how to check a villiers coil?

[Geoff Uphill]

It would seem I can test a villiers coil with a multimeter.
I have quite a few - the best two are off the baseplates, but have their triangular end lugs attached and are connected to to a points unit, complete. One is on a baseplate - but no points unit attached.
I'm wanting to make up a new villiers baseplate unit - but want to test them out if possible first so as not to use a dud one.

I've read various posts which are just confusing me really. On none of them I am getting anything between the plug lead terminal ( where the ht lead presses against ) and the end lugs ( which I presume are baseplate/earth )
I do get something between the small wire going to the points box - and the end lugs. But this is not what I'm reading I should be getting.
I'm sure I'm doing something wrong.
I have the meter on Ohms, have tried it on the 200, 2000, 20K etc.
Can someone explain 'very simply' what I should be getting between what - or what might be causing a strange reading ?
They all all pretty good looking coils - ie, not swollen up or distorted.
Geoff - Bristol.

[billyboy]

do you have early villiers(3 cutouts in flywheel) or late villiers(2 cutouts)?

[Geoff Uphill]

Standard Mk I, Villiers - three holes in flywheel ( page 6 Seagull spares book )
I don't know what you mean by 'late villiers with two holes in the flywheel'? That, to me, is Wipac (Mk 2) ignition. But what I'm asking would apply to that system as its basically the same thing.

I've put a new battery in the multimeter - and have been playing with many bits !

All my Wipac coils give me an Ohm reading between the plug lead pickup - and the points wire terminal or end lugs (none of them are on their baseplates )
What's odd is that 'every' Wipac coil I have tests good ( two are 'brand new, unused ) - but 'every' Villiers coil I have seems to be dud ! Maybe its just sods law.

It was confusing me that I get continuity between the points wire terminal - and - the coil mounting lugs - but I suppose that figures to make a circuit around from coil to points to baseplate and back to coil - to be broken by a points gap? ( I still can't get my head around this despite reading up on how coils work )

An unused, new, Wipac coil unit ( mk 2 , on its baseplate, gives me the following -
2K ohms approx between Plug Terminal - and - baseplate/coil mounting lugs/wire to points terminal screw( even with the points gap insulated ) ie, even with the gap open, the coil side of the points is continuous to the baseplate.

So I would expect a villiers coil, unmounted, no points box to give similar readings. All mine are showing continuity between the points wire solder terminal and the end lugs - but nothing between Plug terminal and points wire, or end lugs, or baseplate, when mounted. Apparently all dud ! Which is a pain as I have loads of villiers flywheels and but no Wipac.

I could mount one up on a temp crankcase shell, stick a flywheel on and ht lead, spin it up and see if its sparking - but my concern is that its just jumping a break and its going to fail pretty quickly. I've just sorted out crankcases to give a match between Flywheel/ignition types and serial nos - which I prefer, so getting a Wipac flywheel to go with my wipac bits messes all that up.
Its a lot cheaper though than buying a new villiers coil ( I see villiers parts site list them at £48.00)

But I still find it hard to believe every one I have is dud !

Geoff - Bristol
ps - my summer cruise of last year in Lena from Uphill to Milford, Skomer and Solva is on Youtube. Hopefully, this season, I'll do some footage of of my Silver Century aux pushing her along .http://www.youtube.com/watch?v=Eg_uK2Tw ... re=channel - part 1 of 5.( needed editing down a bit but was too much fuss )

[chris]

I prefer the villiers to wipac, but if a wipac is set up and working properly it is a good system.
Would spinning them up with the drill trick undud them?

[Geoff Uphill]

I prefer the villiers to wipac, but if a wipac is set up and working properly it is a good system.
Would spinning them up with the drill trick undud them?

Chris - Ithink I pefer the Wipac myself, but as I said, its nice to keep the ignition matched to serial no.
I've found some wiring diagrams which have helped a bit ( links below ) - but I think if there is 'no connection' showing up between the HT lead and its ground point, then it must be a bit suspect. I gather the secondary winding is very fine wire, so a tiny break would do in the multimeter - but the HT spark current would get over it maybe. These may actually work OK - but they do not give a resistance reading.

I think the spinning up is more to do with the state of the magnets creating current for the primary coil. Maybe I'll set one up on a crankcase and see what I get, but I still wouldn't trust it somehow.
The diagrams I have found show both primary and secondary windings jointly earthed to ground - and make things a bit clearer on the primary circuit.
http://www.geoffrichings.co.uk/images/coil-cutaway.gif and http://www.geoffrichings.co.uk/images/coil-primary.gif

The forty + I'm rebuilding actually has nicer crankcase on the 1974, Bing carb GFP - rather than the SJP crankcase - so can do it with a Wipac unit. They both were aquired without any ignition assemblies.

If anyone has any Wipac Flywheels going spare I aquired recently a huge pile of spares, new and old. Just never seem to have what I really need, so could do a swap for something.

[pistnbroke]

I thought we had established that some of the coils incorperated a spark gap in the HT winding ...so your multimeter will not show a reading.....try this .....connect a plug to the plug lead ...earthed of course and then connect 12v AC from a transformer via a 21w indicator bulb to the primary .......that should give you HT output if the coil is ok..

[billyboy]

HT lead disc to coil end.......................................3.75 ohms
HT lead disc to wire going to contact point................ 3.75 ohms
coil end to wire going to contact point......................0.5 ohms
coil end to coil end.............................................0.1 ohms

these are from a manual i have and are as yet untried by me. may be of some help.they are different to the mark II however.they dont have to be exact just somewhere in the ball park. cheers

[Collector Inspector]

Get yourself an anologue multi meter..........not digital as they do not do a proper test.


Then watch this!

http://www.youtube.com/user/alectraproj ... T8rk5QWgS0


Can Not go wrong

B

[rosbullterier]

Excellent film.

[Geoff Uphill]

Thanks all - all very useful. Very nice vid - Youtube comes into its own for stuff this obscure !

Maybe will pick up an analoge meter - but the digital was showing something about right on the good wipacs - looking at those specs for ohm readings - but nothing on all the villiers. I did notice that the digital would not show a constant reading - it would read, then go to nothing, until one re-made the contact again.

I'm surprised it was not mentioned in this vid, that some have 'designed' spark gaps and will not test out with a meter - is this really the case ?

Also - I don't quite follow the 12v test.

If I fix coil to baseplate, fit HT lead and plug and earth plug to baseplate. Then 12v neg to baseplate - 12v pos to primary wire to points, with bulb inline.That energises the primary coil and the light shows its good. Have i got that right ? What then - surely the plug will only spark when that circuit is broken ?

sorry - edit, - I see you said '12v AC' - did you mean AC as opposed to DC. If so, I have no source of 12vAC.

Geoff

[philj]

Hi Geoff,
just took my century apart to check,
points and condensor disconnected, using a fluke DVM,
points wire to ground 0.7 ohms
HT tag to ground 4.7k ohms
Got to put it back together now! Hope that helps.
Have been missing your Lena updates for a while, thought you had given up!
I also have an invader 22! Have been out in a F7 with 8.2 knots speed over ground, without a reef, very good safe boats!
Will try to forward a pic to you site.
best regards,
Philj

[Geoff Uphill]

Hi Geoff,
just took my century apart to check,
points and condensor disconnected, using a fluke DVM,
points wire to ground 0.7 ohms
HT tag to ground 4.7k ohms
Got to put it back together now! Hope that helps.
Have been missing your Lena updates for a while, thought you had given up!
I also have an invader 22! Have been out in a F7 with 8.2 knots speed over ground, without a reef, very good safe boats!
Will try to forward a pic to you site.
best regards,
Philj

Hi Philj -
didn't do much tail end of last season for various reasons - but we had a great cruise to to Solva( see the Youtube link in my first post - or there is a link on the site now) Hopefully down tomorrow to sort her out on the river - and maybe off to Milford H over the bank holiday. Yes, as you say they are very stiff in heavy seas, not so quick in light airs, but the tides usually get me there - reassuring in the Bristol Channel.
I think these villiers coils are suspect - I've got a small anologue meter now and still no reading across the secondary. Shame. as I have loads of villiers baseplates and flywheels.
Hoping to get more vids this season - and will do one of the seagull Silver C I have on the rail pushing her along. I get 4 kts no problem even without full throttle. I tie the tiller to the pulpit stancion and she steers fine with the tiller - and have a fixed transom mount, so it just hooks in and set the pin. I made a similar mount from a few bits of old stainless bits, so it sits on the rail with the same pin and clip.
e-mail me a pic and with any info you want - thanks - Geoff

[40TPI]

I thought we had established that some of the coils incorperated a spark gap in the HT winding ...

That is incorrect. Please see my earlier posts on coil structure, plus those of H-A.

The Villers coils are auto transformer configuration, ie the primary and secondary windings are in series. One end of the primary is connected to chassis. The common connection between the other end of the primary winding and start of the secondary winding is connected to the points. The end of the secondary winding is connected to the spark plug.

An indicated 4.7k Ohms secondary resistance on a Villiers Mk1 coil ( using a decent Fluke) suggests it has internal rot in the secondary winding. From post mortems on Villiers coils in the last six months I'd say it was fine for phootling about on the river but would not rely on it where safety was involved. An indicated 0.7 Ohm for the primary is actually being swamped by the meter leads and contact resistances in making the test connection. A Villiers Mk 1 primary coil resistance is typically 0.3 Ohms and can not be accurately measured with a hand held DVM two wire resistance test. That said you can tell if it is still there although the primary is highly unlikely to have failed before the secondary!

Peter

[Geoff Uphill]

Peter - useful info, thanks -

So what reading would you expect from a new villiers type unit - or for that matter from a Wipac in perfect order ?

Using a 'very basic' analogue meter - on a Wipac ( apparently unused, as new ) I'm getting a 'very small' reading from the primary.
maybe 0.2. The secondary was giving me 4.7 K. Are Wipac specs different to Villiers?

I've just tested the other four used Wipacs I have and they are all between 4.25K and 4.7K . If they do vary, is 'higher the better' ?

At last its now clear in my head how these things are wound and connected internally.

ps - edit - I've just checked all those past posts. Facinating stuff ! - I found the info on the new villiers at 4k ohms secondary.
I'm coming to the conclusion that Villiers coils were cunningly made in a way that meant they just kept sparking even if they were broken. If they test out with some voltage across them and have a healthy spark I have a little more faith in them to keep going now.
It seems the innards of the Villiers coil is more mysterious than that of many an Egyptian mummy

Geoff

[40TPI]

So what reading would you expect from a new villiers type unit - or for that matter from a Wipac in perfect order ?

Sorry, I'm afraid I do not yet have definitive information on WIPAC units.

If you don't do anorak stop reading now.........this is glaze over material.


When talking about "new" Villiers coils there is the possibility for misunderstanding. Somewhere there may well be 40 year old shelf stocks of unused Villiers type M1634 coils, as fitted to Model 102 motors. Having dismantled several examples of this type of coil, turn by turn of wire , I've come to the conclusion that all examples of these coils are slowly deteriorating through chemical corrosion of the coper wire in the secondary winding. Fifty years on this unfortunately also applies to any NOS "New Old Stock" on the shelf units just as much as units already fitted to motors.

Storage temperature, temperature cycling , humidity, salt and other chemical contamination, atmospheric pressure changes and a host of other factors including the factory conditions on the day of manufacture along with the cleanliness of the assemblers fingers will likely affect the actual "life expectancy". The coil can look perfect externally but be rotten to the core inside. This is probably not welcome news.

What this means is that unless we can find some Villiers product spec sheet listing the original resistance values we can not be certain what they measured as they left the production line. It also follows that if there is age related deterioration there is no accurate secondary resistance value that we can quote as a go-no go value in 2010. I have been collecting resistance data from anybody I can and there is a wide spread of values. Much too wide to be explained by manufacturing tolerances.

( Villiers operatives never managed to wind exactly the same number of turns on successive layers; but managed to roughly get the total number , coil to coil, the same. Since the length of wire used, and hence resistance , is directly proportional to turns diameters any variation in layer winding numbers will cause the production resistances values to spread. ) At the moment I'm calculating projected values about five hundred Ohms lower than what I'm measuring and receiving as reports. The effect of wire diameter reduction due to variations in winding machine tensioning or spooling from bulk reels on the production line have not been quantified but will not account for the total spread of a couple of thousand Ohms. My current view is that if you record an actual resistance of greater than 2.8 or 3k on your genuine type M1634 coil it is heading south. If it is open circuit it has failed even if it is still producing sparks. How long it will continue to produce them is down to the gods.

And this is where the confusion on "new" Villiers coils can creep in. There are several sources on the www of what are termed OEM replacements, compatible, etc etc "Villiers" coils. These have been manufactured recently somewhere in the world; most likely in China. Others are exchange rewinds of Villiers units. I have not dismantled any of these but it is a certain bet that they have not used the paper, cloth and shellac construction of the original Villiers coils. I'd expect them to be using modern materials such as Mylar and epoxy. There is also no reason for them to have used the exact same number of turns, wire size etc etc as the original design. This means that any secondary resistance value quoted for these coils has no direct relationship to what a good M1634 coil was in 1951 or is now in 2010.

Some care is needed when using the term "new" when applied to Villiers coils to ensure apples are compared with apples!

Peter