Lombardini Heat Exchanger removal

[Moonshining]

I know there are a few people who have/had Lombardini engines in their boats so someone may be able to help.

I'm trying to remove the heat exchanger from my 702M. The engine is overheating and, removing the end cover from the exhaust side of the exchanger, I can see the tubes are heavily calcified.

However, I spent hours yesterday trying to remove the cap on the inlet side with no success.

The user manual says to remove the thermostat housing first. However, the manual also seems to indicate that it's a single bolt holding on the thermostat and I've removed that, but it's clearly not budging. I've also removed the two bolts that I can see from the heat exchanger cover, but that's going nowhere either.

Has anyone successfully done this and can point me in the right direction?

 

[crown22]

I have the same engine although most of it's hours have been on freshwater.The manual offers some instruction about removing the tube nest but seems that it's not offering sufficient information.Can you not clean one end with the tube nest in situ?Might
be worth emailing Lombardini?How many hours has your engine done by the way?Good Luck either way.

 

[Moonshining]

I have the same engine although most of it's hours have been on freshwater.The manual offers some instruction about removing the tube nest but seems that it's not offering sufficient information.Can you not clean one end with the tube nest in situ?Might
be worth emailing Lombardini?How many hours has your engine done by the way?Good Luck either way.

I could probably improve things a bit by cleaning up one end of the nest and the build up in the exhaust, but I'm not sure how far down the nest the clag extends. It's only done about 350 hours, but it's over 12 years, so it's had plenty of time to fur up.


The worst build up is in line with the outlet, so cleaning the cover up properly and the end of the nest would probably get me by. I'd like to do a proper job though if possible.



I've been looking at the line diagrams of the engine and there does seem to be a second bolt between the thermostat and the radiator which may be the one I need to remove although I couldn't find it yesterday. (There's not much space around the engine, so I was doing a lot by feel and pictures on my phone.) I'll give it one more go next time I'm down there and if I can't sort it out I'll have to get someone to take a look.

 

[crown22]

Have you made any progress since your last posting?Was interested to know what temperature your engine ran out before the overheating arrived a nd what the temperature reached before you decided on a strip down.My boat is out of the water now but I seem to remember that the temperature stayed at about 85C.Thanks

 

[crown22]

Forgot to mention that I got into a lot of trouble removing the nest on a VP2040 Volvo a couple of years back.A previous "mechanic" had probably
damaged the housing by levering out the nest with a screwdriver.I posted some pictures at the time if you do a search.The nest can be very tightly trapped inside the housing.