Z395 Alternator Belt

ogrilp400

Well Known and Active Forum User
Non-VOC Member
It was the belt supply company who suggested turning it over. When I told them of the pulley diameters that I was using they pointed out that they were really too small for a V belt and that a multi rib belt turned over to run on the flat was more applicable. If you have a look in modern cars you will see that one serpentine belt runs all around numerous pulleys both flat and multi rib.

Phelps.
 

timetraveller

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VOC Member
I've only got access to one car modern enough to have this kind of belt. It is a Toyota Land Cruiser 4 cylinder turbo charged diesel. As far as I can see under the bits and pieces all the parts which are driven or do the driving use the grooved side of the belt. Only the tensioner uses a plain pulley on the smooth side of the belt. However, as I wrote earlier, Flymo do use the grooved side on a plain pulley to allow for misalignment or flexing. Try it, but do not be surprised if it slips or you have to use excessive tension to stop the slipping and hence limit bearing life. I have in the past provided just the pulleys and belt to people who already have their own system but it is unlikely that your shafts will fit the centre holes of our pulleys and it might mean making pulleys with nothing other than pilot holes in their centres. Alternatively, as the kit we provide is not a money making scheme but rather there to help fellow Vincent riders, I can send you CAD drawings or files so that you can make your own pulleys.
 

Robert Watson

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VOC Member
I drive a 200 W P/M alternator off a jackshaft situated in the dynamo drive location and utilize a 120J6 polyV belt (12.0 inch long J section (3//32" pitch spacing??) and 6 ribs - although 4 would likely have done it but I like long belt life). I do not run it all that tight and believe that on say snapping the throttle open and shut, the belts slips some and therefore doesn't overload the sprocket/chain roller interface (OMG I've spent too much time being corporate!) acting as a torque limiter. This belt runs a speed up drive with pulleys of about 1.9 inch dia driving one about 1.4 inch dia. I was worried about belt life, always pack a spare or two, and having run this since 1993 and never having had to change a belt on the road, am starting to feel some confidence in it, I have had 3 failures during that time, twice a wire has fallen off the regulator and once the idiot light circuit (yes I know - I need one) that tells me that it is charging - failed. The unit still charged just fine and later when the ammeter internals melted (yes sitting out in 45 deg weather in Australia) jamming the needle, I had to check with an independent meter, and yes it was still charging. I replaced the reg and kept the other one as a spare, although being from a small John Deere tractor it is available pretty much anywhere in the rural world.

All this just to say that poly V belts (IMHO and having spent 20 years selling industrial power transmission stuff) work very well. I would take one over a regular v belt any day. smaller pulleys can be used, and thy give long life.

Robert
 

ogrilp400

Well Known and Active Forum User
Non-VOC Member
Alternator Drive

G'day Robert,
I'm running a similar set up to you. Although in a Norvin it has to run much closer. My pulleys almost touch. My pulleys are about the same size as yours. I too wanted a little slip in the system so in hindsight I should have gone for a multi rib set-up (either upside down or right side up) but was half way through the exercise before this cropped up. May be when the V belt craps out I will change to a multi rib. I carry a spare belt in the headlight so the way that this V belt is lasting it might be a while before I need to change.
The heat out here is still much the same. Quite pleasant at the moment but next week is forecast to be in the 40 degrees.

Phelps
 

timetraveller

Well Known and Active Forum User
VOC Member
When designing our system I phoned around some of the polyvee belt manufacturers and on one occasion was lucky enough to be put through to their chief design engineer. I told him that the load on the belt would be about one kilowatt, definitely over the top but remember that one does not get as much energy out of any system as one puts in, and that the drive would be subject to some jerkiness. He was able to feed this into his computer and immediately come up with the advice that a three chord (groove) belt would do all that we needed. Like Robert, we supply a six chord belt so we have a probable redundancy of about a factor of three. Also like Robert users do not seem to find the need to adjust the belt once it is set up properly. The only thing that I could do to improve the system is to hard anodise the pulleys but so far they do not seem to wear.
Please sir can we have some of your heat here. I was out last night in -7deg C.:confused:
 

Alan J

Well Known and Active Forum User
VOC Member
belts

I run an oldfashioned 12 volt dynamo-it is more "friendly" than an alternator!! I've had the same "v" belt[x size] for more miles and years than I care to remember!!-the alley pulleys do wear, but last about 80,000 miles or so!!:):)
 
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