Team-BHP - Magneto blues? Get all your magneto info here...

A magneto is an ignition device used on many of the pre 1950 cars and motorcycles ,and one of the most misunderstood devices due to which many a car or motorcycle has gone to its grave.

I will be glad to answer any questions that members may have to have a better understanding of this piece of equipment so as to get their magneto problems sorted out.

I have restored over hundreds of magnetos for restores from all over the country.

Quote:

Originally Posted by magneto (Post 1284476)

That sounds familiar. Were you at the Cartier Show by any chance ?

Without going further OT - please see DKG's mention of you(?) in post #32 onwards here - http://www.team-bhp.com/forum/vintag...ml#post1041201
I guess this is what wasif is referring to?

Now, back to the topic :

Heres a breif article i remember reading the first time i ever heard of a magneto - HowStuffWorks "How does a magneto work?"

Magneto, do start us off with some basics. Perhaps, various types? Expected mantainence? Most common problems faced?

Thanks,
R

The link provided , provides a good insight to the workings of magnetos.
I would start of with the type of mags i have encountered , and the most common problems encountered and the rectification of these.
As far as the types goes , we can divide them into two basic types the rotating magnet type and the fixed magnet type .
I will try to explain the basics of the first type , the rotating magnet type such as the SR , used on late 1950 motorcycles and the Norris mags used on BMW motorcycles , and other assorted makes used in marine and aircraft engines.
These type of mags are fairly simple with a rotating magnet and a stationary coil wound on a soft iron core .
There is a cam attached to the rear end of the driven shaft and this in turn operates a point which is timed to open exactly when the magnetic flux is at its maximum.
The opening of the point at the maximum flux level causes the primary winding of the coil to collapse causing a electrical pulse which in turn energizes the secondary coil , due to which an arc is generated across the plug gap.
Now let us what sort of problems one can encounter with these mags ;
1) Coil failure.
2) Condenser failure .
3) Change in timing caused due to the wear on the leading edge of the cam.

4) Weakening of the magnet due to age and misuse .

5) Weakening of the HT insulation .
6) Worn out points.
Rectification of the above will be dealt with on the next reply.

Allow me remind you Dad (Magneto), that you've restored a pretty amount of magneto's internationally, not just within the country.

I assume that there are still people restoring these components with traditional methods all across the globe, which give the magneto a shorter shelf life and higher risk of failure than if they were to switch over to more technologically sophisticated materials and methods.

People need to realise that cars and bikes from the golden eras of motoring should not be restricted to old ways of fixing them too! Lets use the 21st century to bring back the beauties from the days of our grandparents!

Nice observation Dj , reliability is an important factor , as traffic conditions have changed over the years and one has to keep up with the more efficient vehicles on the road , so it is necessary to make small improvement , for example in better braking liners , hardened valves and valve seats to take care of the unleaded petrol ,and a better and hotter spark on the plug with the help of better ignition devices , like cdi on alternator models and a more efficient mag using modern internals to increase the output.

Hello Magneto, welcome.

Just want to add my bits for owners of Magneto driven cars and bikes in India.
Magneto is one of the best in the country, is there any other? In the old days, till about 1985 there was a Lalloo Magnetowalla at Opera house. Dinesh was his name, a nice gent who unfortunately is no more. Lucas also used to repair them, and one day they just threw out all their equipment. Magneto, being an engineer approached this with an engineering mind and his magnetos run. I am glad that this is not problem for us. There are certainly others, but their magnetos often come to Magneto for reworking.
This is a tip for the needy, please take note of this post in this context.

harit

Welcome aboard sir.

I'd like to narrate a little incident, perhaps now 4-5 years old. I had recently bought my 56 Triumph Tiger 100, and sparking was an issue. I was told to contact Mr. Magneto himself. He was gracious enough to entertain me in his house from 8pm to 11pm (he was leaving for out of town early next morning) while he changed the capacitor and pick-ups for my Lucas K2F magneto. He worked meticulously, told me great stories, showed me his Healey (prior to restoration), and even showed me his Tiger, BMC 933 (mine is BMC 935). What a coincidence.

Quote:

Originally Posted by djhealey (Post 1286196)

Hi Mr. Magneto,

I like the name you have chosen for the topic. I know of someone inthe US who used a similar one for a description on the R50 magneto.

Do you also repair mags for international customers?
What is the traditional method and the newer one? and the major differences between them.
You once mentioned an Old Gentleman in France who was an expert in magnetos. Is he still into repairing magnetos.

Regards
Nigel.
P.S R50 magnet remagnetised by you

Thanks Nigel, I do remember having done your magneto couple of years back.
I would love to do jobs for international customers, as i found out on my recent trip to Germany, that it is prohibitively expensive to do a similar job in most countries, so they could take advantage of the skills that are still present India.
When i talk about modern methods, i could give you a brief comparison of the old and new methods and materials.
One has to take into account that most of the magnetos which need rework are in a very poor condition on account of the number of times it has been repaired over the years.
The material originally used in the coil was of organic nature like the insulation was made from natural resins which is either slightly acidic or alkaline, resulting in a reaction with the copper wire which either corroded the fine wire or caused a leakage in the insulation resulting in weakening the output of the coil.
The insulation used nowadays is synthetic in nature with a neutral Ph, based on a acrylic compound.
The inter layer insulation between the layers was a fine woven natural silk cloth, whereas polyester is a better choice .
By the way in the older repaired magnetos done by Mr Lalu Magnetwala, butter paper was used making it susceptible to rotting and absorption of moisture resulting in arcing which burnt the coil.
The other important difference is in the data of the turns used in the winding.
The rule of thumb is to have a ratio of 1 is to 100 between the primary and secondary winding ,but in practice it is difficult to do so because it is difficult to fit in the turns into the limited window area, so normally a ratio of 1 is to 60 was used.
With a thinner and more efficient insulation used, a ratio of 1 is to 80 can be achieved.
These above factors do help in making a magneto much more efficient then the original design.

Hi Nigel, sorry i did not answer you question about the French gentleman, Mr Michel DeThomasson, mdethomasson@wanadoo.fr, who is a world authority on magnetos and had come to India to judge the motorcycles for a VCCCI rally and was surprised to see all the magnetos on the cars and motorcycles working perfectly, on asking around as to who was responsible for this, someone pointed towards me and this was around 11 Pm in the evening.
After that we had a long talk almost till 12.30 Am, He was very happy that he could meet a person like me in India, in which he considered there was no one capable of caring out repairs almost up to his standards.
He consequently made an offer to me to take up his jobs in SE Asia, but due to some difficulty with the custom rules pertaining to import for repairs, i missed out on that opportunity.
Museums all over the world consult him for their problems pertaining to magnetos.