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more boat stuff... this gives me the jitters.

outdoordan

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Too many projects as usual means i'm now rushing to get the boat finished for mid/late April (yeah right).

Anyway... the engine is a Penta MD2 with a Bosch Dynastart ... a pretty robust started/charger combo but with a pretty feeble charging capacity (prone to overheating and not really capable of charging anything over 100ah)

So I'm looking at fitting an alternator. Seen various fitting schemes, the most involved looks like fitting a new pulley to the crankshaft on the outside of the flywheel.

Then I came across this...


where the alternator belt runs round the outside of the flywheel. it looks dodgy as hell, but easy to install.

anyone think this is ok?

my guess would be you'd only need to loose a tiny bit of tension or alignment and the belt would be off; gets trapped inside (by one of the dynastar belts) or snags on something on the outside then crash bang wallop and you're getting towed home.

or is it ok? i'm pushed for time and i'd go for this if I was reassured it's safer than it looks.

it would not be unusual for me to miss something really obvious.

thanks
 

Shayne

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While it appears theres no flange to keep the belt on google images suggests to me the belt runs in a groove .

1615374142528.png
 

outdoordan

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that looks a lots safer...

there are two belt grooves on the inside of the flywheel which take the two dynastart belts.

there aren't any other grooves. the rest of the face of the flywheen is smoth, but in the photo below the alternator belt is much further from hte forward face of the flywheel... but it looks as if the alternator mount is different.

There is an alternator pulley which bolts onto the face of the flywheel but I cant find a part number or a PCD for the holes anywhere.

If I can find a pulley I'll go down that road I think.
 
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outdoordan

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funnily enough a coupling of theirs is on my shopping list. just found an alternator and pulley on facebook for £30
 

Shayne

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Their couplings might be good for your boat but with two 115hp engines in mine i bought 8 of the buggers last year , in consequence of poor engine alignment and my not being able to get there and punch anybody i'd say .
Because i bought two Sigmadrive to fit instead upsetting the gravy train the last fitted R&D are still going strong 5 months later . I will fit the Sigma myself when i can and expect years out of them .
 

Grimbo

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Only comment I would make is the 2 different alternator conversions shown would also drive the alternator at very different speeds at the same engine revs....
I know one should never presume but if you spend most of your time puttering along so to speak you need your alternator to be providing a good output at those revs
so ratio of driven and driving pulley may be important .
 

IRLGW

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Have you room to fit a shaft PTO? It's not unusual to clamp a pulley on to the shaft unless you are on a saildrive. You could fit a dual pulley and run a clutched emergency bilge/deck/fire pump off it as well.
 

outdoordan

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thanks for responses. funnily enough i found an oem alternator pulley (bolts onto face of flywheel) and alternator for sale on facecrack for £30.

Having a rummage through the shed the other day and I found a spare 70 series 12v alternator as well.

might fit one of those clever voltage thingies to get the full whack out of the alternator... its going to be charging 220ah deep cycle battery I think, with a constant solar pv dribble.
 
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