Area Representative dikko Posted February 22 Area Representative Share Posted February 22 ..Oh woe is me... I'm reviving a strange Ancient Trials Car after it was abandoned for a few years after herding sheep in Wales (!) then dragged out of a hedge backwards (literally) and I'm working on the electrics. It's now got an old Healy Sprite engine of about 1200cc and it's extremely basic in the intruments dept. To help me I've just had an Auto electrician round and he said the dynamo will give me problems on my old jalopy and will cut out if I don't fit an Alternator...AAAaaggh. The good Dynamo will have to go along with the new Regulator and my lovely well-thought out wiring. (Photo pre-wiring stage) He said the fuel pump plus oil gauge and light, plus electric fan will overstretch the Dynamo power and cause the above.... I hate to be an unbeliever but Do we believe him? Fan has start-up draw of 15 amps and runs at 6 amps. It's on an automatic 82-87 degree window operation and comes off the battery via a fuse anyway. The fuel pump is a measly 2 amp draw. The Electronic ignition draw is his main concern of cutting out at low revs..The manufacturer tells me the draw is 3 amps but will have difficulty at low revs if it gets less than 6 volts. Walking pace is about the speed for Trials with the occasionally burst (either calculated or panic 😁) Oil & Temp Gauges and their lights plus sender units next to nothin' methinks. And that's all there is. Is he right? Do I go for a modern 40 amp Alternator and throw away the old technology bits? I haven't a clue as to what the dynamo pushes out or all this amperage means. My old Seven has run for years on Dynamo and Electronic ignition without a problem and it's got more electrics than this strange little beast. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 22 Member Share Posted February 22 (edited) It's a very common conversion for cars of that age. And all of the bits should be readily available for that Sprite. There's probably a worklist somewhere. The alternator will have a built-in regulator. Is it negative or positive earth? Do they swap pulley sizes on trials cars? Jonathan Edited February 22 by Jonathan Kay Link to comment Share on other sites More sharing options...
OldAndrewE Posted February 22 Share Posted February 22 My initial thoughts are that you should be OK as long as the dynamo and battery are in good condition. I had a mate that did sporting trials and I seem to recall did not run either a dynamo or alternator, just ran off the battery (with possibly a battery change during the lunch break). The original car the engine came from ran happily with the dynamo and you are not running wipers or lights I guess. Link to comment Share on other sites More sharing options...
Area Representative dikko Posted February 22 Author Area Representative Share Posted February 22 Jonathan, I know I can go buy and job done BUT... I know the Elec man might be doing 'a duty of care thing' with belts and braces but on the other hand he may be brainwashed into 'Alternators are God' too. I'm thinking it's the latter... It's Neg Earth, not sure about pulley sizes... As Andrew says (last post) some don't even have either but charge up and maybe aren't on Electronic but points but I'm not sure what the draw difference though but can't be a lot. No lights Andrew and certainly no wipers...no screen either... Link to comment Share on other sites More sharing options...
TJG Posted February 22 Share Posted February 22 Doubt you'll have problems with the current system given the minimal loads, should that be 1-3-4-2 on the coil? Link to comment Share on other sites More sharing options...
Area Representative dikko Posted February 22 Author Area Representative Share Posted February 22 From the book Tony, but I'll make sure I read it correctly...as you mention it.Ta! Link to comment Share on other sites More sharing options...
Englishmaninwales Posted February 23 Share Posted February 23 A series engine firing order is 1342 1 Link to comment Share on other sites More sharing options...
StevehS3 Posted February 23 Share Posted February 23 I have been through a similar Dynamo vs Alternator thought process for my vintage tractor. I decided on refurbishing the dynamo and replacing the original regulator internals with a solid state version housed in the original enclosure so looks the same. A blend of maintaining originality whilst making it usable. Other options are fitting an alternator as your mechanic suggested (personally I don’t like the look of modern alternators) or fitting a Dynamator which is an alternator housed in an original Lucas style housing. Example here https://www.ebay.co.uk/itm/391648227817?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Zz_MRG2qTPS&sssrc=4429486&ssuid=N1mAWR0DS2q&var=&widget_ver=artemis&media=COPY Link to comment Share on other sites More sharing options...
Area Representative dikko Posted February 23 Author Area Representative Share Posted February 23 Thanks SteveS3 and Malcolm (I WILL check!). Original dynamo I will go for I think for same reason, period looks etc. If my electrician/advisor turns out to be right a Dynamator will be done. A tractor might be thing I need for Trials except it might be against regs... Hope it goes well. 1 Link to comment Share on other sites More sharing options...
StevehS3 Posted February 23 Share Posted February 23 (edited) 1 hour ago, dikko said: Thanks SteveS3 and Malcolm (I WILL check!). Original dynamo I will go for I think for same reason, period looks etc. If my electrician/advisor turns out to be right a Dynamator will be done. A tractor might be thing I need for Trials except it might be against regs... Hope it goes well. An electronic regulator housed in the original housing would help get the best out of the dynamo. Mine charges at all times when moving ie when not idling and is set to 14.1V at 11A max. It works well. https://www.dynamoregulatorconversions.com/reproduction-rb106-and-rf95-regulators.php Edited February 23 by StevehS3 Link to comment Share on other sites More sharing options...
Area Representative dikko Posted February 23 Author Area Representative Share Posted February 23 You live and learn (from BlatChat)many thanks SS3... Link to comment Share on other sites More sharing options...
Neil220 Posted February 28 Share Posted February 28 I used many different versions of " electrical load balance calculations" during my 21 years working at Nissan in the electrical design department. I also had a 1969 mini cooper S for 38 years on which I kept the dynamo. Alternators were fitted to the rally cars to cope with the heated screens and fog/lamps but they aren't needed for a standard 60's/70's road car and you won't need one. They are more reliable and more efficient though than the dynamo/voltage regulator set up Link to comment Share on other sites More sharing options...
Area Representative dikko Posted February 29 Author Area Representative Share Posted February 29 Thank you Neil, Electric Bod gone off me, he's actually moved to Greece all of a sudden. So, before I blow up my electronic module etc I'll be looking for another, I hope I find an 'old school' one. In the long-distant past the only trouble I've had has been with Alternators the odd worn-out Dynamo bearing yes, but never regulator box or dynamo electrics. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 29 Member Share Posted February 29 (edited) On 28/02/2024 at 16:47, Neil220 said: Alternators were fitted to the rally cars to cope with the heated screens and fog/lamps but they aren't needed for a standard 60's/70's road car and you won't need one. The Corgi Rover 3500 with the glass roof was based on my father's car. The roof wasn't heated but at various times the front, rear and side glasses all were. The alternator came from a bus. Jonathan Edited February 29 by Jonathan Kay 1 Link to comment Share on other sites More sharing options...
Roger King Posted March 1 Share Posted March 1 Dikko, as the owner of an actual Sprite (Frogeye) with a dynamo, I can only say that I have never had any issues with charging. The difference is that I have a mechanical fuel pump and contact breakers, but I suspect that won't make too much difference. I assume you are not driving this "strange" car to events so my view is that you are unlikely to have problems, particularly if you fully the charge the battery before events. This does of course assume that what you have is functioning well at present. One thing I have heard of - but never had to verify for myself - is that because dynamo casings have little in the way of venting compared to an alternator, overheating problems can arise with a dynamator. Link to comment Share on other sites More sharing options...
Ivaan Posted March 1 Share Posted March 1 20 hours ago, Jonathan Kay said: The Corgi Rover 3500 with the glass roof was based on my father's car. The roof wasn't heated but at various times the front, rear and side glasses all were. The alternator came from a bus. Jonathan I’ve got that Corgi Rover in my attic somewhere. Bought with my pocket money savings when about 7-8 years old! Link to comment Share on other sites More sharing options...
Neil220 Posted March 5 Share Posted March 5 Jonathan, Are you sure the front screen was heated? I worked at Ford R & D in the 70s and 80s and they were the first company to produce a heated front screen, launched on the Orion I think. They had the concept patented and it wasn't until that expired that more recent cars have been produced with heated front screens🤔 Link to comment Share on other sites More sharing options...
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