OMC coil on Villiers core

[phil]

Someone just posted on AOMCI Dockside about using an OMC universal coil on a Villiers core, they are getting good spark but have not run the motor yet. Could be interesting!

[Charles uk]

Which diameter core 7/16" or 9/16"?

[phil]

It was an SJP if I recall, in any case the OMC universal coil fits on a 7/16" sq. core. He commented that it slipped right on. Sierra 18-5181. Or OMC 0584477

[phil]

I've got a dead Villiers coil on a stripped down stator plate, I think I'll give it a try.

[cajuncook1]

Has anyone ever converted a Seagull's Villiers ignition system to using a OMC coil?  Well, I think I have. 

Story:  Got a 1964 Forty plus Seagull with Villiers ignition.  The coil was giving spark at first then went kaput!!  So, I got a ignition plate with coil,points, and condenser on ebay from the UK.  Seller stated he tested the ignition system and stated that it worked and was good to go.  Great!!  Well, got the ignition plate and I tested the coil. The primary windings buried the needle but the secondary windings had no resistance/continuity, bad coil. :-[

So, I worked things out with the seller to both our satisfaction, but I still needed a coil. Getting a new Villiers MK 1 coil is expensive and shipping here to the US is very expensive as well. I have read where others have adapted a OMC coil to fit old pre war Johnson motor and post war Wico Scott Atwaters ignition systems with success, so I decided to see if it would work with the Villiers ignition.


At first, I thought I would have to make a bridge laminate to allow the OMC coil to fit.  I was going to connect it to the left and right wing laminates.  I took apart one of the old coils to measure the cylinder type bridge laminate inside the coil.  I then realized that the circumference of metal cylinder laminate was perfect for sliding an OMC coil on.  So, I didn't have to make an adapter.


Here are some pictures.  I will post more when I have time, but I get a nice bright blue spark!!!  I got the OMC coil off a parts motor.     It cleared everything well under the flywheel!! 

The green primary winding wire went to the points and condenser.  The black ground wire was grounded to the coil wing laminate just like on the OMC ignition.  The coil's spark plug spike pointed out of the ignition plate hole where the spark plug wire normally connects to the high tension plug wire.

I tell you all this was not easy at first because the the back left and right wing laminate screws had to be drilled out because they were stuck and corroded.  I had to use a 1/8 drill bit and then work up to a 5/32 bit and oil to slowly get them out.  If it were not for that then the process would have been a lot easier.  I placed brass #10 24count by 2 inch length screws from the top of both left and right wing laminates to replaced the drilled out screws and use the brass screw in the laminate for a coil ground connection.  They were secured with a brass nut at the bottom of the ignition plate.  Just like the studs securing the left and right laminate wings. I used the front original original wing laminate studs to keep the laminates in there true position.


See the green oxidation inside the coil!

















The coil clears the movement of the flywheel and the flywheel's built in cam.






I believe the OMC condenser values are .18 - .22 mfd

If I am not mistaken, Phil posted the Villiers MK1 condenser values are .20 -.26 mfd

So, I believe the OMC coil should give good performance.

 


Well, I a get strong flat blue spark!!!  This work in progress and will update as I perfect this modification.

Thanks for following along and let me know what you think or any suggestions you may have.

David

[Charles uk]

Is there room to get 2 of those coils on there?

[cajuncook1]

I only tried the one coil and it snuggly fit in the depression where the high tension spark plug wire makes contact with the coil in the original set up. I don't think two coils would work unless some modification to ignition plate was done.

David

[Horsley-Anarak]

That looks like a good solution.

My only concern would be the screw in HT lead.

I would be much happier soldering the HT lead to the coil outlet.

All we need now is a cheap supply of OMC coils, I bought my last 4 from Texas.

H-A

[Michael]

HA,
What is concern about screw in HT lead? I actually prefer this, along with the rubber boot to keep water out. Much easier to replace HT lead when all you need to do is unscrew it. Soldering always worries me from the point of view of melting the fine wire in the secondary windings from the heat.

[Horsley-Anarak]

On the OMC engines that I have, the HT leads are clamped to stop them from moving.

With a Seagull the lead would be hanging loose, not even going through a grommet like the white CDis that have screw in leads.

If the lead has no positive location other than a short screw into the copper core, I personally feel it could be a weakness.

H-A

[Michael]

HA,
Ok I see what you mean, but as Seagull ignition plates do not rotate like an OMC plate, this should not be too big of an issue. Plus one could adapt a OMC clamp to the Villiers base plate as extra security.

[phil]

Most of the new Prufex coils that I've seen, the high tension lead pin in the coil is threaded and it takes a fair bit of effort to push the spark plug lead into it as you twist it on. Then there is always good old RTV sealant.

If it works it is a good solution at least on this side, as we can get the coils for $20-25 ea incl shipping from the U.S.and less if we buy 6-8 at a time. If you work on any 50-60s OMC motors you will use them up suprisingly quickly.

I'm not sure how much of price advantage it would be for those in the UK, shipping makes the Villiers coils very expensive for us, close to $100 ea by the time they get over here.

An AOMCI club member has about the best prices as well as volume discounts. He also carries Phelon(Repco) and Bendix (Scintilla) coils at a reasonable price.

He advertises on AOMCI webvertize from time to time.

[Charles uk]

Phil are the Prufrex coils the same as the green ones in the picture & what's the overall width ignoring the core of the green type ones?

A twin spark head might well solve a problem I have.

[phil]

Yes, the pale green ones are the Prufex coils. I measured 2 they are between 29-30mm in width and 44.5 mm in diameter.

People in the club have adapted them to many different cores, of course they will slip right on a 7/16" sq. core, but people have successfully cut larger cores down, to fit the coils. There was one where they used 2 coils side by side to fire a 2 cylinder motor, if I remember it was one that fired both cylinders at once.

Charles if you feel it's appropriate I could put up oldoutboardjim's email. He is the person I mentioned earlier, he appears to be willing to email a price list.

[phil]

So for anyone who is interested here the email I mentioned in the previous post: oldoutboardjim@hotmail.com