications of an incipient problem for some time before failure.

The defining factors in this engine failure are:

One undamaged bolt indicating loosening of it's nut. The proximal cause of the
failure.

And.

One bolt which failed at the first engaged thread. A consequent cause of the nut
loosening.

The first failed in it's function because it lost it's nut and the second most probably fatigue failed after being over stressed for some number of excessive-stress cycles.

[RaymondR]

Originally Posted by RaymondR

If one bolt comes loose the remaining bolt is going to retain the bearing cap in place until it either loosens or fails. Be mindful that these and the head bolts are usually the items on an engine where torquing the bolt to a significant percentage of the yield of the bolt is required for long and reliable operation. The bolts are also generally high tensile.

Piston velocity can be related to the sine of the crank angle and consequently the reversal of direction is relatively smooth and stress excursion free.

In these circumstances the engine may continue to run without any indications of an incipient problem for some time before failure.

The defining factors in this engine failure are:

One undamaged bolt indicating loosening of it's nut. The proximal cause of the
failure.

And.

One bolt which failed at the first engaged thread. A consequent cause of the nut
loosening.

The first failed in it's function because it lost it's nut and the second most probably fatigue failed after being over stressed for some number of excessive-stress cycles.

Hunterdog,

In light of the above, and if the engine has not been disassembled and reassembled in way of the bottom end by someone else I believe you have a claim against Yanmar for incorrect assembly leading to catastrophic failure.

You need to bring this to their, and I say their not their just agents or distributors, attention. They are a reputable manufacturer and would most probably offer some compensation or replacement of the engines damaged components. At 1,600 hours the engine has only expended a minor fraction of it's design life.