Classic cars forum & vehicle restoration.

[Rdover]

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.
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Richard

[ukdave2002]

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

[Rdover]

[Rdover]

[Rdover]

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
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Richard

[Julian]

[Rdover]

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.
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Richard

[Julian]

[Kelsham]

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.

[emmerson]

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.

[Rdover]

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!
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Richard

[RotaryBri]

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.
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Keep Torqueing,

RotaryBri

1976 NSU Ro80

[Julian]

[Bitumen Boy]

[Julian]