My head blew it's top!

**Cribbs74** Wed Dec 07, 2011 10:49 pm

Seriously it did, a first for me. .010 head brand new. Fired of ran for about 5 seconds and puff! Center post shoots up like a jack in the box. I push it all back in and tapped the collar down snug. The plug still glows but no compression. Ebay purchased......anyone experienced this?

**RknRusty** Wed Dec 07, 2011 11:15 pm

Never. Do you think it was a Cox old stock part? It wasn't from Bernie or Matt was it?

dckrsn Wed Dec 07, 2011 11:22 pm

cribbs74 wrote:Seriously it did, a first for me. .010 head brand new. Fired of ran for about 5 seconds and puff! Center post shoots up like a jack in the box. I push it all back in and tapped the collar down snug. The plug still glows but no compression. Ebay purchased......anyone experienced this?

Ron-Truely a "WT#" moment.

Never even heard of this happening.

Thinking about it, with the dissimilar metals/compression/heat, I'm suprised it hasn't happened more often.

I like the "jack in the box" reference. Funny visual. Laughing

Last resort, heat the head good and hot and press the post in tight with some sort of clamp or vise arrangement

and let it cool.(duh)

Hope there's some chimers in the wings.

Bob

nitroairplane Thu Dec 08, 2011 2:46 am

That sounds very unusual but as ha been said doesn't seem like it should be.
Maybe press it back in until it is at the point t should be and then maybe a little JB weld.

Kim Thu Dec 08, 2011 6:38 am

dckrsn wrote:
cribbs74 wrote:Seriously it did, a first for me. .010 head brand new. Fired of ran for about 5 seconds and puff! Center post shoots up like a jack in the box. I push it all back in and tapped the collar down snug. The plug still glows but no compression. Ebay purchased......anyone experienced this?

Ron-Truely a "WT#" moment.

Never even heard of this happening.

Thinking about it, with the dissimilar metals/compression/heat, I'm suprised it hasn't happened more often.

I like the "jack in the box" reference. Funny visual.

Last resort, heat the head good and hot and press the post in tight with some sort of clamp or vise arrangement

and let it cool.(duh)

Hope there's some chimers in the wings.

Bob

The Last Resort +...send it to me, and I'll try to stick a glowplug in it !

**Cribbs74** Thu Dec 08, 2011 8:33 am

RknRusty wrote:Never. Do you think it was a Cox old stock part? It wasn't from Bernie or Matt was it?

Rusty,

No, not from Matt or Bernie but, a new part in unopened cox packaging.

**Cribbs74** Thu Dec 08, 2011 8:38 am

dckrsn wrote:
cribbs74 wrote:Seriously it did, a first for me. .010 head brand new. Fired of ran for about 5 seconds and puff! Center post shoots up like a jack in the box. I push it all back in and tapped the collar down snug. The plug still glows but no compression. Ebay purchased......anyone experienced this?

Ron-Truely a "WT#" moment.

Never even heard of this happening.

Thinking about it, with the dissimilar metals/compression/heat, I'm suprised it hasn't happened more often.

I like the "jack in the box" reference. Funny visual.

Last resort, heat the head good and hot and press the post in tight with some sort of clamp or vise arrangement

and let it cool.(duh)

Hope there's some chimers in the wings.

Bob

Yep, it did everything a jack in the box does except no "pop the weasel" music or boing sound!

It is comprised of a coil glow spring, packing/sealing gasket center post and beveled press fit collar to lock everything in place.

I push it back in the same way it popped out except now I can see air bubbles and castor coming up around the center post.

**Cribbs74** Thu Dec 08, 2011 8:40 am

nitroairplane wrote:That sounds very unusual but as ha been said doesn't seem like it should be.
Maybe press it back in until it is at the point t should be and then maybe a little JB weld.

Good idea, except I already snapped it back together and It doesn't want to come apart!

**Cribbs74** Thu Dec 08, 2011 9:00 am

Kim wrote:
dckrsn wrote:
cribbs74 wrote:Seriously it did, a first for me. .010 head brand new. Fired of ran for about 5 seconds and puff! Center post shoots up like a jack in the box. I push it all back in and tapped the collar down snug. The plug still glows but no compression. Ebay purchased......anyone experienced this?

Ron-Truely a "WT#" moment.

Never even heard of this happening.

Thinking about it, with the dissimilar metals/compression/heat, I'm suprised it hasn't happened more often.

I like the "jack in the box" reference. Funny visual.

Last resort, heat the head good and hot and press the post in tight with some sort of clamp or vise arrangement

and let it cool.(duh)

Hope there's some chimers in the wings.

Bob

The Last Resort +...send it to me, and I'll try to stick a glowplug in it !

Kim,

Seriously considered that but, a screw in glow plug is about 3/4 the diameter of a .010 head plus even if it worked I would have to purchase a new clip arrangent for that head only. So cost wise it may not make sense.

I put the old one with wrench marks on the fins and it works fine, looks crappy though. Kinda angry now that I am out $13.00.

Cox International Thu Dec 08, 2011 10:22 am

Ron,

It sounds as if the parts were not properly pressed. It happens on rare occasions. It will be nigh impossible for you to re-press same without the special tooling.

BTW any items you (or anyone else) purchase from us are unconditionally guaranteed to function, meaning that if someone bought a glow head that malfunctioned on first attempt, we would replace it.

Bernie
www.coxinternational.ca

**Cribbs74** Thu Dec 08, 2011 10:31 am

Cox International wrote:Ron,

It sounds as if the parts were not properly pressed. It happens on rare occasions. It will be nigh impossible for you to re-press same without the special tooling.

BTW any items you (or anyone else) purchase from us are unconditionally guaranteed to function, meaning that if someone bought a glow head that malfunctioned on first attempt, we would replace it.

Bernie
www.coxinternational.ca

Bernie I may try heating it and see if I can get it to seal. Good to know you stand by your products. In future I may buy all my parts through the "real Cox distributors" like you and Matt. Sometimes deals come up on ebay that are too good to pass up. For example I found a new in cox package .020 head for 2.95 buy it now. I snatched it quick......

EXModelEngines Thu Dec 08, 2011 10:53 am

Sounds like a defect with the core and/or assembly as Bernie mentioned.

Same thing happened to be on an 049 engine a while back. Apparently the assembly wasn't pressed correctly and the glow head core was broken in two before running. After a minute of running part of the core got loose. No nearly as extreme as your case, but it happens I guess, albeit rare.

Matt

nitroairplane Thu Dec 08, 2011 11:36 am

This has never happened to me.
Infact i rarely even burn glow plugs I guess i am lucky with them.

SuperDave Thu Dec 08, 2011 11:45 am

I can attest to Bernie's credibility when replacing faulty glo-plugs. One that I got from him didn't want to thread properly.

Sent a note to Bernie and he replaced the plug. I was curious that the package had been opened but then realized that Bernie had checked the threading on the replacement plug prior to sending it.

With sevice and consideration like that I am a dedicated fan of Bernie!

nitroairplane Thu Dec 08, 2011 11:47 am

I have only made 1 or 2 orders from Bernie and it/both arrived quickly and i recieved 2 .020 springs and not one.

microflitedude Thu Dec 08, 2011 1:26 pm

What is the black material around the center? Could it have become brittle?

nitroairplane Thu Dec 08, 2011 1:41 pm

microflitedude wrote:What is the black material around the center? Could it have become brittle?

I suppose it could but I don't think that would make it pop out.

Cox International Thu Dec 08, 2011 1:48 pm

The upper and lower insulators are made of either Nomex or Quinargo; in between the 2 is a steel washer.

Bernie
www.coxinternational.ca

nitroairplane Thu Dec 08, 2011 1:50 pm

Maybe you should but on of these if you need to know more.

gcb Sat Dec 10, 2011 3:16 pm

Actually...I had this happen on a PeeWee when they first came out. Got it home, fired it up, and POOF, no compression. The insulation had blown. It still glowed. I went back to my LHS and bought a new plug... $0.49.

I chalked it up to being a new product. That's the only time I had that happen on ANY type plug.

George

Edit: Additional thought. When I got that engine, the props had not come in. I cut down a 5x3 Tornado Plasticote and balanced it with my primative razor blade balancer that most of us used at the time. Those were the days...

**Cribbs74** Sat Dec 10, 2011 11:55 pm

George,

I think the .010 heads are different as they have no insulator, just a locking collar, center post, packing disc and the glow wire. At any rate I heated the head back up and gave a tug on the center post and it came out so quick that I ripped the glow wire off.

So I may take the route Kim took and see if I can convert it to a regular thread in type glow head. Not sure about compression issues though.

gcb Sun Dec 11, 2011 1:26 pm

Ron,
I believe the packing disk is an insulator. The center post must be electrically isolated (insulated) from the rest of the plug or you will have a short which will cause the wire to not glow.

George

**Cribbs74** Sun Dec 11, 2011 4:12 pm

gcb wrote:Ron,
I believe the packing disk is an insulator. The center post must be electrically isolated (insulated) from the rest of the plug or you will have a short which will cause the wire to not glow.

George

Yes, you are correct. It is an insulator, as in it does seperate the bottom portion of the post from the head except the metal snap ring that holds the whole assy in place touches the post and the head. Let me go take a pic real quick......

SuperDave Sun Dec 11, 2011 5:51 pm

Ron:

Considering the tiny size of the .010 I doubt if you'd find a standard glo plug small enough to fit.

New .010 glo-heads are available from Bernie @ $12.95 IIRC.

nitroairplane Sun Dec 11, 2011 5:56 pm

No you would not as the smallest glow head is the .010 one but you could turn down a .020 head to fit and the first runs of the tee see .010 were made with a turned down .020 head.

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