Thursday, 15 September 2011

Some maintenance jobs 1

Instead of being able to sail Enfys during 2011 I decided to catch up on some maintenance that I was unable to carry out over the winter of 2010/2011 for various reasons..
First on the agenda was to service her engine; A 20hp 3-cylinder Beta diesel, installed by her previous owner in 2003:-

The engine was run for some minutes to warm the oil and then it was pumped out and replenished with fresh 15W40 The oil filter (out of sight under the alternator on the port side of the engine) was eventually unscrewed.  It is only about 50mm in dia and too small for my normal oil filter wrenches.  A new band type wrench that needs a 1/2" socket drive was eventually found to fit.  This now lives in the boat's toolkit, as does the special rubber-band type strap wrench I had to buy to get off the fuel filter. This is mounted in a very, very fiddly position next to the sump pump on the starboard side of the engine and is a pain to replace.

I then turned my attention to the cooling system;  Beta advises that the heat-exchanger should be stripped and cleaned annually.  We had not yet tackled this job so here goes...

Trying to drain the antifreeze I encountered the first problem;  Opening the drain tap low down on the starboard side of the block produced nothing.  The whole tap and its elbow is choked with corrosion...

I tried poking with wire, blowing back up it etc., etc. to no avail.  In the end I gave up and instead I syphoned as much of the coolant out of the engine as I could via the heat exchanger filler cap.
The heat exchanger end cap bolts were removed, raw water feed pipe disconnected and the caps tapped off. With a little bit of persuasion the tube stack was pushed out of its housing.  I was surprised to find how much scale had built up in the stack tubes and end caps.  There was also a quantity of sea weed and pump impellor fragments all lodged in there:-

I 'rodded-out' the tubes (about 25% of which were blocked) and cleaned the scale from all the parts.

An area of concern is that the tube stack and end caps are of yellow metal - presumably brass - but the heat exchanger housing is an aluminium alloy! The after end cap has a boss in which is screwed a sacrificial anode but despite its presence the after edges of the housing are deeply pitted with corrosion. This may be because of previous raw water leaks...

The tube stack was refitted and the exchanger built back up with new 'O' rings greased with Vaseline.  I then topped the system up with fresh coolant.  I really had wanted to drain the engine's coolant entirely but that will have to wait until I can resolve the blocked drain tap. Finally, a new sacrificial anode was screwed into the housing.

The raw water pump obviously needed attention.  It is a Jabsco directly driven from a camshaft extension at the front of the engine.  Ooer! On the Finesse the engine has been installed so close to the main bulkhead that I couldn't even get at the screws with my stumpy driver:-

Not having any other tools available I had no option but to remove the pump from the engine.  It is held by two clamps and nuts:-

Pump removed from engine:-

With the pump removed I took it home to my bench and took it apart to find an impellor that was coming to bits.  This was quickly replaced with a new spare well lubed with Vaseline. I had to make a new paper gasket and then re-assembled the thing.

Back at the boat I had to line up the drive spigot with the shaft dog and fiddled the pump back into place.
Now I can hear you saying 'what if the pump had failed at sea...?'.  Well, I'm also concerned about this and will be looking for an 'easy-access' cover for the Jabsco with thumb screws and a built-in cover seal...

The 'Vee' belt was tightened again, the gearbox oil level checked and control cables greased.

Fuel filter replacement has been left for now, until Enfys is re-commissioned, as I intend to drain the rest of her fuel (the tank was not topped off when she was laid up) and refill with fresh.  When she came to us there was a lot of black sludge in her tank and I had the whole lot apart during her initial fit-out in our ownership, as the tank ( A plastic Vetus 60-litre) had been poorly installed causing fuel to leak from the top and water to get in.