Straight Six Posted March 6, 2014 Share Posted March 6, 2014 The red ignition light on my Vitesse has begun to glow dimly when the engine is running at any speed. I converted the car to a Lucas alternator several years ago.A voltmeter across the output terminal on the alternator and the -ve battery terminal shows 15 volts. I have noticed that the ammeter does not seem to show much charge even after I've discharged the battery. The ammeter reading does stay at zero with the headlights on with the engine running. The battery is new.Could this be a problem with the diode pack on the alternator, or a dodgy connection in the wiring loom somewhere?Thanks Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted March 6, 2014 Share Posted March 6, 2014 Make sure your red light bulb holder is earthed properly...one theory Quote Link to comment Share on other sites More sharing options...
JohnD Posted March 6, 2014 Share Posted March 6, 2014 Probably the earth wire from the engine.Triumph provided a manky length of braid, that often rusts away so that no one knows it should be there, or it is forgotten at some stage in restoration.Without it, the engine tries to earth to the chassis throrugh the engine mounts, no good, rubber, the gearbox mounts, ditto, via the prop shaft and the differential, also rubber mounted and the rear suspension, also rubber mounted. No wonder the alternator has nowhere to dump its charge and the light glows! I had this, and until I was running the engine in the half dark and friend showed me the glowing corona round the alternator that I realised whet was happening.Get a length of starter cable, and fix that between the engine and a solid point on the bulkhead. Don't bother with the chassis, all the electrics earth through the body. Make sure that the terminal on the cable makes good contact with BARE METAL at each end, by scraping paint away - don't rely on the bolt thread making contact.John Quote Link to comment Share on other sites More sharing options...
Richard B Posted March 6, 2014 Share Posted March 6, 2014 JohnD wrote:Without it, the engine tries to earth to the chassis throrugh the engine mounts, no good, rubber, the gearbox mounts, ditto, via the prop shaft and the differential, also rubber mounted and the rear suspension, also rubber mounted. and if all else fails, the exhaust system, clutch hydraulic pipe and the choke cable.(yes I've melted a choke cable trying to start the car) :B :'( Quote Link to comment Share on other sites More sharing options...
andy thompson Posted March 7, 2014 Share Posted March 7, 2014 Repro or Recon Lucas alternator diode packs are not exactly known for their longevity - I have been through my fair share - now I have started soldering these in to try and get some reliability http://www.ebay.co.uk/itm/Ford-Capri-Lucas-17ACR-Alternator-Rectifier-Lucas-83166E-4DS5-New-NOS-Original-/280607814346?pt=Vintage_Car_Truck_Parts_Accessories&hash=item41558772ca Quote Link to comment Share on other sites More sharing options...
piman Posted March 7, 2014 Share Posted March 7, 2014 Hello Straight Six, many years ago I had the same problem, nothing to do with earths in my case, simply a defective regulator in the alternator. £5.00 or so and a simple job to change.Alec Quote Link to comment Share on other sites More sharing options...
Andy Flexney Posted March 7, 2014 Share Posted March 7, 2014 I had a similar problem on the 3 which eventually turned out to be the Ammeter, cost me 2 diode sets before we found the culprit.Strictly speaking you should not use an ammeter with an alternator because if the ammeter goes wrong you blow the alternator.AndyF Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted March 7, 2014 Share Posted March 7, 2014 I've had the "faintly glowing charge light" repeatedly on various land rovers, in all cases the rectifier/regulator pack stopped working not long after.YMMV Quote Link to comment Share on other sites More sharing options...
Steve AKA vitessesteve Posted March 7, 2014 Share Posted March 7, 2014 AndyF wrote:Strictly speaking you should not use an ammeter with an alternator because if the ammeter goes wrong you blow the alternator.AndyFWhy is that then? Quote Link to comment Share on other sites More sharing options...
bxbodger Posted March 7, 2014 Share Posted March 7, 2014 Basics first.....belt tension! Quote Link to comment Share on other sites More sharing options...
JohnD Posted March 7, 2014 Share Posted March 7, 2014 When you think about it, really think, in terms of the whole circuit, disconnecting the alternator is EXACTLY the same as there not being a working engine earth. That is a LOT cheaper and easier to try first than messing about with diode packs.John Quote Link to comment Share on other sites More sharing options...
Hogie Posted March 7, 2014 Share Posted March 7, 2014 ....surely the red bulb holder isn't earthed - is it!!Roger Quote Link to comment Share on other sites More sharing options...
piman Posted March 8, 2014 Share Posted March 8, 2014 Hello Roger, no it is not earthed.I should add to my earlier post, the defective regulator had the alternator running a high voltage.Alec Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted March 8, 2014 Share Posted March 8, 2014 OP mentions 15v. Which is too high and will cook the battery.Don't know who is making the ACR parts now but they are utter rubbish. Try one of the more modern Lucas units - direct swap.Nick Quote Link to comment Share on other sites More sharing options...
JohnD Posted March 9, 2014 Share Posted March 9, 2014 piman wrote:Hello Roger, no it is not earthed.I should add to my earlier post, the defective regulator had the alternator running a high voltage.AlecBut the alternator IS, through the engine and earth cable.J Quote Link to comment Share on other sites More sharing options...
piman Posted March 10, 2014 Share Posted March 10, 2014 Hello John, yes of course, but so what?An earlier post said to check the lampholder earth, which is misleading as the lampholder is fed from two directions as you know. I.e., it should not have the body connected to earth, this was the question Roger asked.Alec Quote Link to comment Share on other sites More sharing options...
JohnD Posted March 10, 2014 Share Posted March 10, 2014 Of course you're right, Alec!My point was that the engine earth is an easy fix, much simpler than chnaging a diode pack and worth checking first. It solved a long standing problem for me!John Quote Link to comment Share on other sites More sharing options...
piman Posted March 10, 2014 Share Posted March 10, 2014 Hello John, indeed, proper diagnoses before firing a shotgun of parts which may not cure the original problem.Alec Quote Link to comment Share on other sites More sharing options...
Straight Six Posted March 10, 2014 Author Share Posted March 10, 2014 Thanks for all the suggestions. I made up a decent earth strap but that didn't do the trick so this evening I fitted a replacement alternator and the light is not glowing anymore, so it looks looks it was the diode pack. As an aside, the failed alternator was fitted to a scrap Mk2 2000 saloon before I removed it & fitted it to my car and I always assumed that it was a Lucas item, but on closer inspection today it turned out to be an AC Delco. Were many Triumphs fitted with these? Quote Link to comment Share on other sites More sharing options...
JohnD Posted March 10, 2014 Share Posted March 10, 2014 Thnaks, SS!Earthing 0Diodes 1It's good to know what the problem actually was!JOhn Quote Link to comment Share on other sites More sharing options...
Richard B Posted March 11, 2014 Share Posted March 11, 2014 Straight_Six wrote:but on closer inspection today it turned out to be an AC Delco. Were many Triumphs fitted with these?Quite a lot of them, between 1970 to 1974 at least. They usually have the three wires and 2 x "L" shaped connectors as the 2000 often had battery sensed AC Delco alternators., Quote Link to comment Share on other sites More sharing options...
DougBGT6 Posted March 15, 2014 Share Posted March 15, 2014 Regarding earlier discussions on alternators and ammeters, the ammeter to have in this situation is a shunt ammeter. How this works is, a very accurate low resistance shunt is inserted in the alternator to battery cable. As current flows a variable voltage is generated across the shunt proportional to the current flowing. This is applied to the ammeter which is actually a secret volt meter, calibrated to display the current flowing. I used to have one but the shunt died and you don't see them anymore, only industrial ones with LCD displays. Quote Link to comment Share on other sites More sharing options...
piman Posted March 15, 2014 Share Posted March 15, 2014 Hello Doug, there is very much less D.C. in industry now with the advent of inverters but shunt D.C. ammeters used to be very common.You are mistaken though, it is not a voltmeter as such, but simply a diversion of current proportional to the relative resistance of the shunt and ammeter. I.e. if the shunt has a ninth of the resistance of the ammeter, 90% of current flows through the shunt and 10% through the ammeter.Alec Quote Link to comment Share on other sites More sharing options...
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