Model Boat Mayhem

Mess Deck: General Section => Chit-Chat => Topic started by: geoff p on July 20, 2012, 02:34:38 pm

Title: HobbyKing CDI ignition system
Post by: geoff p on July 20, 2012, 02:34:38 pm

Have any of you used or had experience of the "HobbyKing CDI ignition system" for gas-engines?

I've just bought one to use on a home-made, own-design stationary engine and wish to know:
a/ is it -ve ground?
b/ does it need a resistor in the spark plug?  I want to try my own, home-made plug before going over to a commercial CM 6.
c/ how much current should it draw from say, a 4.8V battery?  Useful for fault-finding.

HobbyKing Support state that it is just a plug-n-play replacement for what's on their gas-engines, so they don't have any further information, so I hope someone here can advise me.

Cheers,

Geoff,
Thailand

Title: Re: HobbyKing CDI ignition system
Post by: Tug-Kenny RIP on July 20, 2012, 09:09:39 pm

Is this  Boat  related  ?


ken

Title: Re: HobbyKing CDI ignition system
Post by: Andyn on July 20, 2012, 09:29:17 pm

Yep ;)

I do believe they need a regulated 6v supply to stop things getting smoky, either way it's a good idea to use one anyway... But I've heard good reviews of the units, only downside from what I've heard being the plug caps are naff. It's probably grounded through the engine, after all, it needs it somewhere. Internal resistance of a spark plug appears to generally be 0.5 - 10 ohms, not sure what it depends on, have a look at http://www.weaponxperformance.com/technicalPDF/SPARK_PLUG_TECH_V1.pdf

Andy.

Title: Re: HobbyKing CDI ignition system
Post by: HS93 (RIP) on July 21, 2012, 12:15:15 am

try this

http://www.justengines.unseen.org/acatalog/NewIgnitionIstructions.pdf

it may help

Peter

Title: Re: HobbyKing CDI ignition system
Post by: geoff p on July 21, 2012, 01:40:14 am

Peter: spot-on, thank you.

Andy: interesting reading, thanks.

Ken: not directly, which is why I put it in Chit Chat.

Thanks all,

Geoff

Title: Re: HobbyKing CDI ignition system
Post by: Andyn on July 21, 2012, 09:43:51 am

Don't take the J'en instructions as gospel, it's for a totally different system...

Title: Re: HobbyKing CDI ignition system
Post by: Tug-Kenny RIP on July 21, 2012, 09:53:35 am

No probs Geoff.

I'm learning all the time.


ken

Title: Re: HobbyKing CDI ignition system
Post by: geoff p on July 21, 2012, 10:06:29 am

Andy,
Nothing I do follows any gospel - I blame it on my singular vision (only one eye works, these days), so I mostly do things the Nelson way.

The information was/is great, sufficient to overcome my worries that I would let the magic-smoke out of a brand new unit.

I'm just about to rebuild the engine - there's always another 'mod' required - and see if the beast will run.

Geoff

Title: Re: HobbyKing CDI ignition system
Post by: Circlip on July 21, 2012, 10:58:24 am

Quote

Is this  Boat  related  ?

   If you choose to log onto their site Ken, you'll see the system fitted to an OS four stroke model engine. :-))

  Regards  Ian.

Title: Re: HobbyKing CDI ignition system
Post by: geoff p on July 21, 2012, 11:31:38 am

Slow-down, chaps,

Frankly, this engine is as boat-related as the Unimat 3 lathe discussion a couple of weeks ago: in fact it is the very same engine that illustrates Reply#1 on that thread.

This engine is/will be boat-related.  If/when I get the blighter to run, I have bright ideas of building a paddle steamer around it.  (Where I live there are no bylaws forbidding its use.  And it will be much quieter than some of the electrics I've heard.)

It's just an idea for now because I will have to work out speed control, as well as a reversing gearbox, and a mere elastic-band-drive to the paddle-shaft and ... and ....  Then I can start on the saw-bench to cut some planking.

Perhaps I'll achieve all this in my current lifetime, or maybe I'll have to come round again.

Geoff