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Building Tips and technical articles. => 1/2 A building. => Topic started by: Chancey Chorney on February 10, 2009, 06:12:33 PM

Title: Burnt out Cox glow plug wanted (.049)
Post by: Chancey Chorney on February 10, 2009, 06:12:33 PM

Hi there. I have just rebuilt a Cox .049 engine and am missing the final ingredient. A glow plug. Would anybody happen to have a old burnt out non-working plug that I may aquire. I would like to try and make it fit a standard glow plug. I like little projects. I know I can buy them, or even a Cox glow plug head adapter, but I love to tinker. I also know that if I suceed, it would not be as good as the name brand head adapters, but I do not care, as this is just something I would like to do for myself. If anyone out there can help, please pm me. It would be greatly appreciated. Thank you.

Chancey

p.s.  this has been posted on another website as well(r/c site), so if you saw it there please disregard

Title: Re: Burnt out Cox glow plug wanted (.049)
Post by: jamtx on February 11, 2009, 11:23:55 AM

 email sent.

Title: Re: Burnt out Cox glow plug wanted (.049)
Post by: Russell Shaffer on February 11, 2009, 11:39:19 AM

Seems that you have at least one - I have one in front of me that you are welcome to. 

Title: Re: Burnt out Cox glow plug wanted (.049)
Post by: kenneth cook on February 12, 2009, 02:45:10 PM

           I tried it with little success. The engine did run but performance was way down. The other problem I encountered was the initial tap hole was well into the area that the wrench fits. The area the wrench fits onto ripped off after a few installations. I think with a little patience I could of fixed that problem. I think the ideal situation here is to put a tapered seat into the plug then tap for a turbo plug. I think this would at least put the compression ratio back into play. I also removed the last fin to try and make the head screw into the cylinder more but this didn't help either. Ken

Title: Re: Burnt out Cox glow plug wanted (.049)
Post by: Pinecone on February 14, 2009, 01:41:33 AM

As per the other sites.  This is the worst option.

Galbreath is #1.  Valentine head for Turbo plug is #2.

And also very good (although reports are the Galbreath works better) is a Cox glow head.

Title: Re: Burnt out Cox glow plug wanted (.049)
Post by: goozgog on February 15, 2009, 04:43:31 AM

Hello Chancey,
                    I tried this too. I was going to post
a picture but it's self explanatory. I just drilled and
tapped a hole in the Cox glow head and installed a
short reach plug. The results were underwhelming!
  The engine ran weakly, but it did run. I was
carefull that the plug reached as far as possible into
the combustion chamber. I think that a standard
plug has too much empty volume cut inside it and
this reduces the compression ratio.
It was a fun experiment.

Cheers!

Title: Re: Burnt out Cox glow plug wanted (.049)
Post by: Chancey Chorney on March 23, 2009, 08:08:24 PM

Well, project done.  Got it built and short reach plug in right now, but will also try long plug too so I may see if there is any difference.  Thanks to all for their help with a couple plugs for this experiment, as well as support to do this.  Will post pics in a couple days.  All I had available was a standard 1/4 - 28 nf tap, so I used that.  Head was soft, and the regular plug screwed in without much effort.  I have a thick type of fuel and chemical resistant teflon tape that I will also be trying out.  Will not try out for a little bit yet as snow is still here, we are gettin a big storm moving in right now from the Dakotas, an we are in flood warning too.  Sandbagging has already begun around here.  But will do a post run report when it happens. 

Chancey