Thursday, 15 October 2015

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.

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