Yanmar 4JH4-TE Catastrophic failure

[Wotname]

Originally Posted by Hunterdog

NO
NO
NO
NO...I’ve only owned it for 18 months...
Now...this is the big one...cause I’ve rever really heard it. AND 99% of the time I’m running at 1400 to 1800 rpm.
I’m in no hurry, and don’t like wasting fuel!!
I run it up to 2600 rpm, just for 30 seconds once in a while just to see what top speeds are given how clean the bottom is etc...

The following is given as a friendly suggestion - not a criticism!

The recent engine failure would have been mostly been prevented if you (or the previous owner) had maintained the engine in accordance with the Yanmar operations manual. Yanmar requires the turbo to be cleaned every 250 hours (or every year) and as Skipperpete points out, it is easy to inspect at lesser periodic intervals. I am sure whatever caused the turbo (and valves) to be corroded is also the same thing that caused the recent catastrophic failure. This would have been discovered if the servicing had been done correctly.

I can understand why you want to operate between 1400 and 1800 for 99% of the time but please follow the instructions in the 4JH4-TE operations manual. Running at 2600 for 30 seconds occasionally isn't sufficient to keep the internals free of carbon etc. Max rpm for this engine is 3200!

From the manual -

7. When operating the engine at low speed for long periods of time, race the engine once every 2 hours.
Note: Racing the engine: With the gear in NEUTRAL, accelerate from the low speed position to the high speed position and repeat this process about 5 times. This is done to clean out carbon from the cylinders and the fuel injection valve. Neglecting to race the engine will result in poor exhaust color and reduce engine performance.
8. If possible, periodically operate the engine at near maximum rpm, while underway.
This will generate higher exhaust temperatures, which will help clean out hard carbon deposits, maintaining engine performance and prolonging the life of the engine.

Anyway, that is history now, you have a brand new 4JH80 that you can operate exactly as Yanmar suggests. If you have not already done so, I encourage you to read and follow their new engine break-in procedures (first 10 and first 50 hours).

[a64pilot]

I would suspect that without boost max RPM was 2600, and I’m surprised it turned up that high with no boost.
Is this a Common rail motor? Some of them have boost sensors and won’t feed fuel if the air isn’t there, they won’t smoke like a train like a mechanical injection motor will if the turbo isn’t working.
My Duramax even had a mass air flow sensor like a gas motor.

[rslifkin]

There have even been some mechanical injection setups that were boost-referenced (to reduce acceleration smoke), but I don't know how common they ever were on boat engines. With a boost-referenced setup, you wouldn't get excessive smoke from a low boost situation (although you might get a little more smoke than normal), you'd just experience low power.

[Hunterdog]

Didn’t smoke at all...

[Hunterdog]

Originally Posted by Wotname

WAG

Perhaps the OP has only operated the engine at low rpm (???)

At some point, everyday, there is a reason for lots of power:
Last month pulling in and out is essouira, Morroco with winds and swell...
A few weeks before in and out of Gibraltar and crossing the straits.
On December 25 I even charted speed vs power from 1200 to 2800 rpm.
(Being a heavy equipment operator and a multi engine pilot...I’m nerdy this way).
That says 7.7, BTW. I just use the writing tool with my fat fingers...sorry...
Then, on Jan 30, I ran the same experiment after a bottom job. Gained 3/4 knot.
So, that would indicate a normal engine??

[Wotname]

Originally Posted by Hunterdog

.........
(Being a heavy equipment operator and a multi engine pilot...I’m nerdy this way).
............

Then I apologise for suggesting you read the manual regarding the break-in period upthread.

Still, it may be of benefit to some other reader who stumbles across this thread

[Wotname]

Originally Posted by Hunterdog

At some point, everyday, there is a reason for lots of power:......
That says 7.7, BTW. I just use the writing tool with my fat fingers...sorry...
Then, on Jan 30, I ran the same experiment after a bottom job. Gained 3/4 knot.
So, that would indicate a normal engine??

Not really.
I understand however even 2800 is no where near max power for the 4JH4-TE which occurs 3200. Look at the fuel figures - ~10.5 l/hr at 28000 and ~17l/hr at 3200. Max power is going to be at max fuel burn.

Reaching hull speed is no test for engine health.

A red flag would be not reaching near max rpm at WOT assuming clean bottom (and prop), calm water and correctly sized prop. Hull speed under these conditions should be reached well max rpm for your hull / engine size, probably below 2400. Heavy smoke at WOT and low rpm would a dead give away.

[Wotname]

Originally Posted by a64pilot

I would suspect that without boost max RPM was 2600, and I’m surprised it turned up that high with no boost.
Is this a Common rail motor? ...

No, the 4JH4-TE is a not a common rail engine.
The OP's new engine 4JH80 is a common rail (but not turbo).

[Hunterdog]

Thanks wotname. That was actually very cool if you. Inappropriate all the efforts of everyone on this thread. The entire world iof experiences can now be shared. It’s amazing and awesome. I just share my experience because being ‘aware’ of mechanical things is a piece of the puzzle, I believe.

But after all this, I am very suspect of the yanmar shop that did all the maintenance since 2012.

The mechanic here says it was just ‘bad luck’ that this set of circumstances occurred:: marginal engine with a rogue over speed due to the sea state.

But I don’t believe it: I think some inspection items were overlooked....
Hopefully they will be forthcoming. Thanks for all the help.
H

[Hunterdog]

Originally Posted by Hunterdog

Thanks wotname. That was actually very cool if you. Inappropriate all the efforts of everyone on this thread. The entire world iof experiences can now be shared. It’s amazing and awesome. I just share my experience because being ‘aware’ of mechanical things is a piece of the puzzle, I believe.

But after all this, I am very suspect of the yanmar shop that did all the maintenance since 2012.

The mechanic here says it was just ‘bad luck’ that this set of circumstances occurred:: marginal engine with a rogue over speed due to the sea state.

But I don’t believe it: I think some inspection items were overlooked....
Hopefully they will be forthcoming. Thanks for all the help.
H

Errata:
‘I appreciate’

H

[Wotname]

Originally Posted by Hunterdog

Maybe not: it was corroded stiff:
Mechanic says valves too corroded too.

But why the breakage right then? Is it just chance?
And I have receipts of full service just 8 months ago...
Should this be an inspection item?

Originally Posted by Hunterdog

..... I have the broken parts. Maybe I should open an investigation?

I can't help thinking there has been a sad chain of errors.

At some time the turbo has frozen up but when?
What was the root cause of the turbo problem?
How many hours at the last service?
How many hours since the last service?

Did the OP sell you a dud?
If so, why wasn't it discovered before now?

If the turbo problem has occurred after the sale, why didn't it become obvious until too late?

Of course I don't know the answers but a careful analysis of known history of the engine should point towards the root cause.

[Hunterdog]

Originally Posted by Wotname

Not really.
I understand however even 2800 is no where near max power for the 4JH4-TE which occurs 3200. Look at the fuel figures - ~10.5 l/hr at 28000 and ~17l/hr at 3200. Max power is going to be at max fuel burn.

Reaching hull speed is no test for engine health.

A red flag would be not reaching near max rpm at WOT assuming clean bottom (and prop), calm water and correctly sized prop. Hull speed under these conditions should be reached well max rpm for your hull / engine size, probably below 2400. Heavy smoke at WOT and low rpm would a dead give away.

I ran it up, but the speed barely moved...so I left the data off.
Was more interested in developing the curve for efficiency sake.

[Wotname]

Originally Posted by Hunterdog

.........

But after all this, I am very suspect of the yanmar shop that did all the maintenance since 2012.

The mechanic here says it was just ‘bad luck’ that this set of circumstances occurred:: marginal engine with a rogue over speed due to the sea state.

But I don’t believe it: I think some inspection items were overlooked....
Hopefully they will be forthcoming. Thanks for all the help.
H

Sounds like that to me also.
I wonder how he is going to pin the dodgy turbo on the sea state!!!!

[Wotname]

Originally Posted by Hunterdog

I ran it up, but the speed barely moved...so I left the data off.
Was more interested in developing the curve for efficiency sake.

OK,that is to be expected. This suggests the turbo was OK at that time.

[SaltyMetals]

As I said earlier you need to take a really good look at th fracture surface of the item that broke first. Try not to scuff the surface when you extract the parts. A metallurgist can tell you if it will show a progressive fracture that had been happening for many wks/mths beforehand or whether it was an instantaneous fracture. It is not rocket science for a metallurgist. V simple. This would solve the doubt as to whether it was sea water backing up in yr exhaust or a manufacturing defect in th engine.
Andrew
(Yes I did a degree in metallurgy for my sins)