odd sized alternator belt

[Gunfleet]

I've just installed an adverc controller and a larger alternator to my Yanmar 1YGM10 engine. Of course, that means the alternator belt doesn't fit. I know this is going to sound a daft question to all those engineers and mechancs out there, but how do I get a new one which fits? Okay I can measure the dimensions with a bit of cord - but then what? Go to Halfords and compare my bit of string with belts until I find one that fits? Or is there a great big chart of belts somewhere I can retreive a part number from?

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[Johnjo]

Recently had the same problem, measured the diameter with a lenght of cord,
which I took to Halfords, Guy there looked at me as if I was the local idiot when
I explained what I wanted!
Told me all they got is what is on the shelf and no I could not open it up to check the size.
Last time I ever go to Halfords.
So went to local car shop, show him what I wanted, " No problem sir" came back with a device
for measuring the size needed, soon sorted out "If it does not fit sir bring it back"
Anyway it was a perfect fit, Halfords no way ever!!!!!!!!

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[snowleopard]

your local motor factor will have a stock of belts in 5mm length increments. don't worry about what model car they fit, there are lots of us out there with non-standard belts eg my kit car!

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[dickh]

Or try an industrial supplier like Fenners or BSL - they both have branches around the country. As you are fitting a larger alternator, I suggest you fit "Cogged Raw Edge" Vee belt, recognised by the moulded "teeth" on the inside and the flanks of the belt are "cut" not wrapped round. Thesse transmit much more power than traditional vee belts. BSL or Fenner can advise on these.

<hr width=100% size=1>dickh
I'd rather be sailing... /forums/images/icons/smile.gif

 

[byron]

<font color=blue>Seems a bit unfair of you Mike to blame the whole Halfords chain because you came up against an unimaginative shop assistant. I don't blame all of John Lewis stores because when I asked for something I was told <font color=black>"You are the 5th person today I have told we don't stock them because there's no call for them"</font color=black>

<hr width=100% size=1>http://www.alexander-advertising.co.uk

 

[Johnjo]

Yes your right Byron, probably just my local branch.
Trouble is " once bit twice shy "

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[colvic]

Made the same mistake myself; you should keep the pulley off your old alternator.

Phil

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[petery]

I've also had a similar experience.

Wanted more output so I bought a Prestolite 105Amp unit from Adverc to replace my 45amp Lucas. I was told that I only needed a spacer to fit it.

I have a Lister Petter with a multiple V belt - ie 4 small V grooves not on big one so I had to transfer the original pulley - only it didn't fit and it needed a keyway cut into it.

Got the work done by a local engineering shop but found that the power needed to drive the new alternator via the smallish pulley meant that it slipped at 60 amp - even when I over-tensioned the belt. Had to have an idler pulley made to keep the belt tension high.

No complaints whatsoever about Adverc - the whole process was just not as simple as I expected.

... but I got there in the end,

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[VicS]

Among the collection of numbers printed on the belts one will be its length or outer circumfrence in mm or cm. So if you attempt to measure that dimension with your piece of string you will be able to find a belt without comparing Halfords entire stock with the string. When you've got the right one buy a spare and make a note of its length for future reference.

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[clio]

take dia. of both pulley's and centre distance apart, plus width of groove at top to any good belt outlet, they will know size you need

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[colvic]

Yes, we don't realise how much power is used driving the alternator. A Lucas 70amp on the old BMC 1500 diesel worked well but you could here the change in engine note when the controller cut in or out.

As you say, the old pulley is the best solution.


Phil

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[hlb]

These are all good suggestions. Or look up bearing suppliers in yellow pages. We buy belts all the time, for all sorts of home made machines. Cost about a fiver. Any size you want.

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Haydn

 

[Gunfleet]

Thanks all for explaining this. Even I should get it right now!

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[HaraldS]

v-belts usually have a type description describing the form of the cross section, heat resistance and so on and then a length. The length is usually measured some distance away from the inside of the pulley, quite close to the outside, where most of the force is transmitted. The prifile type picture usually decribes where exactly the length is taken. You don't have to be terribly accurate in measuring as you have some room to cover with the tensioner, but if you are on the short side, you might have trouble getting it onto the pulley.

Typical types would be XPA or SPZ for your kind of engine. Both are quite similar, one of then can do smaller pulleys as it has theeth in the inner part that can squeeze a bit more. But you need to get the 'right type'for your pulleys from the old v-belt. I would take the length measuring around the outside of the pulleys, and then round it down to the next industrial size. Say you measure 875mm, then you'd get an XPA 862.

You might find an internet shop that has the descriptions and where you can order about any type of v-belt. I only know a German one called v-belt express, they shipped to me anything I wanted in 24 hours.

<hr width=100% size=1><A target="_blank" HREF=http://www.taniwani.de>http://www.taniwani.de</A>

 

[Birdseye]

use fenner - i do so for my yanmar without problem

the yanmar belts are not the same width as standard car / van belts . on my 2 gm, i found that the 13mm x 750mm A 750 A29 fits well and lasts. my first efforts with halford car belts didnt last more than half a season if that - they slipped because they were narrow and therefore sitting on the bottom of the groove not the edges

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[chas]

Had exactly the opposite experince - I needed an odd sized belt and took the measurements to Halfords. Very helpful young man opened boxes until he found the right one.

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