NonMember Posted February 27, 2022 Report Share Posted February 27, 2022 All three of mine are on Lucas alternators. I replaced the GT6's because of worn brushes, back in the mid 90s. I swapped the Vitesse's because the regulator was getting questionable (it may have been still connected when some MIG welding was done) but then I replaced the regulator and fitted it to the Spitfire. I've also had many other Triumphs over the years, nearly all with Lucas alternators. One other (beside the GT6) has suffered worn brushes (on a high mileage car) and the TR7 had one of the mounting lugs snap off when refitting without freeing up the adjustment tube. That's all. If my Mondeo ever makes it to 30 years old, never mind 50, I'll see whether its modern alternator really is more reliable. 1 Link to comment Share on other sites More sharing options...
Peaks Posted February 27, 2022 Author Report Share Posted February 27, 2022 On 25/02/2022 at 20:01, clive said: I too had enough of lucas recon stuff, and have fitted Denso 40A alternators that are faultless after many many thousands of miles. They are OEM so should last 100K plus. This is the type I have, but beware copies, they are probably as bad as the recon or cheap copy ACR stuff. Pretty simple, will need a different belt length and a bit of fettling to fit. https://www.ebay.co.uk/itm/224837903877?hash=item3459622605:g:eo0AAOSwQuFgSPbk Thanks for all the responses, good to know I'm no the only one to suffer from cheap alternators. Clive, you've convinced me! I'm going to go for a Denso. Before I buy, could I ask some questions about the fit though? Is the pulley on the Denso the correct size for the alternator to run at the right speed? I see there are three connectors on the back of the alternator, and what looks like one large one on the side (the main power out?). I've currently (see what I did there? 😁) got three wires coming out of the back of the ACR. Could you tell me what wires go onto which terminals please? Thanks Link to comment Share on other sites More sharing options...
Iain T Posted February 27, 2022 Report Share Posted February 27, 2022 From the posts it seems the older Lucas alternators fare much better the new ones. This is the one I bought. I phoned them and said what car it was for so they installed the correct pulley. Link to comment Share on other sites More sharing options...
Clive Posted February 27, 2022 Report Share Posted February 27, 2022 46 minutes ago, Peaks said: Thanks for all the responses, good to know I'm no the only one to suffer from cheap alternators. Clive, you've convinced me! I'm going to go for a Denso. Before I buy, could I ask some questions about the fit though? Is the pulley on the Denso the correct size for the alternator to run at the right speed? I see there are three connectors on the back of the alternator, and what looks like one large one on the side (the main power out?). I've currently (see what I did there? 😁) got three wires coming out of the back of the ACR. Could you tell me what wires go onto which terminals please? Thanks I have been using teh pulley supplied. Seems to be very happy, max engine revs set to 7000rpm, the alternator has not exploded yet! (and yes, I do hit the rev limiter sometimes) The big connection will go to the thick brown wire(s) and it may be worth adding an extra 30A wire direct to battery positive, never a bad thing. The L goes to warning light wire, the IG needs an ignition live to "wake" the alternator up. The only other thing is fixing to the car. I drilled the original mounting bracket 10MM and used a bolt/spacers to get it correct. Bear in mind one is on a TR7 engone , the other an alternative" engine. But not difficult. To get the right length fanbelt either cut you old one, and use that to measuere the length, or a bit of rope etc about 10mm thick. 2 Link to comment Share on other sites More sharing options...
Peaks Posted February 27, 2022 Author Report Share Posted February 27, 2022 Thanks very much for the information and advice Clive. Link to comment Share on other sites More sharing options...
SpitFire6 Posted February 27, 2022 Report Share Posted February 27, 2022 5 hours ago, Iain T said: From the posts it seems the older Lucas alternators fare much better the new ones. This is the one I bought. I phoned them and said what car it was for so they installed the correct pulley. This does not look good. What a strange way to show output capability. Am i missing something? I would need to know the engine to Alternator speed to comment further Link to comment Share on other sites More sharing options...
Iain T Posted February 27, 2022 Report Share Posted February 27, 2022 24 minutes ago, SpitFire6 said: This does not look good. What a strange way to show output capability. Am i missing something? I would need to know the engine to Alternator speed to comment further When I phoned he did tell me the ratio of crank to alternator diameter ratio, I think it's about 3:1 Link to comment Share on other sites More sharing options...
SpitFire6 Posted February 27, 2022 Report Share Posted February 27, 2022 Hi Iain, @ engine speed of 5000, then Alternator turns @ 15000? Seems a bit high? Cheers, Iain. Link to comment Share on other sites More sharing options...
Iain T Posted February 27, 2022 Report Share Posted February 27, 2022 53 minutes ago, SpitFire6 said: @ engine speed of 5000, then Alternator turns @ 15000? Seems a bit high? Iain....is there an echo in here? I'm guessing, just need to measure the diameters and calculate. I'll do that tomorrow......if I remember! Iain 1 Link to comment Share on other sites More sharing options...
PeteH Posted February 27, 2022 Report Share Posted February 27, 2022 I am speculating that the ratio is somewhere between 1:1 And 2:1. When 5000rpm would produce 35(ish) Amps?(1:1). 2:1 would produce (approx) 45Amps. at about the 3000rpm mark?. Be intersting to know?. Pete Link to comment Share on other sites More sharing options...
Sparky_Spit Posted February 27, 2022 Report Share Posted February 27, 2022 Depending upon whereabouts you live, enquiring at a local agricultural machinery suppliers may come up trumps with a good price for a Denso alternator such as those in the pictures above. A few of us in the Essex CT group bought Denso ones intended for Kubota diggers, which fitted our Triumphs very well with a few spacers to distance them correctly, and I think that they were about £25 in the supplier's "spring sale". This was some time ago, so they might be more expensive now, but they will be much cheaper direct from an agricultural supplier. They will also be top quality too. Mine has been 100% reliable for a long time now. And I was able to use the pulley that was supplied too. Link to comment Share on other sites More sharing options...
Peaks Posted March 12, 2022 Author Report Share Posted March 12, 2022 I've fitted the new alternator and it's putting out 14.1 volts at idle 👍 However, the red ignition dash light no longer comes on when I turn the ignition on. There is 12 volts at the IG wire, the one as Clive described it, to wake the alternator up, and when I disconnect that wire from the alternator and earth it the dash light illuminates. I've also checked that the alternator is earthed well and it is. Any ideas why the light's not coming on? 1 Link to comment Share on other sites More sharing options...
johny Posted March 12, 2022 Report Share Posted March 12, 2022 I thought from Clives info L connection (your brown/yellow wire) is the warning light and the IG (green/brown) is the switched live so surely earthing the latter isnt a good idea? Link to comment Share on other sites More sharing options...
Peaks Posted March 12, 2022 Author Report Share Posted March 12, 2022 That wire is the one which is made live by turning tje ignition on. Earthing that wire just completed the circuit through the dash light, proving the circuitry to the bulb and the bulb itself is OK. At least that's how I saw it. Link to comment Share on other sites More sharing options...
johny Posted March 12, 2022 Report Share Posted March 12, 2022 Whats on the L connection then that the instructions say is 'warning light'? Link to comment Share on other sites More sharing options...
Peaks Posted March 12, 2022 Author Report Share Posted March 12, 2022 1 hour ago, johny said: Whats on the L connection then that the instructions say is 'warning light'? Voltage wise? With the ignitio on zero volts either at the wire or the L terminal on the alternator. As the light is live with the ignition on, and earth's through the L terminal I'd have expect that the L terminal would show zero, or close to zero resistance to earth when the alternator isn't running, but it doesn't. It actually shows a very high resistance, although not open circuit. That's my take anyway, I am by no means an expert or even that knowledgeable on car electrics. Link to comment Share on other sites More sharing options...
johny Posted March 12, 2022 Report Share Posted March 12, 2022 Think we need some advice from Clive as I dont know how your wiring is done but would have thought the brown/yellow wire on L would have come from the warning light. However not sure what the green/brown on IG is as I think your wiring must have been modified to fit the original ACR unit... Link to comment Share on other sites More sharing options...
Peaks Posted March 14, 2022 Author Report Share Posted March 14, 2022 Thanks Johny, your observations made me go back and check all the wiring and you were right; the loom has been modified. The brown and yellow wire going into the back of the alternator in my photo was in fact the feed to the headlights. Now I've sussed that, I've got a switchable supply going to the alternator and the dash light going to the correct terminal. I'd love to blame a previous owner for the changes in wiring, but can't; it was me, I'd just forgotten what I'd done in the past 🤦 Anyway, all working now as it should 👍 Link to comment Share on other sites More sharing options...
johny Posted March 14, 2022 Report Share Posted March 14, 2022 Great news and even better that no damage was done😅 Link to comment Share on other sites More sharing options...
Peaks Posted March 14, 2022 Author Report Share Posted March 14, 2022 33 minutes ago, johny said: Great news and even better that no damage was done😅 Quite! For anyone else making this conversion, I found a 1050 belt fits well. I did have to shorten the adjusting bracket though, to stop it rubbing against the top water hose. 2 Link to comment Share on other sites More sharing options...
Clive Posted March 14, 2022 Report Share Posted March 14, 2022 Glad that is all sorted Afraid I was away at the Club Triumph awards dinner at the weekend, all rather busy.... and no, not in the Spitfire. I had to deliver a dolomite interior! Those little denso alternators just look so tiny, but what a great bit of kit. Link to comment Share on other sites More sharing options...
Peaks Posted March 14, 2022 Author Report Share Posted March 14, 2022 29 minutes ago, clive said: Glad that is all sorted Afraid I was away at the Club Triumph awards dinner at the weekend, all rather busy.... and no, not in the Spitfire. I had to deliver a dolomite interior! Those little denso alternators just look so tiny, but what a great bit of kit. In comparison, they are tiny! The pulley is almost exactly the same diameter as the ACR though. 1 Link to comment Share on other sites More sharing options...
Clive Posted March 14, 2022 Report Share Posted March 14, 2022 18 minutes ago, Peaks said: In comparison, they are tiny! The pulley is almost exactly the same diameter as the ACR though. And it won't go wrong! Link to comment Share on other sites More sharing options...
Peaks Posted March 15, 2022 Author Report Share Posted March 15, 2022 And, it provides full charge with the engine at idle I noticed. 14.1 volts whether the engine is at 850 rpm or 4000 rpm, and the ammeter showing charge to the battery at idle even with the fan and headlights on. As you say Clive , it seems to be a good bit of kit! 1 Link to comment Share on other sites More sharing options...
SpitFire6 Posted March 15, 2022 Report Share Posted March 15, 2022 Hi, Sounds very good. What does your Ammeter show when engine is not running & all loads are on? Cheers, Iain. Link to comment Share on other sites More sharing options...
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