Darren Groves Posted April 24, 2017 Report Share Posted April 24, 2017 So back in September last year I decided to send off my Speedo for calibration (it's a Spit 1500 speedo in a Herald) as I was getting fed up of trying to do the mental arithmetic every time I approached a different speed limit as it was over-reading by around 20%. It came back, I fitted it but the odometer and trip moved on 1 mile and then stopped, so it went straight back and was fixed with no bother and returned to me once again. When I first refitted it I drove around with the Sat Nav on for a couple of trips and the readings were pretty much spot on, all good I thought. Over the period in-between then and now the needle started to get a bit erratic at higher speeds and no longer seemed right. Out for a run yesterday and I needed the Sat Nav to get to where we were going so could check again and apart from the waggy needle, it was back to over-reading by around 20%. Now I have no idea how a speedo is calibrated, but is it possible for it to revert back to it's original settings? I have checked the 3 measurements I gave to the company to calibrate it first time round and they all came out the same. They've said to send it back and they'll check it, but just thought it a little odd.... Darren Link to comment Share on other sites More sharing options...
Qu1ckn1ck Posted April 25, 2017 Report Share Posted April 25, 2017 A mechanical speedo should have no "memory". Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 25, 2017 Report Share Posted April 25, 2017 Waggy needle is induced from the cable , this will give an over rear as it is not running freely and as it springs it twangs the disc which flickes the needle I would withdraw the inner and lubricate it graphite dust is best but a stiff grease will be ok , the proper stuff I have wont migrate up the spiral wound cable but it smells awfull. Make sure the end is fully locating, if the cable is a bit short you can screw the outer and this will change its length by winding the outer spiral in or out I would start with the cable see if things improve pete Link to comment Share on other sites More sharing options...
Darren Groves Posted April 26, 2017 Author Report Share Posted April 26, 2017 OK, will try some graphite powder. Thanks. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 26, 2017 Report Share Posted April 26, 2017 Theres not too much problem with grease , and if it does get wound up the spiral into the head just remove the inards and a careful squirt of carb or brake cleaner soon removes it but do oil the main spindle when its out , these do seize when dry or aged pete Link to comment Share on other sites More sharing options...
Darren Groves Posted April 27, 2017 Author Report Share Posted April 27, 2017 Inner cable removed, cleaned up and lubricated with the graphite powder, all back together and it's just as bad. The speedo cable connection is a clip on type on the back of speedo itself, so I will take the gearbox tunnel off on Monday to make sure it's fully home on the angle drive. If that fails then I'll have to send the speedo back for them to test, it's under warranty. Darren Link to comment Share on other sites More sharing options...
Gully Posted April 27, 2017 Report Share Posted April 27, 2017 Before sending it off, an easy test is to run the speedo (in the correct direction!) with a battery drill - that will confirm if the speedo inner workings are causing the jumpy needle or the drive cable to it. Gully 2 Link to comment Share on other sites More sharing options...
Darren Groves Posted April 27, 2017 Author Report Share Posted April 27, 2017 Before sending it off, an easy test is to run the speedo (in the correct direction!) with a battery drill - that will confirm if the speedo inner workings are causing the jumpy needle or the drive cable to it. Gully Will do! Link to comment Share on other sites More sharing options...
Darren Groves Posted May 1, 2017 Author Report Share Posted May 1, 2017 So tunnel out, drill direct on the end of the speedo cable and the needle is pretty steady. Screw in the angle drive to the cable and drill onto the angle drive and it starts to get erratic, not as much as in a real driving situation but pretty sure that's the cause. New ones used to have a reputation for poor quality, that still the case? Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 1, 2017 Report Share Posted May 1, 2017 think you may have just found that out Ha ! you can strip them down but may wreck it in the process, its just a pair of bevel gears inside , well who said that Pete 1 Link to comment Share on other sites More sharing options...
Darren Groves Posted May 2, 2017 Author Report Share Posted May 2, 2017 I borrowed and fitted a friends angle drive from his restoration project and exactly the same thing....2 dodgy angle drives? I have access to a third one, but taking out the gearbox tunnel is getting a bit tedious now..... Darren Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 2, 2017 Report Share Posted May 2, 2017 Is there enough protrusion of the inner to fully get the drive out of the angle unit ots postion is contrlled by the ferule on the inner which sits in the head unit if its short get the moles on the outer and screw it the helical wound case will grow or shrink depends which way you rotate it Pete Link to comment Share on other sites More sharing options...
Darren Groves Posted May 2, 2017 Author Report Share Posted May 2, 2017 Plenty of cable protruding, so don't think that's the issue. Darren Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 2, 2017 Report Share Posted May 2, 2017 I could post you some speedo cable grease to try just dont get it under you finger nails , its quite pungent stuff let me know pete Link to comment Share on other sites More sharing options...
Darren Groves Posted May 2, 2017 Author Report Share Posted May 2, 2017 I could post you some speedo cable grease to try just dont get it under you finger nails , its quite pungent stuff let me know pete Yes please, worth a try. Will PM you. Many thanks Darren Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 3, 2017 Report Share Posted May 3, 2017 Good will post it today pete 1 Link to comment Share on other sites More sharing options...
Clive Posted May 3, 2017 Report Share Posted May 3, 2017 Darren, have you checked the angle drives. I have had repro ones that slip. Check by locking the female end with a small screwdriver or whatever held in there and turn the other end. I don't know how they managed to make them so badly when they were made well 60 years ago and many still OK today. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 3, 2017 Report Share Posted May 3, 2017 Its on its way, use dispose gloves or get a friend to use it the odour follows you around for days we toyed with an idea to hole saw the floor and run a long cable with grommet under the carpet up to the dash think my mate Ray did this if it worked ill let you know today just an idea but it elliminates the angle drive pete Link to comment Share on other sites More sharing options...
Ben Caswell Posted May 3, 2017 Report Share Posted May 3, 2017 One of the reasons for erratic or failure of the angle drive is that there should be a substantial washer in the connection to the gear box. Otherwise the short drive cable in the angle drive bottoms out in the gearbox drive, causing it to buckle. There was a BMC service note which I have a copy of but cant manage to post a copy here. If someone emails me at <b.caswell@virgin.net> I will attempt to send them a copy for posting here. Ben Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 3, 2017 Report Share Posted May 3, 2017 Right Ray one of my members fitted overdrive to his Herald and cut a hole in the tunnel , not the floor , and used a unknown but ordinary off a triumph spare hanging up in the garage , it works fine just run cable under the carpet ....simpulze Pete Link to comment Share on other sites More sharing options...
Darren Groves Posted May 3, 2017 Author Report Share Posted May 3, 2017 One of the reasons for erratic or failure of the angle drive is that there should be a substantial washer in the connection to the gear box. Otherwise the short drive cable in the angle drive bottoms out in the gearbox drive, causing it to buckle. There was a BMC service note which I have a copy of but cant manage to post a copy here. If someone emails me at <b.caswell@virgin.net> I will attempt to send them a copy for posting here. Ben I have emailed you Ben, I'd be interested to see that document. None of the parts suppliers list a washer there. Darren, have you checked the angle drives. I have had repro ones that slip. Check by locking the female end with a small screwdriver or whatever held in there and turn the other end. I don't know how they managed to make them so badly when they were made well 60 years ago and many still OK today. The 2 I've tried and the other one I may still try are all OE and don't seem to have any play in them. Right Ray one of my members fitted overdrive to his Herald and cut a hole in the tunnel , not the floor , and used a unknown but ordinary off a triumph spare hanging up in the garage , it works fine just run cable under the carpet ....simpulze Pete May end up trying this just to eliminate the angle drive. Thanks all Darren Link to comment Share on other sites More sharing options...
Ben Caswell Posted May 4, 2017 Report Share Posted May 4, 2017 Darren I have tried to send you a copy but not sure if the attachment worked let me know and I will try again. Link to comment Share on other sites More sharing options...
Darren Groves Posted May 4, 2017 Author Report Share Posted May 4, 2017 Darren I have tried to send you a copy but not sure if the attachment worked let me know and I will try again. Thanks Ben, all received. Posted below for others to see also. Darren 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 4, 2017 Report Share Posted May 4, 2017 thats good stuff, to back it up eg Rimmers state washer 538532 must be used with new angle drives or warranty is void but it doesnt appear in it as a 'kit' and washer not shown on many other web sites Link to comment Share on other sites More sharing options...
Ben Caswell Posted May 4, 2017 Report Share Posted May 4, 2017 Thanks Darren sorry its not the best copy but that scan is my only copy haven't got the original. 2 Link to comment Share on other sites More sharing options...
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