Wanted Champion V3 spark plugs?

[mole42]

The engine I'm building specifies Champion V3 spark plugs - 14mm thread, 5/8" (16mm) spanner size, 7/16" reach - of course, they are made of pure unobtainium these days. Can anyone suggest an equivalent?

On the other hand, I've seen articles that describe making spark plugs in the DIY workshop but I'm not convinced that the plastic insulator will survive. Is there a tested design anywhere?

Thanks!

 

[stevehuckss396]

The Champion V-3 was the smallest size plug using a smaller base, but still utilizing the 1/4”- 32 thread size with a shorter 1/8” thread depth. Wrench size 5/16”
http://www.antiquemodeler.org/sam_new/p_engines/assets/Charlie Reich on Champion Spark Plugs.pdf


1/4-32 is a common model engine plug. any modern 1/4-32 would most likely work. You would need to check the thread length to be sure they wont hit the piston. Most have a thread length of about 1/4 inch. The plug would need a thick washer to compensate for the long thread to keep iy from going in too deep.

If you would rather not make one or some look here.
http://www.miniaturesparkplugs.com

 

[mole42]

Hmmm. I just looked at the Rimfire V3 - $35 each! Makes it rather expensive since I need nine of them, so I'll be making the spark plugs too.

 

[stevehuckss396]

Look at miniaturesparkplugs.com

$12 bucks

Also will have new surface discharge plugs coming out for $15

 

[bluejets]

Or .....

7.8US $ |Rcexl 1/4 32 ME8 ME 8 /ME8 Iridium Spark Plug for RC JBA NGH Gasoline Engine|Parts & Accessories| - AliExpress

 

[awake]

Would the CM6 plugs work? 10mm thread size. Amazon has them in packs of 4 or 6 for around $6 each:

https://www.amazon.com/5812-CM6-CM-6-Spark-Plugs/dp/B019P3BQY6

 

[johwen]

Hi Member 42,
I make my own 1/4 inch thread 5/16 hex BMS. Insulators purchase 4mm ceramic tube with 2mm bore and cut to length usually around 1inch long. You need a diamond blade to cut. I make my centre electrode with spark end with surface ignition. I Loctite the insulator in the plug body using High temp High strength Loctite and same for the centre electrode adjust the spark gap to around .020" before Loctite sets. Easy to make look scale and work well. One Hit and miss engine now 10 years old, still runs well on original plug and is easy to clean. Never had the Loctite let go. Cheers John

 

[Majormallock]

Hi Member 42,
I make my own 1/4 inch thread 5/16 hex BMS. Insulators purchase 4mm ceramic tube with 2mm bore and cut to length usually around 1inch long. You need a diamond blade to cut. I make my centre electrode with spark end with surface ignition. I Loctite the insulator in the plug body using High temp High strength Loctite and same for the centre electrode adjust the spark gap to around .020" before Loctite sets. Easy to make look scale and work well. One Hit and miss engine now 10 years old, still runs well on original plug and is easy to clean. Never had the Loctite let go. Cheers John

Hi, John, would this method work for glow plugs as well. I like the idea of building my own and I need 5!

 

[johwen]

Hi, John, would this method work for glow plugs as well. I like the idea of building my own and I need 5!

I've never tried making Glow plugs but I don't see why they couldn't be made however, the filament would be a bit of a challenge. John

 

[Bazzer]

Hi, John, would this method work for glow plugs as well. I like the idea of building my own and I need 5!

Making glow plugs is much easier than spark plugs, the big difference being that the electrical insulation requirements at 2V is much less demanding than say the 10Kv of a spark plug.

I am making a batch of 5 glow plugs as a trial for high performance model aircraft engines, I will post some pictures next week of the progress.

 

[Jasonb]

My first port of call is The Green Sparkplug Co, they show 26 options for a 14mm plug with 7/16" reach By Champion, 79 if you are not worried about the maker. If the sizes you give for the V3 are correct

https://www.gsparkplug.com/ignition/spark-plugs/14mm-diameter?manufacturer=92&reach=55559
if you do want to make then then ceramic "fish spine" wire insulation works as does glass tube, I've used the later

 

[Majormallock]

Making glow plugs is much easier than spark plugs, the big difference being that the electrical insulation requirements at 2V is much less demanding than say the 10Kv of a spark plug.

I am making a batch of 5 glow plugs as a trial for high performance model aircraft engines, I will post some pictures next week of the progress.

Thats great. What will you use as filament?

 

[Bazzer]

Thats great. What will you use as filament?

I have obtained the correct wire as used by commercial glowplug manufacturers, I have the first plug bodies assembled, just got to spot weld the wire into place.

B.

 

[L98fiero]

Thats great. What will you use as filament?

I've not made one but nichrome or Kanthal resistance alloys should work though there probably are specific alloys for the application.

 

[Bazzer]

Principally methanol fuelled model engines have a platinum element but it is alloyed with Rhodium and I think Iridium, the wire is very expensive now with the pressures on these materials from automotive among other things.

 

[Jasonb]

I saw a video the other day of someone showing the Platinum alloy element from a pair of hair tongs relighting the gas after it had been turned off, quite effective. He was hoping to use it to stop the pilot flame going out on a flame ignition engine.

 

[petertha]

I am making a batch of 5 glow plugs as a trial for high performance model aircraft engines, I will post some pictures next week of the progress.

Wow, I'm impressed. For sure looking forward to the pics & process.

 

[L98fiero]

Principally methanol fuelled model engines have a platinum element but it is alloyed with Rhodium and I think Iridium, the wire is very expensive now with the pressures on these materials from automotive among other things.

Hmm, maybe that's what they're doing when they 'borrow' a catalytic convertor, sounds like a similar combination of metals.