How do I get the heat exchanger tubes out - and other questions.

Balbas

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Background - I always do my own mechanics and have run old LandRovers, classic cars, bikes etc. So I know my way around a set of spanners. I've never had to do any maintenance to a marine diesel though, and obviously there are some differences. FWiW I have done the RYA Diesel engine maintenance course.

I have an old Vetus 4.14 in my boat. In effect it's a marinised Mitsubishi generator engine, which is fine, cos that means it should last forever so long as I service it.

I nipped down to the boat today to start the service process, turned off the cooling water seacock, cleaned the raw water strainer and then moved on to the heater tubes. The manual says 'remove the alternator, undo the end caps and then extract the tubes'. Alternator came off easily enough and surprisingly so did the end cap Allen bolts - I feared they would be seized, so I was prepared to get medieval with them. The first of the end caps popped off easily enough too, but the second didn't want to know. I'm guessing that a bit of percussive persuasion with a soft faced mallet might help? And it would have to be the difficult to reach one at the back of the motor... But the big problem, even on the end where I've got the end cap off, the tube doesn't want to know - it won't budge. How am I going to get that out? I did consider making a brace and using the endcap bolt as a puller, but I have a feeling that it might strip end, and then I really am in a world of pain.

In other news, my raw water pump is leaking. It's a Johnson type. There's no seal on the end plate, should there be? Or is the leak likely to be further back in the pump? Whatever it is it needs fixing as it's been dripping on the fuel pump.
 

Balbas

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Oh, and I feel anyone has an old Vetus 4.14 knocking around, I'd quite like some bits for spares, so may offer you ££ for the whole lump.
 

Plum

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Background - I always do my own mechanics and have run old LandRovers, classic cars, bikes etc. So I know my way around a set of spanners. I've never had to do any maintenance to a marine diesel though, and obviously there are some differences. FWiW I have done the RYA Diesel engine maintenance course.

I have an old Vetus 4.14 in my boat. In effect it's a marinised Mitsubishi generator engine, which is fine, cos that means it should last forever so long as I service it.

I nipped down to the boat today to start the service process, turned off the cooling water seacock, cleaned the raw water strainer and then moved on to the heater tubes. The manual says 'remove the alternator, undo the end caps and then extract the tubes'. Alternator came off easily enough and surprisingly so did the end cap Allen bolts - I feared they would be seized, so I was prepared to get medieval with them. The first of the end caps popped off easily enough too, but the second didn't want to know. I'm guessing that a bit of percussive persuasion with a soft faced mallet might help? And it would have to be the difficult to reach one at the back of the motor... But the big problem, even on the end where I've got the end cap off, the tube doesn't want to know - it won't budge. How am I going to get that out? I did consider making a brace and using the endcap bolt as a puller, but I have a feeling that it might strip end, and then I really am in a world of pain.

In other news, my raw water pump is leaking. It's a Johnson type. There's no seal on the end plate, should there be? Or is the leak likely to be further back in the pump? Whatever it is it needs fixing as it's been dripping on the fuel pump.

Had both these problems in the past. First, the leak from the pump is most likely the seal aft of the impeller. Yes, the leak drips right onto the fuel lift pump which very quickly corrodes (aluminium housing) causing terminal damage so don't delay. There are only two bolts holding the raw water pump on so remove and overhaul it at home. Second, re the heat exchanger, you won't get the tube stack out until you have removed the other end cap. However, assuming you have removed the centre screw holding that end cap, a long steel rod pushed down one of the core tubes and tapped with a hammer should pop it off. Then, don't remove the core, just very carefully rod through each tube in situe. If they are too bunged up, remove the whole manifold and stand it on end to drive the core stack out using a block of wood and a hammer.

The end caps are difficult to reseal so do make sure all the sealing surfaces are spotless and undamaged and use new o rings.

Www.solocoastalsailing.co.uk
 

eilerts

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I have a Vetus 3.18 in my boat. Except for the number of cylinders they are probably not very different.
I serviced the heat exchanger last winter.

For the tube I recommend to use a hot air gun for a moment. I will soften it and expand it.
In my version of Vetus the exchanger house is aluminium, the end caps are brass and tube stack is brass or bronse. There is one O-ring at each end that seals glycol, seawater and air. If the pressure on the O-ring is not even you may get seawater mixed in with the glycol and corrosion in the tight fit between the stack and the exchanger house. In this situation the stack will be hard to remove. I had to "get medieval". A suitable hammer and piece of firewood helped me out. Close examination showed deep pitting where the O ring was ment meet with the aluminium.

I'm quite sure there should be a paper gasket to seal the lid of the seawater pump.
 

Balbas

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I had a spare hour or so free today, so I was able to sneak off down to the boat. I went prepared, and the heat exchanger stack is now in the boot of my car. Looks absolutely minging but I am confident it'll clean up just fine.

The raw water pump should have a paper gasket on the face of it, but regardless, I have the two lip seals and the circlip (as well as the paper gasket and a new impeller) so that'll be getting done as well.

Thanks for the help, advice and pointers all - I really appreciate the moral support,
 
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dgadee

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I had a spare hour or so free today, so I was able to sneak off down to the boat. I went prepared, and the heat exchanger stack is now in the boot of my car. Looks absolutely minging but I am confident it'll clean up just fine.

The raw water pump should have a paper gasket on the face of it, but regardless, I have the two lip seals and the circlip (as well as the paper gasket and a new impeller) so that'll be getting done as well.

Thanks for the help, advice and pointers all - I really appreciate the moral support,

How did you do it?
 

Balbas

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How did you do it?
I had been told not to batter the end caps as I would deform them. A quick inspection of the one I had been able to get off made me confident that as long as I didn't really set about it with the hammers then it would be fine. So step 1) was some very light percussive encouragement on the reluctant end cap. Once that was done I considered just rodding the tubes in situ, but decided I would have a go at removing it. So onto step 2)

The end cap bolts thread into a recess on each end of the heat exchanger. This recess is about 1/2 inch deep. So I got some threaded rod which was smaller diameter than the recess - I had to ensure that I didn't damage the threads! - put it in the recess and gently encouraged it with a hammer. A few minutes later and bingo, I was holding a very dirty heat exchanger stack.

I wouldn't 'recommend' anyone follows my technique. It's easy to damage things with hammers. I have many years of experience of fixing old LandRovers, sports cars and motorbikes to fall back on. I can usually judge how much force I can get away with applying!
 
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