I had a breakdown of a 2004 Volvo-Penta D6 310a where the crown of one of the pistons melted. There is no evidence of seawater leakage into the engine. Have you heard of this happening before?

post some pics
sounds like the inector went bad

We reported the issue with Volvo-Penta as a warranty claim. They sent a representative, without our consent or notice, and took several pieces of the engine to send to an injector shop to do an investigation. Hence, we couldn't take any pictures.[:@]

let us know
i'm on marinengine.com also as JUST-IN-TIME

The breakdown might have been caused by a faulty injector. Leaking diesel from the injector could have washed away the lubricating oil from the piston. Please keep us updated!

http://www.volvoforums.com/m_93662/tm.htm

Writing this from a Canadian Navy diesel shop. We are have a similar sounding problem with one of our D-6 310 hp units. pistons 1 and 6 melted crowns, gouged/scored cylinder, melting valve guides, 6000 hrs on this unit, have not tested the injectors yet and we have to find out if we have the required gear for this testing.
We had a severe blow-by problem because of the piston melting down, you should have seen the smoke!!! The high base pressures must have been pushing oil back up into the "air sep" unit and the air box and inlet manifold was full of oil and the turbo aswell of course.

Any one having similar grief?

Hi,
I have the same problem in Italy with one of the two D6 310 of my boat
They have less than 200 hours(!!) : I bought in july 2005.
We just tested the jniectors by an official Bosh technician and now we are sure that they are running good.
Therefore we must find an other cause
We are still investigating.....
Pls let me know if you have some...idea.
Thanks a lot in advance !!
max

You should really watch your Lube Oil level. There was a change from early engines not having a drain back valve in the breather line. If the engine was even slightly overfilled (see below) the oil would travel up the breather hose (choking the vent line) and enter the air box- then get sucked in. The effect of the oil hitting the piston would damage it.
Its normal to see oil there after the failure and think it was the result of losing the piston. Typically, you see the rise in base pressure that sends the oil up, but in this instance it was the culprit, not the cause. Kinda of a viscous circle really.

The issue of overfillingis a dipstick issue. I see D4's & D6's on a regular basis and my experience is the dipstick reads low, when things are actually alright.
Engines with little or no inclination, going by Volvo's spec of 5.3gal incl filters for a D6, will barely, show on the dipstick. This will play with your mind, telling you to add...thus overfilling it.
Its my opinion that you should follow the capacity, not the dipstick.