Starter motor problem

On several occasions over the last few months, Patience's starter motor has failed to engage and turn over the engine.  Rather than the engine roaring into life, only a rather unsatisfactory click emanated from the starter motor solenoid when the ignition key was turned fully clockwise.

This was diagnosed as either a low battery, loose battery contacts, a fault with the solenoid or the motor itself.  The first cause was eliminated by checking the battery state of charge, which was fine. The second cause was also eliminated by checking that all the battery connections were tight and in good order - they were.  I then disconnected the cables from the solenoid (photo 1) and removed the solenoid from the starter motor.  There was a slight looseness in one of the the electrical connection studs on the top of the solenoid (photo 2) which was corrected by carefully tightening the lower of the two nuts on the stud (not shown in photo 2 but just visible in photo 1). Unfortunately, it's not possible to take the solenoid apart, as it appears to be a factory sealed unit, so it wasn't possible to check the condition of the internal contacts.

Solenoid in place on the starter motor

Solenoid removed, showing electrical connection studs

After cleaning the studs and spade connectors, the solenoid was replaced on the starter motor and the electrical connections restored.  Although I hesitate to claim that the problem has gone away, to date it does seem to have done the trick.

Servicing the glow plugs

The glow plugs are essential for starting the engine from cold and we normally switch them on for about 15 to 20 seconds before turning over the starter motor on the BMC 1.8 litre engine.  Two of the glow plugs can be seen just below the fuel injection nozzles in the above photo of the starboard side of the engine. As it's some time since the glow plugs have been checked and it is recommended that they are removed and cleaned after every 600 hours of running, I decided that this task should be undertaken as part of this year's annual engine service.

An 8 mm spanner is needed to undo the cables from their terminals (don't lose the plain washers between the nuts and the spade connectors!) and then a 12 mm ring spanner is needed to unscrew the plugs from the engine block.  It is unusual to find metric parts on the BMC engine; most of the nuts and bolts require A/F spanners.  Accessibility is limited, particularly in the case of the front cylinder glow plug, which is tucked away in an awkward position behind the alternator.  The task would be made easier with a ratchet ring spanner (not a socket spanner, as the plugs are too long), although it can be done with a simple ring spanner and a modicum of patience. If it is some time since they were last taken out, the build up of carbon may make their removal more difficult, but do persevere, as they will come loose eventually with a little gentle encouragement. You may need to keep turning them, even after the thread on the plug is clear of the tapped hole in the block.

Patience's glow plugs were generally not too carbonised and were easy to wipe clean, and all registered a resistance of about 1 ohm.  This corresponds to a current of 12 A per plug (48 A for all four) or 144 Watts per cylinder at a nominal battery voltage of 12V. However I did notice that the centre terminal of one of was slightly loose in the housing.  I ordered a replacement from Calcutt Boats and it arrived in the post less than 48 hours later - fantastic service. The resistance of the new plug was a little higher at 1.4 ohms, which is either a specification change or the build up of dirt on the old ones may be lowering their resistance slightly. 

Before replacing the plugs in the block I inserted and rotated by hand the recommended 11/64 in (4.37 mm) diameter drill into the holes to clear any carbon build-up.  It is a good idea to coat the drill with grease so that the carbon particles can be removed on the drill rather than falling into the cylinders.

Annual Engine Service

As it's nearly four years since the antifreeze was changed (see 5th December 2011 blog) and as it only has a recommended life of 2 years, we decided it was time to drain the water system and refill it with Triple QX Blue Antifreeze obtained from Euro Car Parts in Cambridge, which used to be Unipart. The cooling system has a total capacity of about 31 litres including the swim tank, so 15 litres of antifreeze gives almost a 50% mixture - good enough for the harshest of English winters.  As before, the system was drained by disconnecting the bottom hose from the swim tank and draining the system into the engine bilges, from where most of the coolant can be pumped into containers using the bilge pump.  The last few litres have to be sponged out, wearing rubber gloves to avoid skin contact with the ethylene glycol.

We poured the 15 litres of new antifreeze into the filler cap (using a length of rubber hose attached to a funnel) and then topped it up with about 16 litres of water.  Running the engine for a while allows the antifreeze and water to mix thoroughly and gets it warmed up for the next job - changing the oil. It's important to check the water level after running the engine for a few minutes, as further topping up may be needed. Also the bleed nut at the top of the swim tank must be used to release the air lock that is created in the top few cm of the swim tank.

Changing the oil and oil filter is very easy on the BMC 1.8 engine, as it is fitted with a sump pump that enables the oil to be pumped out into an old oil container for subsequent disposal at the recycling centre, along with the old coolant. So far, so good!

The next job was to change the fuel filter.  This is when the fun started!  For the past 5 years I have successfully bled the new fuel filter by slackening the unused blanking plug (behind the copper pipe in the above photo), followed by the union nut at the very top of the filter housing, as described in the Calcutt BMC Engine Operator's Handbook, which can be downloaded from their website.  However, for some inexplicable reason (short memory and the end of a long day), this year I followed the instructions in the BMC official engine manual.  This manual makes no mention of bleeding the top union nut on the filter housing, but instead recommends bleeding the fuel line from the filter to the injector pump at the point where it enters the pump.
When I subsequently started the engine, it ran for a few seconds and then died, as the slug of air still trapped in the top of the filter housing worked its way through to the injectors!  That meant the whole injector pump and the high pressure fuel lines to the injectors had to be bled. This is not an easy job, which on this occasion was made even more difficult by one of the bleed nuts (on the injector pump anti-stall valve) shearing off as soon as I went anywhere near it with a spanner! I removed the whole of the anti-stall valve assembly, shut off the fuel valve at the tank and went back to base in a somewhat frustrated mood.
The next morning I 'phoned Calcutt Boats and ordered a new valve assembly, which arrived first thing in the post the following day (really great service, Calcutt - thank you). This morning we returned to Patience, fitted the new valve assembly and systematically bled the whole fuel system, including the high pressure pipes to the injectors. The engine still stubbornly refused to start, so the whole procedure was repeated.  After heating the glow plugs for 30 seconds, more than the 20 seconds normally required for a cold start, and cranking it for a while, the engine finally spluttered into life - hooray!

The final task was to inspect and adjust the tension on the alternator drive belt.

Tanks and tappets

With moderately fine weather first thing, we motored over to Oundle marina to do a few more winterising tasks.  The diesel tank was topped up to reduce the likelihood of condensation over the winter.  We were reassured by Mark in the office that he pre-treats all the marina biodiesel, so we don't have to worry about any additives.  In the short journey to the fueling stage we managed to pick up a short length of rope (someone else's) around the prop shaft, although it didn't seem to slow Patience down too much.  We also noted that the o-ring on the filler cap needs replacing, so it was measured up to get a replacement.

Having returned to our mooring, it was off with the rocker cover to check the valve clearances.  According to the BMC manual. 1.8 litre engines with a 'later type' camshaft should run with a clearance of 0.014 in, measured hot or cold.  You can tell if you have a later type camshaft by looking at the side of the lower engine block - if it has ribs you have the later type camshaft.  Turning over the diesel engine to close each of the valves in turn is difficult, as the gearbox doesn't engage if there is no hydraulic pressure and you can't apply enough torque on the nut on the front end of the crankshaft to turn it.  In the end, we turned the engine over briefly on the starter and tried to avoid it firing.  Note for next time: this would be easier with the engine cold so that it doesn't fire. Most of the clearances seemed to be fine, but three needed adjusting to reduce the clearance to the designated 0.014 in.

We checked the gas fridge, which had been giving problems failing to ignite in the summer, but today seemed to fire up first time.  That may be because it's much easier to see the pilot light in the gloom of a winter's afternoon. We don't want to spend £500 or more on a new fridge if we can avoid it.

Finally, we measured up the effluent tank as a prelude to possibly investing in a resistance type depth gauge.  It's the one tank on board where a little technology would pay dividends.  Unlike the fresh water tank (which you can see into) and the fuel tank (which you can put a dipstick into), those solutions aren't a pleasant option for the black water tank!