Yanmar BY Series Upgrades

[one_more_drift]

Hi all,

I'm researching the upgrades for the Yanmar BY1 to BY2 Engine. Amongst the improvements; 1.) Plans were made to replace the dry exhaust manifiold to a new water-cooled manifold and 2.) To implement a new design flywheel with improved inertia.

I note that for a limited period, Yanmar replaced the dry exhaust manifold (as well other items) for customers who already had the older BY1 engines installed in their vessels. On top of this, Yanmar even reinstated the warranty period.

To me, this seems EXCEPTIONAL service from Yanmar.

But my questions, to those in the know please:

1. Why was it so important to replace the old dry exhaust manifold with the new coolant cooled manifold?
2. What make/type was the old flywheel.
3. Why was the flywheel improved; what was wrong with the existing flywheel?

I understand that this is for an older engine, but I'd be most appreciative for your answers.

Cheers

 

[Latestarter1]

Hi all,

I'm researching the upgrades for the Yanmar BY1 to BY2 Engine. Amongst the improvements; 1.) Plans were made to replace the dry exhaust manifiold to a new water-cooled manifold and 2.) To implement a new design flywheel with improved inertia.

I note that for a limited period, Yanmar replaced the dry exhaust manifold (as well other items) for customers who already had the older BY1 engines installed in their vessels. On top of this, Yanmar even reinstated the warranty period.

To me, this seems EXCEPTIONAL service from Yanmar.

But my questions, to those in the know please:

1. Why was it so important to replace the old dry exhaust manifold with the new coolant cooled manifold?
2. What make/type was the old flywheel.
3. Why was the flywheel improved; what was wrong with the existing flywheel?

I understand that this is for an older engine, but I'd be most appreciative for your answers.

Cheers

In reply to your questions.

Upgrades were not planned, they were mandatory at least in the U.S.

In answer to your question:-

Dry manifold simply failed, in certain duty cycle applications failure rate was 100% popping off exhaust studs. Dry exhaust manifolds on ANY make of diesel engine do not work, experience over the years, yet some couch engineers prefer to ignore collective experience. They appear to be seduced by the thermal gains alone. Recent Hyundai marine engine has fallen into exactly the same trap.

Original flywheel was simply the BMW flywheel fitted to automotive engines which employed a dual mass flywheel. In marine applications the lack of flywheel mass could cause all manner of torsional issues with transmissions ranging from rattles to total failure. Replacement flywheel was designed as marine flywheel with greater mass. There was also a software revision which allowed among other benefits idle speed to be adjusted which eliminated gearbox clatter.

There were a number of other marinisation components revised in the upgrade as well as those mentioned, not to mention a separate wiring loom campaign as a result of engine fires.

This was not a matter of Yanmar giving EXCEPTIONAL service, they had suffered a bruising experience at the hands of the U.S. legal system as a result of the 6LP valve drop Class Action and discovered that a more pro-active approach would save a heap of $$.

Most surveyors I speak to are aware of the campaign and any engine that was not captured is potentially a poison pill, as Yanmar parts prices are not just high, they are outrageous.

 

[one_more_drift]

In reply to your questions.

Upgrades were not planned, they were mandatory at least in the U.S.

In answer to your question:-

Dry manifold simply failed, in certain duty cycle applications failure rate was 100% popping off exhaust studs. Dry exhaust manifolds on ANY make of diesel engine do not work, experience over the years, yet some couch engineers prefer to ignore collective experience. They appear to be seduced by the thermal gains alone. Recent Hyundai marine engine has fallen into exactly the same trap.

Original flywheel was simply the BMW flywheel fitted to automotive engines which employed a dual mass flywheel. In marine applications the lack of flywheel mass could cause all manner of torsional issues with transmissions ranging from rattles to total failure. Replacement flywheel was designed as marine flywheel with greater mass. There was also a software revision which allowed among other benefits idle speed to be adjusted which eliminated gearbox clatter.

There were a number of other marinisation components revised in the upgrade as well as those mentioned, not to mention a separate wiring loom campaign as a result of engine fires.

This was not a matter of Yanmar giving EXCEPTIONAL service, they had suffered a bruising experience at the hands of the U.S. legal system as a result of the 6LP valve drop Class Action and discovered that a more pro-active approach would save a heap of $$.

Most surveyors I speak to are aware of the campaign and any engine that was not captured is potentially a poison pill, as Yanmar parts prices are not just high, they are outrageous.

Thank you LateStarter1 for taking the time to reply.. I was unaware of the seriousness of the problems. Not only a posionouss pill, but a very bitter one too. I take it now then that all Yanmar engines now have a coolant cooled exhaust manifold? Are you aware of any other diesel marine engines from other manufacturers that have a dry exhaust manifold that have either failed or been a success? I'm no expert, but surely a dry exhaust manifold on a marine engine which is installed in very tight compartments with limited air flow is a recipe for disaster, including fire?

Cheers

 

[Latestarter1]

Thank you LateStarter1 for taking the time to reply.. I was unaware of the seriousness of the problems. Not only a posionouss pill, but a very bitter one too. I take it now then that all Yanmar engines now have a coolant cooled exhaust manifold? Are you aware of any other diesel marine engines from other manufacturers that have a dry exhaust manifold that have either failed or been a success? I'm no expert, but surely a dry exhaust manifold on a marine engine which is installed in very tight compartments with limited air flow is a recipe for disaster, including fire?

Cheers

Yes BY2 and 3 have continued with water cooled manifold.

A properly designed dry manifold represents no danger. The issue is that an insulated dry manifold leaves more heat energy to drive the turbocharger instead of dumping it into the coolant making engine more fuel efficient. The issue is one of expansion and contraction which either causes manifold to fracture or manifold studs to fail.

Was always an issue on Vetus Deutz engines and now seeing it on Hyundai Seasall D170 engine.

Manufacturers either using or experimenting with hugely expensive triple wall manifolds which provide the best of both worlds.

 

[one_more_drift]

Did the vetus deutz engines suffer with sheered manifold studs? We're you involved with BY upgrade? Would be interesting to read the case study if it's publicly available?