Saving Old Seagulls

When an old Villiers coil goes open circuit, what choices are there in respect of replacement?
Searching past posts reveal that with a bit of effort an OMC coil (Sierra 18-5181) can probably be shoe horned in at a cost of $20 plus p+p. I am not keen on doing that.
Otherwise the choice seems to be £65 for the correct coil - the M1634E - newly manufactured and giving all the advantages of reliability and originality. Obviously the best choice, but at £65........

Another choice seems to be a newly manufactured shorter (by 0.5") coil - the M1361 - but how to reliably mount it. These M1361 seem to be available at £25 from motorcycle dealers or £45 from ignition specialists. Is it a matter of you get what you pay for in this instance? But, the issue of reliably mounting it has to be resolved. Has anybody done this? It seems to me that if the M1361 can be reliable mounted then that is a viable choice. What views?

This coil replacement problem is just going to get more significant with time. Coils will continue to go open circuit. As for their owners...... how long does anything last for?!

Jeremy

I don't think £65 is that bad in this day and age. It buys the correct part made to modern standards, which I suspect will last for a lot longer than the original.

Many of the originals have lasted 50+ years, I don't think I'd take that bet!

Yes, Adrian, I don't disagree, and as I have said it gives all the advantages of reliability and originality, but I am always looking for something cheaper and better! Yes, it will probably lasting longer than the 60+ years of the originals, But will FV2306 still being used in 10 or 20, let alone 60 years time?
I have previously bought a couple of these at £65, and will probably buy another, but want to consider any viable alternative first.
Jeremy

A set of decent make up collars could easily be made to allow the smaller coil to be fitted. Anybody with a lathe would be able to make a pair.

Incidentally I wonder what a FV would cost in today's money?

Remember this clip on putting a smaller coil into a JM Magneto

https://youtu.be/a0k5tFWHEtc

For anyone planning on buying a JM/coolie hat coil DONT buy one of the £65 ones!
When i bought one all i go was a MK1 flattop coil with some space ring thing on both ends!
I strongly suggest you do what Hugo shows in his video.

Jacob

Do you have the core size (length/diameter) of this suggested coil, & is the HT output in a suitable location, what style of motor is this coil built for, Jeremy?

I do not think that it is just a matter of making up the half inch difference in length with a couple of quarter inch spacers. The clamping screws are very marginal in respect of gripping the pole piece at both ends. Would the length of engagement of the pole piece into the cast end cheeks be significant in respect of performance? Incidently, on one coil that I was examining the pole piece, surprisingly, was of a laminated construction.

Cost of an FV today? I have really no idea! Probably the same as a small modern outboard.

Jeremy

Charles,
The core dia is 7/16. The core length is 87.4mm (compared to the possible replacement of 74mm. The HT take of is in the correct position compared to the original ie mid way along the coil. I do not know for sure the usual usage, but probably motorcycle.


Adrian, Would the 1/4 spacers at each end of the coil need to be non-ferrous?

Hugz, Thanks for the youtube info. Food for thought. But the small difference in length would not permit the use of 'extensions' in that way.

Jeremy

If I'm right Jeremy the core of the smaller coils just fits into the cheeks but not enough to secure which, as you say, would render my adaption inoperable.

Hugz,
Yes, but I think that I can locate them. With the proper length pole the 2 BA clamping screws in the cheeks, locate on the o/d of the pole piece inside the cheeks. I think that there is just enough length with these shorter coils to file a 1mm depth groove in the end faces of the pole pieces - at the right angle with respect to the HT output - so that longer 2BA screws will locate in this groove. This should locate the coil rotationally as well as axially.
The spacers that Adrian mentioned would also give extra security for axial location. I guess these should be plastic or brass to avoid changing the flux path - but I do not understand that technology.
However will the shorter engagement of the pole piece in the cheeks reduce the coil performance?

Jeremy

I have done this is the past with smaller coils, they don't move about as I added iron bushes and they just hold on to the grub screws, rotation could be an issue, but never found it to be a problem and they will not fall out.

Gannet wrote:Hugz, However will the shorter engagement of the pole piece in the cheeks reduce the coil performance? Jeremy

I'm a little confused of the induction properties of cores and cheeks, I note the Wipac has a laminated core in the shape of W. The two tips of the W has magnetic pickups whilst the coil is is in situ on the central spike. A different configuration to the Villiers.

I've hoping Peter of 40TPI can shed a little light on this subject. He is our resident expert.