rallyingden
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| posted on 7/10/09 at 07:26 PM |
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Alternator problems ( updated)
OK Engine in and I have fitted my new bracket that I made to move alternator closer to block to give clearance againts chassis rail. Trouble is the
fan belt is too big but also I have put belt on to see how much smaller I need to go and because I've moved the alternator closer the pully
follows an arc so that as one side of the belt lengthens then the other shortens and the result is that I think even with a shorter belt the
alternator will not tension it.
One possible option is to fit a smaller alternator but off what ? my current one is standard lucas on a pinto with Vee pully's
Any suggestions please
Thanks
RD 
[Edited on 7/10/09 by rallyingden]
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02GF74
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| posted on 7/10/09 at 07:32 PM |
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unless you have a flat belt with separate tnesioner, I fail to see how if the alternator was used to tension a V belt, moving the altenator to a
different position fails to tension it.
the belt runs in a tringle: crank/water pump /alternator, moving the apex of the tirangle i.e. alterntor, it has to change the perimeter i.e. belt
length.
post a piccy so I can see wot u r on about,
BTW, V belts are available in vasrisou lengths in Halfrods - pop in, graba handful of different lengths then see which ist the best, allowing a bit
for wear.
then get ya money bakc if you ahve the receipt,
done this on more than one ocassion.
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rallyingden
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| posted on 7/10/09 at 07:56 PM |
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Sorry not explaining myself properly
The issue is because the pivot point of the alternator has moved.
This is a bog standard pinto single Vee pully system NOT multi vee pully's.
Good idea about Halfords though.
 
[Edited on 7/10/09 by rallyingden]
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robocog
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| posted on 7/10/09 at 08:18 PM |
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My first bracket I made for the Zetec did just that
move the alternator, even by lots, and it did pretty much FA for the tension of the belt, just shuffled the position of the triangle...LOL
I re-made my bracket completely (and put it onther side of engine) and manged to get lucky, where it was possible to tension the belt
(was pure fluke rather than working out where the first one went wrong though)
Regards
Rob
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bigpig
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| posted on 7/10/09 at 10:05 PM |
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I did a smilar thing with a pinto using the standard alternator on my Indy.
I removed the bottom alternator bracket and got a couple of L shaped bits of metal (I think mount plates for a child's swing). Drilled these out
and made a bolt on mount. This then moved the bottom mount of the alternator to about 20mm from the engine block.
I then used the upper mount as normal and changed the belt to a standard V belt (I think 795 mm length). I used a bit of string to measure the path
then went to halfords and picked a suitable belt.
I'll see if I can get a photo of it as I didn't take one earlier in the build.
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blakep82
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| posted on 7/10/09 at 10:59 PM |
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or go to a motor factor, measure the size of belt needed and they'll get the exact length in for you
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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jeffw
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| posted on 8/10/09 at 05:26 AM |
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Do you not need to move the pivot point outside the arc of the belt ?
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rallyingden
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| posted on 8/10/09 at 07:18 AM |
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Thanks BigPig that sounds similar to what I was trying to do and a piccy would help.
Jeffw Yeah the original bracket takes the pivot point just outside the belt line but that gives problems of the alternator fouling either the chassis
down leg or the exhaust manifold at No1
It sits right with what I have made its just the tesioning of the belt thats the problem. I am looking at another design of bracket or a possible
change of alternator to a smaller one.
Thanks for all your input
I will post the solution when I find it !!
RD
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bigpig
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| posted on 8/10/09 at 05:17 PM |
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I've uploaded some photos to my archive. They are a bit poo but the bracket is the matt black bit. From above its sort of:
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Shape as the bolts to the engine block are slight offset from the position the alternator mounts on.
The belt is actually a 649mm (IIRC) belt (the Halfords part number containts the length of the belt).
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Daddylonglegs
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| posted on 8/10/09 at 07:38 PM |
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I've just come in from 't garage, and tacked up a new bracket for the alternator. I'll put a couple of piccies up on my archive when
I get a chance. Think it's going to tension OK but we'll see.
Does anyone know whether the length quoted on the belt is inside or outside? I reckon I'll need around 89cm (measured around the outside - I
used a spare lawn tractor belt to line-up the pulleys and get an idea of the length needed )
It looks like the Midget is winning at the moment......
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