Belts - Again !

Discussion in 'Technical Help' started by Android853sp, Jan 4, 2016.

  1. I've been following a recent thread about belts which has prompted me to ask. Is it reasonable to run a 3rd generation Kevlar strengthened (916/748/996) 17mm wide belt on 748RS 19mm wide pullies ? The belts I currently have in my spares box are either 1st or 2nd generation and are becoming increasingly difficult to find especially as far as I am aware they have not been made since about 2005. Gates corporation have been decidedly unhelpfull about answering questions which I am not alone in finding. I'd like to convince Exige to get CCW to start making them but sadly I don't think there are enough people out there still running the RS to make it commercially viable. Another thought, what is the manufacturing process for a belt, do they "assemble" it to size or do they make a width and cut belts to size off it ? I suppose if it is the latter, I could cut down a 748R belt which is 22mm wide ? Andy
     
  2. Do you not have the option to fit 22mm pulleys at reasonable cost.
     
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  3. Talking a cost that would keep me in belts for 10 years. All 4 748R toothed pullies and tensioners, which do come up occasionally on eBay, then a fairly major lump of labour to strip and rebuild and then mess around with offset woodruff keys to get the cam timing right, then back on the dyno say best part of £1000. I'm looking for a cheap(er) fix. Andy
     
  4. Andy wouldn't you only need the idler and tensioner pulleys as they are the only ones with the raised flanges to the edges.
    Steve
     
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  5. How about a set of adj cam pullies?
     
  6. Mmmmm, I need to think about that. Now you mention it, the only thing I think I would need ensure is that the belt centres are the same. Any issue with the (slightly) higher revs ? Andy
     
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  7. Yes, went there and they come from the Testastretta which isn't compatible with the Desmo head. Andy
     
  8. I meant an aftermarket set that fits Desmo's
     
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  9. I'm pretty sure the belts aren't individually manufactured but are "sliced" off so trimming a wider one down would seem perfectly reasonable and I don't think it would be that difficult to Heath Robinson a device to do it accurately :upyeah:
     
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  10. I've seen them run on 996 belts before, even when you could still buy the RS items....
    Iirc, the cam pulleys are narrower than the R though? Might be wrong. Whatever route, make sure the idler and tensioner are compatible and your belt run should be ok. Only thing I can see maybe is the lower twin pulleys and idler spigots need swapping out to?
    I'd get a used set of 996 belts mock it up and check. Nowt to lose. If you need a set, give us a shout
    If you want to go vernier, look for late 2V pulleys on eBay. They pop up every now and then, usually cheap. Just need to build a set up....
     
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  11. Heath Robinson has got nothing on me. Curiosity is peaked now and I've got gash belts to play with :). Andy
     
  12. I love this forum. Thank you guys :upyeah:. Andy
     
  13. Agree that £1k is too much money for what, from a technical point of view, is an easy remedy. I had no idea they might be that much. Having said that what other engines use those pulleys, you could perhaps get a wrecked engine for less and harvest the bits.
     
  14. I wouldn't advise this route as a slight, even invisible nick could act as a notch point which could grow under stress, something like a small crack in a windscreen, with catastrophic results :Wideyed:
     
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  15. Thanks, fair point. Andy
     
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