Quack Posted March 5, 2022 Report Share Posted March 5, 2022 I’ve heard that if you can turn the longest run over half way it’s too loose. Also when I start my car and Rev, I get a squealing sound so I need to tighten the belt. But as you can see it can’t get any tighter? Do I just need to buys shorter belt? This one came with the alternator conversion kit so I’m a bit confused. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted March 5, 2022 Report Share Posted March 5, 2022 Squealing could be waterpump, or alternator bearings, so check just in case. You don't want the belt too tight either as this will put a strain on everything from belt to bearings. If it's floppy when you twist it like that it's too loose; a good fit will have a bit of resistance to twisting. Read the data on the outer edge of the fan belt -I can't make out what your says in the photo, just to the right of the alternator top bracket, it'll read something like 1090 (just an example) so if you think the belt is too loose with the brackets at full adjustment, try something a couple of centimetres shorter, like a 1070. Just subtract a couple of centimetres from what yours reads, it may have come with a kit but not all cars are exactly the same so by all means try a shorter belt and see how that affects things. Link to comment Share on other sites More sharing options...
Iain T Posted March 5, 2022 Report Share Posted March 5, 2022 +1 for trying a slightly smaller belt. I'm sure mine is non standard as it all depends on the alternator mounting centre to spindle pulley distance plus pulley diameter. Another option is to buy a longer bracket with more adjustment. Iain Link to comment Share on other sites More sharing options...
Quack Posted March 5, 2022 Author Report Share Posted March 5, 2022 I kept my old fan belt and I just measured, it is far FAR smaller, infsct too small to get around the alternator Hahahah. I have two useless belts! Link to comment Share on other sites More sharing options...
NonMember Posted March 5, 2022 Report Share Posted March 5, 2022 I've seen some places sell a 1050 for a Spitfire with alternator. That's too short. A GT6 needs a long one - an 1150 - which would be way loose on a Spitfire. I think the correct MkIV/1500 Spitfire belt is nominally 1088 - whether the viscous fan type needs a different one is unclear. Link to comment Share on other sites More sharing options...
Iain T Posted March 5, 2022 Report Share Posted March 5, 2022 So what size is the one on the car? As Colin said the numbers on the photo are illegible. Iain Link to comment Share on other sites More sharing options...
Quack Posted March 5, 2022 Author Report Share Posted March 5, 2022 The old has no data, here is the long one: Link to comment Share on other sites More sharing options...
Quack Posted March 5, 2022 Author Report Share Posted March 5, 2022 There is a chance that I actually don’t know how to tighten it. You see I thought the sliding bracket is how you tighten it but maybe there is a way of moving the pulleys around? Link to comment Share on other sites More sharing options...
Iain T Posted March 5, 2022 Report Share Posted March 5, 2022 That's 1063mm long so perhaps as Rob said 1050 would work? Try it. To adjust the tension just loosen the bolt on the sliding bracket (I slacken the mounting bolt as well) pull the alternator and nip up the bolt. Don't forget to retighten the mounting bolt! As it is now the alternator looks as though it's at the end of its adjustment so a slightly smaller belt is what you need. Iain Link to comment Share on other sites More sharing options...
Quack Posted March 5, 2022 Author Report Share Posted March 5, 2022 I put the old smaller Belt on, took the entire mount off and attached it back on with the belt on. Squealing has stopped, however this belt has a lot of cracks so I need to find out what length it is. Will try the one mentioned above, cheers Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 5, 2022 Report Share Posted March 5, 2022 many places have on the wall a belt measurer i had one for ages but it went up the tip after years of not needing it so you could take your fitted belt and get it measured , its not that easy witha tape measure 1 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted March 5, 2022 Report Share Posted March 5, 2022 4 minutes ago, Quack said: I put the old smaller Belt on, took the entire mount off and attached it back on with the belt on. Squealing has stopped, however this belt has a lot of cracks so I need to find out what length it is. Will try the one mentioned above, cheers Hope that has cured the squealing! You can also set the alternator to the position you want it in, allowing suitable movement to tighten, feed a length of string around the pulleys until it meets and measure the length. You may not get the exact length but pick the closest and you should still be able to move the alternator to mount to tighten. Link to comment Share on other sites More sharing options...
NonMember Posted March 5, 2022 Report Share Posted March 5, 2022 What size crank pulley do you have? The later Spitfires (which had alternators from the factory) all had the big pulley. Having looked at your photos again, you have a dynamo type adjuster bracket, so I wonder whether yours is a conversion, with the small crank pulley. That will probably be what the 1050 belt is for. Link to comment Share on other sites More sharing options...
Quack Posted March 5, 2022 Author Report Share Posted March 5, 2022 That would make sense. I converted it myself, the adjuster bracket that came with the aconversion kit was far too short so I left on the old Dynamo one Link to comment Share on other sites More sharing options...
SpitFire6 Posted March 19, 2022 Report Share Posted March 19, 2022 Alas, the days of walking into a motor factors and them able to happily find the size you need are nearly over. Link to comment Share on other sites More sharing options...
Wagger Posted March 19, 2022 Report Share Posted March 19, 2022 I used to keep a Boxford Lathe Linked belt as a spare. It's made of leather links with rivets. A bit heavy for general use and was a bit noisy. 1 Link to comment Share on other sites More sharing options...
PeteH Posted March 20, 2022 Report Share Posted March 20, 2022 Vee and Wedge belts drive on the side of the pulley. IF you have the wrong profile, or is badly worn, it will try and drive on the bottom of the pulley, with many of the results you describe. Also a wedge belt will often run in a vee groove, a vee belt will bottom out in a Wedge groove. "Fenner". back in their day, used to "hand out" a nice book, which gave all the sizes and profiles. Sadly they too are now defunct. Many places did similar. I still have a bearing equivalent book (somewhere😭). Pete Link to comment Share on other sites More sharing options...
Wagger Posted March 20, 2022 Report Share Posted March 20, 2022 The Boxford was a V belt. it 'Hummed' due to the links but fitted 'Any' car, so was useful as a 'Get me home' measure. I did try those stretch on emergency ones back in the 1980's but they shredded in ten minutes. Underpants. tights and stockings lasted longer. My alternator kit came with a different adjusting arm. At least three sizes of belt can be fitted. Maybe this would have solved Quack's problem at the start. 1 Link to comment Share on other sites More sharing options...
68vitesse Posted March 20, 2022 Report Share Posted March 20, 2022 When I converted my Vitesse to an alternator I set the alternator to the middle of the adjuster. Then cut the old belt and fed it around the pulleys and measured the difference for the one required. Regards Paul. 1 Link to comment Share on other sites More sharing options...
PeteH Posted March 20, 2022 Report Share Posted March 20, 2022 1 hour ago, Wagger said: The Boxford was a V belt. it 'Hummed' due to the links but fitted 'Any' car, so was useful as a 'Get me home' measure. I did try those stretch on emergency ones back in the 1980's but they shredded in ten minutes. Underpants. tights and stockings lasted longer. My alternator kit came with a different adjusting arm. At least three sizes of belt can be fitted. Maybe this would have solved Quack's problem at the start. My Drumond Lathe, 1945 Vintage, is similarly "belted" It runs from a countershaft, which has to be released to change gears. Poor thing could do with a large dose of TLC at the moment, but that work is very much on the "Back Burner". Pete Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now