Kad 42's melted pistons and scored liners

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hullabaloo

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hello,
after the starboard engine melted 2 pistons and scored 2 cylinders, would you agree that the port engine can be ready to do the same?
we all know the kad 42 runs hotter because of the supercharger but does anyone know the real reason why these kad 42's melt pistons?

is there a prevention (fix / service / upgrade) we can do to the other engine rather than just wait for it to blow up on it next trip out in Easter?

thanks
 
more to bump this up a bit
I'm not a KAD 42 expert by any means but worth checking that the clutch on the super charger is engaging and then disengaging properly as the turbo boost comes in. To melt the pistons the engine is either getting too much compression or the oil cooling supply to the pistons is blocked/weak. Im sure someone smarter wil be along shortly when they spot your post
 
Hi, Not enough information to give any definitive answers, e.g. has any overhaul work been done on this engine prior to failure, has regular maintenance been carried out. Usual cause of piston melting in the Volvo Penta 41 / 42 / 44 / 300 range of engines is failure of the piston cooling oil. This is provided through a separate gallery within the cylinder block and up to the undersurface of the piston by a single jet for each piston. Cleanliness of oil and these jets is paramount to prevent possible piston melt.

Hope this gives some help.
Springer.
 
Not an answer to your question but try and get a rebuild kit which includes liners gaskets and std bearing if you can as it will save some of the cost
 
springer said:
Hi, Not enough information to give any definitive answers, e.g. has any overhaul work been done on this engine prior to failure, has regular maintenance been carried out. Usual cause of piston melting in the Volvo Penta 41 / 42 / 44 / 300 range of engines is failure of the piston cooling oil. This is provided through a separate gallery within the cylinder block and up to the undersurface of the piston by a single jet for each piston. Cleanliness of oil and these jets is paramount to prevent possible piston melt.

Hope this gives some help.
Springer.
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Could also be overpropping / overload, or injector failure.
The first thing to determine is why the pistons melted.
 
Photos please and which cylinders are the problems with?
For two to go at the same time indicates more toward the piston cooling. It's unlikely for two injectors to fail at the same time.
 
Wasn't aware there was a particular problem with this in KAD42's. We had them in the last boat and I did lots of research around them and never came up with this so on that basis I would say there is no reason to think that the other engine will do the same. I stand to be corrected of course.....
 
The early kad42 was renown for failure, the extra torque from the supercharger screwed up the engines internals, a later piston design sorted this with a change in bowl design and compression ratio.

Rebuild with a kad43 kit .

The piston cooling jet system may be faulty as it works on oil pressure from a valve, make ure the system is checked ie new valves and springs etc.
 
hullabaloo said:
is it worth putting new vales and springs in the engine that is not going to be rebuilt? is this valve on the oil pump?
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Errr no, there are valves and spring on the piston jet cooling system, as well as an oil pump relief valve.

Yes I'd renew valves in the other engine if you decide to overhaul it.
 
Hi Folks

No Volvo expert but 40 years marine engineering. A while ago a shipping co we were contracted to changed their oil supplier and instructed us to use their new engine oils in their hi speed diesels.. they supplied the equivalent spec products they said, and it was allegedly also a multipurpose oil.
Any how within 3 weeks 12 good engines wrecked melted pistons .... independent lab analysis showed oil did stay on underside of pistons long enough to absorb heat... a real bad design of a then new product from a major oil company, cost them plenty, and withdrew product from the market. so using major players in lube market does not guarantee the best product
cheers bob
 
Greg2 said:
Wasn't aware there was a particular problem with this in KAD42's. We had them in the last boat and I did lots of research around them and never came up with this so on that basis I would say there is no reason to think that the other engine will do the same. I stand to be corrected of course.....
Click to expand...

We avoided purchasing three boats because they had 42's, purely on the basis that problems with this engine are flagged all over the internet...

Go with Volvo Paul's advice - he knows
 
Cashbuyer said:
We avoided purchasing three boats because they had 42's, purely on the basis that problems with this engine are flagged all over the internet...

Go with Volvo Paul's advice - he knows
Click to expand...

I stand corrected then. Interesting thing is that I couldn't find too much at the time (bought the boat in 2005).
 
I have worked on hundreds of KAD42's since they first came out, I've always used genuine Volvo parts and oil. I've never had any piston or liner failures. This is the first one I've heard of!
 
aquatom said:
I have worked on hundreds of KAD42's since they first came out, I've always used genuine Volvo parts and oil. I've never had any piston or liner failures. This is the first one I've heard of!
Click to expand...
And there in lies the secret - uase genuine parts / oil .
Forum seems over obsessed by promoting other cheaper " OEM" parts and oils either DIY or fitted by white van man
Volvo penta go to great lengths in the manuals especially over oil spec to detail the reasons to use there stuff..
It's the first thing that sprung to my mind - wrong oil not blocked jets ,or more like jets blocks cos of wong oil .
These engines will last 1000 ,s of hours if you follow the manuel .neglect them = £££ .
 
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