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Narrow Belt Conversion (again, I know)


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As always, one job leads to another.

I had always assumed that sometime in the future I may want to consider: Alternator, Narrow Belt, Electric Fan conversion, preferably one at a time. But ideally not just yet as I have loads of other things to do which are more important.

However, my dynamo is showing signs of bearing wear so I had to deal with it and had the choice of reconditioned/new dynamo now or go for an alternator. Thinking that of each of the three things above the alternator conversion is probably the most sensible, I'll do that now.

So the plan was to install the alternator with the existing thick belt. I have seen a YouTube video of a guy doing just that. So I bought the alternator, mounting kit and wiring.

When the alternator arrived it already had a thin fan pulley on it. Problem 1: I cannot get the new pulley nut off the alternator to put my old one on - it appears massively tight and there is no easy way to stop it rotating without damaging the alternator. Potential problem 2: even if I could get it off without damaging the alternator I don't know if my existing pulley will actually fit on.

So (unless someone can help me with the above problem), plan B is to go for the narrow belt conversion now, which is perhaps the right thing to do anyway. Can anyone advise on the following:

A. As my new alternator already has a narrow pulley on it do I just need to buy narrow crank pulley and narrow water pump pulley (as listed by e.g. Rimmer, Moss) rather than the full kit, and does that mean it will be 'undamped' - and will my existing fan fit back on - for now at least?

B. How difficult to fit? It looks like I could probably access the crank pulley without removing the radiator - is that so? Do I need to take the main crank bolt out, and if so how do I lock the engine to do this.

I known this is a very well trodden path and have read plenty of stuff on this and other forums, but can't actually find any step by step instructions for this.

Thanks for any help.

Alistair.

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Alistair,

I ran an alternator with a wide belt and dynamo pulley for several years, before eventually going the narrow route.

There is no problem with the wide belt.

Best way to hold the narrow pulley is wrap it with rope, and the grip it in a vice  so that the vice closing 'Nips' the last part of the wrap.

 

John.

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Hi Alister

You can hold the pulley in a vice and undo the nut if your going to run with a wide belt for a while. As for the narrow belt conversion I used the un damped version and removed the metal fan and extension which does nothing in relation to crank damping by the way, and fitted a pusher electric fan. You will need the short crank bolt kit from moss as well as the belt conversion kit

Chris

I do have an almost new dynamo ( less than 2000miles run) if it helps and a spare 14inch electric fan  

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You may need a 'bearing puller' to get the alternator pulley off Alistair, otherwise you might damage something by levering

As John says it will work perfectly well with a wide belt - I run just that set-up using a flexible 'cogged' 17mm raw-edge belt instead of the rather stiff standard item, though I do have a custom-made wide alternator pulley rather than the one from the dynamo.  

pulley.jpg.e0db4aa884511d0b650c89d8bc74d1ff.jpg

If you go for a narrow belt you will probably still need a puller to get the waterpump pulley off. Yes you will need to take the crank pulley bolt out and that should be very tight. Put the car in top gear, handbrake hard on and chock the rear wheels.  You will need a long breaker bar for the socket. Same set-up for doing it up again to 120 lbf.

Edited by RobH
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Hi Alister

My alternator has a pulley in two pieces, so i have wider the pulley.  an other plus is that it is easy to fit the wide belt.

No special mounting set needed.... just the right alternator....

Marcel.

 

 

 

alternator IMG_4531.JPG

alternator IMG_4532.JPG

Edited by Quicksilver
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So, I tried again to get the nut off the pulley. I attach a picture of the alternator together with its instruments of torture.

Those with a keen eye will note the injuries I inflicted on the fan part which at some point yesterday I held in the vice. John, I tried the rope trick but to no avail; Chris, you will see that the pulley is plastic, so after damaging the fan I though it best not to put the pulley in the vice.

I tried the breaker bar approach and the short sharp shock approach. I suspect that the manufacturer just assumes the pulley is on for life and assembled it as such. Perhaps a powerful impact tool would get it off, but I think risk of damage is to high.

So, onwards to plan B thin belt conversion. Probably off to Rimmer next to get thin crank and water pump pulley and belt.

Any advice on whether I should be able to do it with the radiator in place?

Thanks.

 

20210416_101022.jpg

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Not sure about the water pump pulley either. Probably safer to remove it. What TR is it, more difficult if a sidescreen.

Bob

Edited by Lebro
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Ali,

 

if thats the rope you tried, then its too small, you could try an old fan belt, ask if you want a photo, also, that nut isn't a left hand thread is it?

Be aware, going down the total thin belt route is not the easier option, for you.

John.

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Hi Alister

No you will need to remove radiator, in the kit you will get a new aluminium alternator pulley so if you damage the pulley you have already have its not a disaster you may be able to get a local garage to buzz it off with a air gun if you ask nicely the fan blades are easily re-bent. The water pump pulley may need to be pulled and the replacement may need the hole slightly enlarged I used a rotary tool but don't go too mad still needs to be a tight fit ( be careful and check as I believe there's 2 different shafts ones tapered and ones parallel ) I didn't use the damped version but the bottom/crank pulley is a bit more involved to fit I'm sure someone will guide you if you have to fit one. Also you will need to space the alternator when you refit to line up the belt ( fitting kits are available)  and possibly fit a home made heat shield at the back of it 

Chris    

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+1 for using a fanbelt - that's how I did it, looped tightly round the pulley and nipped up in a vice as close to the pulley as possible to force it together and get it gripping really tight.  The thread isn't usually left-handed.

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Hi all and thanks for your replies. Just an update.

So, in for a penny ... as they say, I decided to go the whole hog and do narrow belt and electric fan along with my new alternator.

John and Rob, I'm sure if I persisted with your advise on how to get the alternator narrow pulley off it would have worked, but my friend Trchris from this forum offered me a spare electric fan and help to fit it. So I decided to get the two other narrow pulleys and go for it.

After a bit of faffing around with the alternator it fitted quite well and luckily the new water pump pulley slipped on perfectly just requiring the nut to pull it as a tight fit onto the shaft.

Chris came over today, and I'd like to say he helped me do the rest (crank pulley, fan, electrics), but the truth is my part was to make him coffee and hand him the odd spanner. Thanks ever so much Chris - truly great people to be found on this forum.

Out for a spin to a local pub this evening and I swear the engine was smoother and quieter, but even if it is all in the mind it's still good.

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