JSBulmer Posted July 9, 2011 Share Posted July 9, 2011 1968 GT6 MKIGenerator - LUCAS C40L (2276E)Voltage Regulator - LUCAS 340The little car has been running quite well, until Friday. Car did not start on first attempt, but did start on second attempt (this has happened a few times when I am in a hurry). Noticed that the ignition light on the dash would not go out when it was running. Searched the various threads on Club Triumph and elsewhere and on Saturday I attempted to diagnose the problem.Could not find anything obvious so took out the meter and got these readings:Battery Voltage12.55 - engine not running12.35 - engine running at idle (800 RPM)12.18 - engine running @ 5000 RPMGenerator readings when engine running:Voltage output - 290 mVCurrent output - 40 mABeing that the generator has a maximum current output of 25 A, does it make sense that the generator is faulty when its running output is 40 mA?Anything else that I should be checking? I did not check the Voltage Regulator, besides disconnecting and reconnecting the wires.I also have a relay connected between the battery and the rest of the wiring but don't know what this would be affecting.And unfortunately I also buggered up the timing I fear. Car was running great, moved the vacuum advance and now it runs like crap. Very poor acceleration, runs smoothly at 3000 RPM and then absolute garbage above that. Think its time to go play in the distributor and reset things. Any thoughts on this?jb Link to comment Share on other sites More sharing options...
SpitNoir Posted July 10, 2011 Share Posted July 10, 2011 Hi JB.Can't completely cure your generator problem from afar unfortunately, but, as I see it, there are 3 components to the charging system that can make it stop charging.One is the generator itself of course, as you mentioned. The next is the voltage regulator. The last is the wiring between the two of them, and also to the battery (at the starter relay, if I remember).So while you might indeed have a bad generator, in need of replacing, it could be the regulator or a bad wire/connection causing the trouble. first thing I'd do is to check for loose or corroded connections, frayed or broken wires, loose mounting points to any of the above (causing a ground/earth circuit to go missing), or even a loose belt on the generator's pulley.Then the testing gets fun! There are tests and adjustment procedures to go through with regard to the regulator, to make sure it's functioning properly and telling the generator what to do. Then again, like a generator, it might just need replacing at this stage in it's life anyway.The moral of the story being, you can simply replace both the regulator and generator for a quick-n-easy fix, or not. The problem with the shotgun method (just throwing parts at it) is that doing that might not fix the initial problem because you had a bad wire somewhere.Can't tell you exactly how to adjust or test the regulator, or even if there is a simple test you can perform on the gennie to see if it's an internal fault. However, with all the extremely finely-detailed knowledge of the members hereabouts, I'm thinking it won't be long before you have your exact answer.Best of luck. Hope it's a simple solution (as in, inexpensive!) that gets you on your way again.Paul Link to comment Share on other sites More sharing options...
logicaluk Posted July 10, 2011 Share Posted July 10, 2011 there is a copy of the lucas controlbox diag out on the net, ive got a copy here but its too big to post.Dan Link to comment Share on other sites More sharing options...
JSBulmer Posted July 11, 2011 Author Share Posted July 11, 2011 Thanks GuysSpent some time alone today, just me and the little car, well actually just me and the little car's generator. Did a bunch of testing, disassembled it and put it back together again. I have various manuals on the GT6 and followed some of the testing on it and found this fine little booklet online: http://www.mgcars.org.uk/imgytr/pdf/lucas.pdf. It is a gem - download it.Definitely appears to be generator related as the output is very minimal - 0.3 V and at 3000 RPM it climbs all the way to 0.4 V (way below the 14 - 15 V it should be doing). One obvious sign in the work today is that the brushes are shot. Not sure if there is anything else wrong at this point. If I can't source new brushes on Monday then it will go to an auto electric shop for an overhaul. I get lost when the various windings come in to play and don't have the right tools for removing bearings, pulleys and the like.Will keep you posted.jb Link to comment Share on other sites More sharing options...
nang Posted July 11, 2011 Share Posted July 11, 2011 My usual advise, throw away the generater, regulater, cut out and all that rubbish and fit an alternator ;D Easy to wire up, s/h ones are cheap, and much better charging rate.Cheers Tony Link to comment Share on other sites More sharing options...
Paudman Posted July 11, 2011 Share Posted July 11, 2011 ...especially if you get one of the uprated ones that can cope with lights, wipers, heater AND CD player all at once. They're on ebay all the time. Make sure your wiring is in good nick tho. Link to comment Share on other sites More sharing options...
JSBulmer Posted July 14, 2011 Author Share Posted July 14, 2011 Shop advised that the generator needs a complete overhaul - brushes, armature and field coils are all shot.So, am in the market for a Lucas C40L generator. Does anyone have one for sale?I appreciate the comments about converting to an alternator (or a dynator), but it is not something that I am considering. I will maintain the originality of the car.Also, don't want the C40 as it is a tad bit shorter and I don't want to mess around with fittings and shims and spacers and the like.So, if you have a C40L (idealy Lucas Part # 22763E) please let me know. Yes I realize that shipping will be dear, but c'est la vis.Thanksjb Link to comment Share on other sites More sharing options...
nang Posted July 14, 2011 Share Posted July 14, 2011 I'll check the one that I have and report back. Link to comment Share on other sites More sharing options...
nang Posted July 16, 2011 Share Posted July 16, 2011 Sorry, my genny is a C40. Link to comment Share on other sites More sharing options...
JSBulmer Posted July 16, 2011 Author Share Posted July 16, 2011 Thanks Nang - much appreciated.Am sure that there must be at least one somewhere in North America.Found a shop in California that rebuilds the old Lucas gennies. So far they are an option, but looking for something closer to home since shipping could be dear.jb Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 16, 2011 Share Posted July 16, 2011 just to add a bit about the control box, TimH and I spent a day acuratley following all the manual settings voltages , gaps, currents, engine speeds and having fitted it back on feeling pleased with the result, a quick cuppa and run the tests again to be sure ,,all seemd finenext day it decides to blow all the headlamps....fit a second hand unit and bingo.....so moral is leave the little box alone have to say to keep original is very valid,but in modern driving conditions a pair of headlamps fed direct from the battery via a relay will turn the old 10v drop fed yellow lamps into 14 v whiter intensity, dont have to be halogen finish of with a alternator to keep things topped up all the time and night driving becomes more illuminating Peter Link to comment Share on other sites More sharing options...
rotoflex Posted July 16, 2011 Share Posted July 16, 2011 If John B's GT6 in Canada is like US-spec ones, it has sealed-beam headlights.Sealed-beam replacement headlights for many years have been halogens, anyway.It is interesting to read of the major operations that folks with home market cars go through to install halogen headlights, when we've been running them for a long time. Link to comment Share on other sites More sharing options...
drofgum Posted July 16, 2011 Share Posted July 16, 2011 Bill,Yes, US market sealed beams are almost universally halogen now. However most are still wattage limited to the old limits set in the days when sealed beams were the only legal headlamps on the US market. Modern separable halogen headlamps can have quite a lot more wattage now. So, it's a case of there are halogens and then there are halogens. Cheers, Paul Link to comment Share on other sites More sharing options...
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