Thursday, October 26, 2006

Drive belts

I've been spending time sorting out the various drive belts (V belts) in Lady Jane's engine room.

The main priority has been the fuel return drive belt, shown in the picture.

Drive beltsTo explain, unused diesel from the main engine drains into a tank below decks. The return pump then pumps that fuel back into the day tank above the engine, ready to be cycled around again.

For some (long) time, this pump has not been performing, and the fuel return tank is now full. This means that unused diesel has been spilling when the main engine runs. Not much I hasten to add, but nevertheless a nuisance and an unnecessary waste.

I, with Robin's help at one point, checked all the piping to make sure there was no blockage, thinking that was the problem, when the answer was staring me in the face the whole time - the drive belts were really, really loose.

It sounds dumb, I know, but it took replacing the belts on my 240 volt alternator to realise the V belts on the fuel return pump were the same type and that I now know how to fit them.

The new V belts came with a natty tool and, more importantly, instructions on how a belt should be tensioned correctly.

It looks easy in the picture, however I can promise you that messing about with these belts is not so straightforward.

The main problem being I have no bar to get the leverage necessary to turn the main engine over with human power alone, so I need to use the compressor to raise enough pressure to turn the engine using the air start system.

Fitting a belt needs two people, or lots of ingenuity, plus plenty of compressed air for those frustrating times when the belt slips on the pulley AGAIN and the whole process has to be re-started.

With the fuel return pump belts done, the return tank should now get drained and, as a bonus, I have the luxury of not needing to manually pump diesel into the day tank from the main fuel tanks.

I've also tightened the fresh water cooling pump belts, you could previously turn the pump by hand under the belts, so this will ensure the engine now runs a little cooler.

By the time I was done the tide was well on it's way out, so unfortunately I could not run the engine to ensure all was well after the belts had been re-fitted.

I still need to address myself to the seawater pump V belts, which are not nearly as bad as the others were, but this will have to wait until I get back down there with sufficient enthusiasm for another bout of dirty, frustrating, work below the engine room deck.

Right now I'm thinking "If it ain't broke, don't fix it", or is that just boat lassitude?

1 comment:

  1. Hi Tim! sorry about the previous post where I suggested an overflow pipe so that if the pump fails again any peristaltic diesel could under gravity find its way back to the main diesel tank! I have now re-read your post and all seems OK now. Good job!