Hashem

I read an article about glow problems.
Then the article talked about glow plug stem seal!
which I haven't heard about it!
does anyone know what it is? and post a picture of it for me

thanks

aspeed

I have a bunch of Fireball plugswhich the cool heat rangestands up to nitro very well. The seals blow between the housing and the stem. It is an insulator so there is no electrical contact which would short out the plug. I don't think my camera can go that small. It isn't usually a problem unless the motor runs very hot or there is a lot of compression.(or if they are Fireballs)

downunder

It happens every so often. The post can come loose and the engine loses compression past the seal. If an engine suddenly seems to have lost compression then that's the first thing to check by just dribbling a little fuel around the top of the plug and look for bubbles when you turn the prop over.

jeffie8696

Ihave only seen it in ancient Cox plugs and some Fox plugs.

Hashem

the article was about the above problem!!
I uploaded a picture!
is the pointed part a stem seal?! see the picture

jeffie8696

Yes, that is what he is talking about. If a liquid is poured onto this area and the engine is turned over you will see bubbles there if the seal is bad.

w8ye

My Feedback: (16)

That's it. That's where the bubbles come from on a bad one.

Four Stroker

There was a brand of plugs once with a glass seal. This would shatter and the entire stem would blow out when the engine was running. I saw an add recently for the same plug - new name. It's like magic sunglasses. There is a warehouse full of them somewhere and they reappear every ten years or so.