piston broke d4 300 at 420 hours

[petem]

I’d be minimising the chances of another failure.

1- Robust WIF - water in fuel elimination - review the OEM ( boat show life only filtration) consider a centrifugal filter like a racor with WIF alarms / probes , and visibility + easy drain cock .

2- minimising excess EGT . Basically running with clean props ensuring ( what ever - how ever ) they are clean every time .

Your injectors have “passed “ .New will fail with WIF and excess EGT running .

I doubt you where unlucky , you make your own luck with high speed diesels in boats .

Porto, how do you clean your props when they are in the water?

 

[Portofino]

Porto, how do you clean your props when they are in the water?

The same way when out .
Except wear a diving bottle and regulator , as I can’t breath under water , btw don’t try that Pete - and maybe wear a shorty wet suit if the water is lower than 20 degree C .
Rudders get a clean too.

 

[julians]

Porto, how do you clean your props when they are in the water?

He doesn't need to, an itama cleans it's own props by virtue of its superior Hull form.





Just joshing.

 

[Portofino]

He doesn't need to, an itama cleans it's own props by virtue of its superior Hull form.

Actually 1/2 right .
It’s not the hull this time it’s the HP .
With twin 700, s it always planes even if with grotty stern gear .
But the load / EGT ,s ( sorry guys ) are higher for a given speed .
If I can’t be arsed doing a stern gear cleanse , then I set the throttles @ 80 % load , keep the EGTs sub 600 and sit back and relax on a long trip say 24/25 knots .
As time passes the speed creeps up as the props do indeed self cleanse .
It’s the hub bit that cleans up .
It’s not the tips counterintuitively .Also the rudder immediately behind the prop wash cleans up .
This means obviously I’ve burnt a bit more fuel and there’s less to scape off later .

But crucially it’s what I don’t do , like dart off at 27/28 knots because it did that 3 weeks ago ( mid season when the water is warmer and growth prolific) .Sticks pinned Fwds tight wire etc .





Just joshing.

 

[petem]

Try to answer the question Porto!!!

 

[Portofino]

Try to answer the question Porto!!!

Thought I did !
Does this help you understand ?

 

[ari]

I am afraid Porto you will not get a high EGT on any D4 or D6 series Volvopenta engine .
The engines EVC system is constantly monitoring the propeller load by comparison of throttle position ,rpm, fuel burn, fuel temp, water temp, boost pressure and inlet air temp. It’s mainly the air inlet temp that fuels the engine.
This is all built into the ecu to protect the engine, that is the rrason why after a few months into the season the engines will not pull there full rated rpm , this is very particular on the larger IPS boats , the Princess V48 mark 2 is a pr8me example of utter dissatisfaction for most owners .
There is also an exhaust gas probe fitted just after the water injection elbow for safe measures .
Looking at the picture of the failed piston the marks do not comply with a failed injector which when failed gives momentary full fuel before the rail pressure drops shutting down the engine immediately.
The crack could be from a latent defect , in a lot of cases carrying out a post Mortem on a wrecked engine is very difficult, I have over the years acted as an expert witness examining failed recently new built or reconditioned engines .
it’s a terrible job to be involved in , they go on sometimes for years when really all the owner wants is his boat back in the water .

As the OP has stated the injections are fine and the crack is very visible I’d be going down the latent defect route .
The only other possibility is that there was some previous damage to the piston not detected in a previous ownership, which has now reared it’s ugly head.
The standard engine secondary fuel filters Water in fuel sensor is more than up to the job , it flashes up straight away reducing engine RPM placing the motor into limp mode.
Go and enjoy your boat Mr OP .

I've learned a lot from that post, thank you.

 

[Orthop]

I am afraid Porto you will not get a high EGT on any D4 or D6 series Volvopenta engine .
The engines EVC system is constantly monitoring the propeller load by comparison of throttle position ,rpm, fuel burn, fuel temp, water temp, boost pressure and inlet air temp. It’s mainly the air inlet temp that fuels the engine.
This is all built into the ecu to protect the engine, that is the rrason why after a few months into the season the engines will not pull there full rated rpm , this is very particular on the larger IPS boats , the Princess V48 mark 2 is a pr8me example of utter dissatisfaction for most owners .
There is also an exhaust gas probe fitted just after the water injection elbow for safe measures .
Looking at the picture of the failed piston the marks do not comply with a failed injector which when failed gives momentary full fuel before the rail pressure drops shutting down the engine immediately.
The crack could be from a latent defect , in a lot of cases carrying out a post Mortem on a wrecked engine is very difficult, I have over the years acted as an expert witness examining failed recently new built or reconditioned engines .
it’s a terrible job to be involved in , they go on sometimes for years when really all the owner wants is his boat back in the water .

As the OP has stated the injections are fine and the crack is very visible I’d be going down the latent defect route .
The only other possibility is that there was some previous damage to the piston not detected in a previous ownership, which has now reared it’s ugly head.
The standard engine secondary fuel filters Water in fuel sensor is more than up to the job , it flashes up straight away reducing engine RPM placing the motor into limp mode.
Go and enjoy your boat Mr OP .

will do Paul. thanks. Can you explain me what the problem of the Princess v48 is?