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Rdover
Joined: 26 Nov 2007 Posts: 413
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Posted: Wed Apr 11, 2012 10:53 am Post subject: Converting Magneto ignition to coil ... |
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I have embarked on what I hope will be a reasonably straightforward conversion of my 1912 4 cylinder sidevalve engine from magneto to coil using the kit from www.austinrepro.com
First, why?
Magnetos are, in my experience, crap! The car is easy enough to start now I have the mechanical timing sorted but the spark from my mag was so flaccid and weak that it was barely climbing hills. Buying a better mag cost me £500 and then I realised I'd have to butcher it (rendering it unsaleable) to make it fit. My 'original' magneto has been rebuilt twice in 4 years and has failed twice.
The cost of the conversion, which is 100% reversible, will be about £500 all in which is about the price of a good magneto rebuild and will be totally reliable, make starting and running much easier (they claim).
Second, how?
I've sent my magneto to Austin Repro for them to assemble the kit complete with correct distributor and a bespoke coupling to match the unique one on my car. When I get the kit back I will get the car running, then use an ammeter to determine the running current draw in order for me to choose an appropriate battery set up to give me at least 12 hours running time between recharging. I may use a solar trickle charger as a top up/life extender.
I realise this is not an authentic set up but it is totally reversible and should make the car so much more useable that it becomes proper fun AND will not cost any more than having a repaired unreliable system.
I hope to get the kit later next week, fit is over the weekend and ready for its first proper run out at the Museum of Rural Life (East Kilbride) annual classic car show on 6th May. _________________ Richard |
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Wed Apr 11, 2012 12:54 pm Post subject: |
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Hi Richard
The kit will probably have a 3 ohm coil, with the points closed this would draw 4 amps from a 12 volt battery, if to make the maths easy we assume the dwell time is 45 degrees, the average current draw will be 2 amps.
Lead acid battery amp per hour discharge rates are quite predictable at lower currents, so a 40 Amp ph 12v lead acid battery should give you the thick end 20 hours use, certainly a reliable 16-17 hours.
You can purchase a small solar trickle charger for less than £10, these have an output of about 0.1 Amp, may not sound like much, but I doubt you will be driving continuously for long periods, so a good investment I would think. If you for example drove to a show, 1 hour drive there and 1 hour back, 10 hours stationery, assuming a 100% charge at the start;you would have 95.1% charge left when arriving at the show, 97.6% when returning from the show, 92.7% when arriving back at home.
I think any mod like this that is reversible is ok
Keeping aircon use to a minimum will also prolong battery life
Dave
Last edited by ukdave2002 on Wed Apr 11, 2012 1:19 pm; edited 1 time in total |
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Rdover
Joined: 26 Nov 2007 Posts: 413
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Posted: Wed Apr 11, 2012 1:03 pm Post subject: |
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ukdave2002 wrote: | Hi Richard
Keeping aircon use to a minimum will also prolong battery life
Dave |
Damn, the damn thing is stuck on maximum. Must find a work around
I was hoping to run with a 12Ah bike battery, but a small leisure/deep cycle battery may a better option as it will cope with deeper discharges better.
Cheers _________________ Richard |
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Rdover
Joined: 26 Nov 2007 Posts: 413
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Posted: Wed Apr 11, 2012 1:56 pm Post subject: |
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ukdave2002 wrote: | Hi Richard If you for example drove to a show, 1 hour drive there and 1 hour back, 10 hours stationery, assuming a 100% charge at the start;you would have 95.1% charge left when arriving at the show, 97.6% when returning from the show, 92.7% when arriving back at home.
Dave |
Just re-read this ...
Veteran car use is slightly different. We tend not to go to static shows but rather use the cars for pootling around the countryside. A typical weekend will be 50 to 70 miles each day, 90 mins to have morning tea, another 90 mins to the lunch stop, then again to afternoon tea and finally back to the hotel for a wee snooze before dinner.
Most Veteran car owners are verging on the veteran themselves and tend not to rough it. Add in that a car like mine is comfy to sit in but can be a tough thing to gad about in. I'm in a state of abject fear and panic most of the time! _________________ Richard |
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Rdover
Joined: 26 Nov 2007 Posts: 413
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Posted: Wed Apr 11, 2012 2:06 pm Post subject: |
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Just spoke to Willie at Austin Repro who told me that the photo on his website shows the old version of the conversion. It now has a vertical distributor which is easier to maintain, more reliable again and makes setup un piece de pee ... allegedly.
My odd coupling (which he claims to be a standard 15mm coupling!!) will be replicated so I have a magneto ready to drop right in for display purposes should I want.
Can't wait to get it next week _________________ Richard |
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Julian
Joined: 19 Apr 2010 Posts: 278 Location: Warrington
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Posted: Wed Apr 11, 2012 2:13 pm Post subject: Re: Converting Magneto ignition to coil ... |
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Rdover wrote: | My 'original' magneto has been rebuilt twice in 4 years and has failed twice.
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Hi, that's a pity as it obviously wasn't repaired my 'Magneto Man' on the Stationary Engine forum! He did one for me a few years back (repaired by new 'old stock' coil) and it's been 100% reliable.
To my mind there's absolutely no reason why a magneto should not be (practically) totally reliable. In a previous life I used to look after the things on light aircraft engines and almost always they would last the TBO of the engine - around 2000hrs. Just a regular points and timing check.
Julian. |
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Rdover
Joined: 26 Nov 2007 Posts: 413
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Posted: Wed Apr 11, 2012 2:21 pm Post subject: |
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To be fair to the guy who did the work I suspect he was starting from a point of inferiority - my mag is pants!
In any case the thing is at least 80 years old, battered and 'fonty' as we say in Glasgow (fonty: fon tae bits or falling tae bits)
Give me the name of your guy - it does no harm to have some redundancy/backup/spare capacity. _________________ Richard |
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Julian
Joined: 19 Apr 2010 Posts: 278 Location: Warrington
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Posted: Wed Apr 11, 2012 5:13 pm Post subject: |
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Rdover wrote: |
Give me the name of your guy - it does no harm to have some redundancy/backup/spare capacity. |
His name is Martin and he's from Wellinborough, he's actually a 'Technical Project Officer in Physics Research World' and magnetos are just a hobby. He is a real wiz, no question, he even started to tell me about the different characteristics of insulation porcelains in spark plugs! I strongly recommend him especially if you fancy an 1/2 hour phone chat about mags
If you go to http://www.stationary-engine.net/forum/ and search for Magneto Man you'll find him, that's what I had to do. I'm a little hesitant publishing contact details on the www as I'm not too sure if that's what he wants.
Julian. |
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Kelsham
Joined: 18 Jan 2009 Posts: 349 Location: Llandrindod Wells Powys
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Posted: Wed Apr 11, 2012 5:44 pm Post subject: |
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I find with my 1932 BSA three wheeler, that when I ran just using the battery without a dynamo, that the life of the battery was greatly reduced by the heavy discharge.
It is a six volt battery and usually only lasted two years before losing the ability to fully charge up.
Once I replaced the dynamo the life extended to five years.
Kels. |
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emmerson
Joined: 30 Sep 2008 Posts: 1268 Location: South East Wales
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Posted: Wed Apr 11, 2012 6:29 pm Post subject: |
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Rdover, may i suggest that you use a battery from a mobility scooter You can buy whats known as a 12x12 (12v x 12ah) for around £30. Herselfs scooter has two of these, which I replaced last year, only to find that the fault lay elsewhere. I now use the old batteries in my caravan, as their small makes them ideal for hiding away. They're also very safe, being gel rather than acid. |
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Rdover
Joined: 26 Nov 2007 Posts: 413
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Posted: Thu Apr 12, 2012 9:38 am Post subject: |
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Thanks folks.
I'm a keen 4x4 fiddler (Moderator on www.difflock.com) and I'm rather fussy about wiring up winches and using the correct connectors and cables.
I have links to a local Manbat distributor and after a wee chat yesterday they suggested exactly that - mobility scooter batteries. I was think of leisure rather than deep cycle as the draw will be smaller and consistent (like running a fridge, lights etc) rather than huge draw for short periods even though both need a battery that can survive frequent deep discharge.
Lucas, the Prince of Darkness as we Landy owners know them as, do batteries from 12Ah up to ~50Ah and I'm more limited by space and the need to take it out easily for overnight recharging .... just like mobility scooters.
The new lead-acid batteries are non spill and 30% cheaper than gel.
Thanks for all the tips and suggestions - just cos I think I know what I'm doing does not mean I'm not going to cock up! _________________ Richard |
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RotaryBri
Joined: 20 Dec 2007 Posts: 465 Location: Warwick
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Posted: Thu Apr 12, 2012 5:58 pm Post subject: |
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The 12v gel battery on my Victa motor mower lasted for 20 years and is used on some motorcycles as well. The replacement cost me £60 which is not expensive if it lasts as long. These Victa mowers seem to go on forever. _________________ Keep Torqueing,
RotaryBri
1976 NSU Ro80 |
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Julian
Joined: 19 Apr 2010 Posts: 278 Location: Warrington
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Posted: Thu Apr 12, 2012 7:06 pm Post subject: |
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RotaryBri wrote: | The 12v gel battery on my Victa motor mower lasted for 20 years and is used on some motorcycles as well. The replacement cost me £60 which is not expensive if it lasts as long. These Victa mowers seem to go on forever. |
That's good for an battery powered mower. You don't see many these days - many years ago I remember they were common, with basically a 12V lead acid 'car' type battery sitting on the deck. Now worries with slicing the cord
I'm not sure why a mower needs a gel battery it's isn't a normal requirement for a mower to be capable of working upside down
Julian. |
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Bitumen Boy
Joined: 26 Jan 2012 Posts: 1735 Location: Above the snow line in old Monmouthshire
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Posted: Thu Apr 12, 2012 9:30 pm Post subject: |
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Julian wrote: |
I'm not sure why a mower needs a gel battery it's isn't a normal requirement for a mower to be capable of working upside down
Julian. |
No, but you can let it down a steep - but smooth - bank on a length of rope, and thus mow grass you couldn't even stand up on. Damned hard work with a petrol mower and I doubt much easier with a battery, but certainly possible and probably the thinking behind using gel batteries. |
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Julian
Joined: 19 Apr 2010 Posts: 278 Location: Warrington
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Posted: Thu Apr 12, 2012 9:33 pm Post subject: |
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Bitumen Boy wrote: | Julian wrote: |
I'm not sure why a mower needs a gel battery it's isn't a normal requirement for a mower to be capable of working upside down
Julian. |
No, but you can let it down a steep - but smooth - bank on a length of rope, and thus mow grass you couldn't even stand up on. Damned hard work with a petrol mower and I doubt much easier with a battery, but certainly possible and probably the thinking behind using gel batteries. |
Ah yes, I was forgetting that. I've seen the council do that with Flymos!
Julian. |
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