Spark plug alternatives

[Rudy from Norway]

I’m planning ahead for the ignition system for my ongoing Farm Boy hit’n miss engine build (have a thread on it). The first option I came across was the Rimfire. This one is rather expensive and will be even twice that shipped to Norway. And it seems to be available in just the long version? Locally I can buy OS spark plugs for 1/4 the price. By the marking on it (1/4-32) I assume that is the threading, the same as the Rimfire? Right?
Anybody having used the OS plug on a cold running engine as a hit’n miss?

Rudy

 

[TonyM]

I bought a couple of these on amazon. Wish I had got more as they were two for price of one. A week later the price was back to normal. They work OK on my engine.

 

[Cogsy]

I've never purchased a plug, instead I make my own, purely for economic reasons. So far they've been perfectly fine in hit and miss engines and in my Rupnow Vertical, though I'm yet to use them in a high speed application. They're not overly difficult to make if you want to try your hand at it.

 

[cwelkie]

For what it's worth, I'd second Al's suggestion to make your own. If you can build a Farm Boy, a spark plug will be no more difficult than a fuel mixer/carb. Attention to detail and taking your time. Besides, there solid bragging rights from saying, "Yes, I made the spark plug too."
Charlie

 

[Rudy from Norway]

I like the "I even made the spark plug" thing. I will give it a go. However, to minimize problems from the start I did order a Rimfire along with the PIC buzz coil driver from Jerry Howel. I have confidence in that multiple spark idea. Since this will be my first IC engine (second build ever). I will get it running and then take a step back and do the ignition. I'm also obligated to do the electronics; after all, that's my trade.

Rudy

 

[deverett]

Probably too late for you now, but a nearer source of ignition equipment is in the UK. Have a look at Minimag, who are also the local agents for Rimfire plugs - among other things.
http://minimagneto.co.uk/Products.php

Dave
The Emerald Isle

 

[Rudy from Norway]

Thanks anyway for the info Dave. I will need more ignition component in the future..

Rudy

 

[TonyM]

I have built several of these ignition modules by John Gedde. http://www.homemodelenginemachinist.com/showthread.php?t=20415&page=5
Several simply because it was cheaper to buy multiple components.
I have them set up with 12V cells because I had them lying around. With hall sensor and plug cap coils they work out around 20GBP each per set up. Apart from a bad joint which was obviously my fault they all perform perfectly.