I allow that fighting belt dust is a constant battle. V-belts are after all consumables. Their dust is scarcely noticed in auto engine bays. But in a BCC engine room, the evidence of the crime remains to be seen.
FWIW my fighting strategy on Zygote includes:
- Clean pulleys
As Mark of Goodspeed noted, pulley surfaces have to spotless.
I polish the v-belt pulleys once a year with 240 grit paper (if time weighs heavy on my hands, I then use 400 grit paper, but time is short and the law of diminishing returns is in operation).
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Correct pulley loads
And when the v-belts are off the pulleys, I check play in pulley shafts and spin the alternator pulley etc to check that the bearings are good. -
New and quality belts
I aver that it?s pointless buying new belts and storing them in a locker.
I buy new belts each year, fit them, and put the old belt (if it?s still good, as it usually is, in the spare parts locker and dispose of the older belt that was there). Regardless of brand and quality, the rubber compound in belts loses flexibility over time, at a rate partly determined by the ambient temperature.
I only buy quality belts. As Douglas of Calliste and Ben of Elizabeth noted, Gates produces belts of better quality than many of its competitors.
On Zygote, with its Yanmar 3GM30F, standard Hitachi alternator, and Technautics Global 12 refrigerator with engine-driven compressor, I use:
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for the engine - alternator: Gates 9380 Green Stripe XL 13A0965
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for the engine - raw water cooling pump: Gates Truflex 1190 (3L190)
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for the engine - reefer compressor: Gates 7417 XL 11A1055
- Good belt tension
The right belt tension is the minimum to stop belt slip. That minimum also means that alternator etc bearings are not stressed by excessive sideways forces.
Getting the right belt tension is not easy.
I use a pulley spreader to tension and hold tension in the belt. I can then use a Krikit gauge to measure the tension (Krikit gauges are a bit of a joke, but they?re better than the ?educated thumb? technique. Alternatives include the ?spring balance, straight edge, and rule? technique or an expensive belt vibration meter).
I use the pulley spreader to spread the pulleys until my Krikit gauge measures a belt tension of 27 kgf (60 lb.f). Then I torque the fixings.
New belts need to be retensioned after their first run, of course.
The spring balance, straight edge, and rule technique, a replacement for the educated thumb, is:
- place a straight-edge along the run of the belt;
- put the hook of the spring scale at the mid-point of the run of the belt and apply a sideways force of 111 N (11.5 kg.f, 25 lb.f) to deflect the belt;
- use the rule to measure the deflection from the straight edge to the deflected belt.
If you?re not familiar with pulley spreaders, see the attached Zpulleyspreader.jpg (about 10 KB ) to see the three spreaders Zygote has. You can make your own from galvanised steel turnbuckles and a welder.
Rudi Scholz at rudi@levidrives.com may still be in the business of making and selling (with shipping from Malaysia) pulley spreaders if you tell him what size you need (I use a #6 spreader for the engine-alternator belt, a #10 for the engine-reefer compressor belt, but I?ve never found a spreader that fit and do the job for the engine-raw water coolant pump belt). Rudi will warn you not simply to use a pulley spreader to get the maximum belt tension your arm can generate ? that?s a sure recipe for destroying your alternator bearings. You must use a measuring technique (Krikit gauge, or ?spring balance, straight edge, rule?) with a pulley spreader.
A #6 pulley spreader handles spreads of 115 ? 178 mm. A #10 does spreads of 150 - 225 mm (measure from inside of pulley to inside of pulley, using your target v-belt brand).
If you?re not familiar with a Krikit gauge, see the attached Zkrikit.jpg (about 100 KB, taken before I switched to Gates belts - the photo image is large in size, the better to see the effects of ageing on my skin) to see my right hand using Zygote?s Krikit and/or employ Mssrs Google?s big invention.
Cheers
Bil
