John Morrison Posted December 29, 2020 Report Share Posted December 29, 2020 Have come up against an issue during a conversion. Going to alternator but retaining the wide belt and dynamo pulley on the alternator, the fan belt is just too short. I did mine years ago, and didn't have any issues switching this way, anyone else come across this, or can recommend a longer fan belt, say 30mm.? Cheers, John. Quote Link to post Share on other sites
Grahamgl Posted December 29, 2020 Report Share Posted December 29, 2020 Hi John, I have the same set up. I used a slightly narrower “wide belt”, it is also a tad longer. I will Post the belt reference tomorrow. Graham Quote Link to post Share on other sites
ianc Posted December 30, 2020 Report Share Posted December 30, 2020 When 4VC was re-built (back on the road in 1993) I had alternator with wide belt. Getting the belt on to the alternator pulley was very difficult, even with the alternator rammed hard against the cylinder block. I purchased a number of belts in my attempts to find one which was a convenient length. My notes say Semperit Classic Drive 100LC (20 x 925), or Ferodo V125. However, I cannot say whether these are available now, nor whether they offer a convenient fit - the mists of time have descended! In 1998, I had a water pump failure and took the opportunity to change to narrow pulleys and belt, thereby resolving all my problems with belts. I would recommend this path as the alternator will spin somewhat faster (they are built to do this, and will give even greater output at low engine speed), changing the belt is so easy (doesn't jam because it's narrower) and the spare belt can be folded (takes less space). Years ago, I gave away my collection of wide belts. Ian Cornish Quote Link to post Share on other sites
RAHTR4 Posted December 30, 2020 Report Share Posted December 30, 2020 Hi John, An original wide belt has the following sizes : 975 O/D - 900 I/D - 20 wide top - 12 deep - 12 wide base I too kept to the wide belt and found a longer item with Revington : Not Measured O/D - 985 I/D - 20 wide top - 12 deep - 12 wide base Optibelt VB 20 x 1000 LI 10 with Revington part number RTR 5034X Have you fitted the alternator with a smaller diameter “wide” belt pulley...? I could not find one off the shelf so had to have some turned up by a local machinist who used a suitable alloy. At that same time I found that the Moss conversion kit was not correctly formed, the main joggled plate was all wrong and the alternator sat skewed out of line, so I manufactured my own design from plate and tube which gave proper alignment and a better range of adjustment. Regards, Richard Quote Link to post Share on other sites
Grahamgl Posted December 30, 2020 Report Share Posted December 30, 2020 Hi John, The belt I have on my car is a PIX xt’ra BX36/x 17x914 L1 and it is a toothed belt. I am using the old Dynamo pulley, the belt has been on my car for something over three years and I have had no problems with it. Graham Quote Link to post Share on other sites
John Morrison Posted December 31, 2020 Author Report Share Posted December 31, 2020 Many Thanks Guys. ATB for 2021. John. Quote Link to post Share on other sites
Andy Moltu Posted December 31, 2020 Report Share Posted December 31, 2020 What's the availability of quality wide belts? I am not sure what the reluctance to convert to thin belt should be? On a low revving tractor engine wide belts are fine but in 25 years of driving in convoy around Britain and Europe the only delays related to fan belt failures have been on 4 cylinder cars running wide belts. Often a git to change at the roadside sometimes involving jacking up the engine to get the mew belt on. For me the thin belt conversion is a no brainer. They fail less often and are easier to change. Going to the extent of machining an alternator pulley to take a wide belt when many alternators come with a thin pulley already fitted and off the shelf crank and water pump pulleys are readily available. If you are seeking originality then that's fine but that doesn't sit well with an alternator. Quote Link to post Share on other sites
RobH Posted January 1, 2021 Report Share Posted January 1, 2021 (edited) As Graham says above, a modern 17mm BX profile 'cogged' belt works well Andy - I have used one for 10 years with no problems. Being only 11mm tall they are easier to fit as well as being a lot more flexible than the original solid belt. (not necessarily this length - picture example only:-) https://www.bearingshopuk.co.uk/bx35-cogged-v-belt/ No point in changing the main and water-pump pulleys until you have to strip the engine for other work IMHO. Edited January 1, 2021 by RobH Quote Link to post Share on other sites
John Morrison Posted January 1, 2021 Author Report Share Posted January 1, 2021 7 hours ago, RobH said: As Graham says above, a modern 17mm BX profile 'cogged' belt works well Andy - I have used one for 10 years with no problems. Being only 11mm tall they are easier to fit as well as being a lot more flexible than the original solid belt. (not necessarily this length - picture example only:-) https://www.bearingshopuk.co.uk/bx35-cogged-v-belt/ No point in changing the main and water-pump pulleys until you have to strip the engine for other work IMHO. That was my veiwat the time, and it worked well, i.e. alternator with dynamo pulley and wide belt. Eventually with other work I did go to narrow belt, but I've never had a problem with either. John. Quote Link to post Share on other sites
John Morrison Posted January 14, 2021 Author Report Share Posted January 14, 2021 Just an update, belt issue solved thanks to recommendation here.-BX36/x 17x914 Thanks all. John. Quote Link to post Share on other sites
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