glow plugs

[steve01]

can someone explain to me why the coil element in my glow plugs have a tendancy to be pulled out of the plug during operation, i have a feeling it has something to do with the tuned pipe length but not sure :confused:

[Ron Olson]

If it's pulling out, you did everything right! Not a lot of people can say that, good job!

[MarcRacer18]

HMM, that might be why my glow plug looks funny, any idea how long it takes a "good" running engine to do that?

[Ron Olson]

Not long. You can help out any glow plug by pulling out a coil out beyond the plug to help the fuel burn better. Do this with a new plug then temper it by hitting it with a glow ignitor for a couple of seconds outside of the engine.

While we're at it, here's an article that I typed up for another forum site to help out in reading plugs:

I'm taking liberties here but this was taken from the June 1998 issue of RC Boat Modeler magazine from a well-written article by John Finch. I changed some of the wording to shorten things.

Shiny element
Your engine is set rich and the head clearance, fuel and pipe are close and are running well.

Dull element
The frosted coil will have an "orange peel" appearance to it. This is telling you that you are running lean but your head clearance is OK.

Shiny or dull mangled element
This is telling you that you don't have enough head clearance. Add a shim or shims until the problem is solved.

Frosted, missing or mangled element
This is a sign of being too lean, not enough head clearance or both. Try richening the carb to see if it's the carb or if you need head shims.

Shiny but mangled coil
If the engine is rich and the coil is mangled then the head clearance is too tight.

Black element
This is not a good sign as the engine could be getting ready to go south. It's time for new bushings and/or bearings as it's eating up aluminum parts.

Small tiny flakes on the coil
Pretty much the same as above as your bearings are on the way out.

Plug dull and pulled out
This is where you want it to be! This is showing you that the needle and pipe are right where you want them.
__________________

[Sublime_Slayer]

I really do learn something new every day! Nice! :D

[USMC & Viking]

I would like to have "Post# 4 a Sticky".....

How bout it Mods?

USMC & Viking...! & Little Jack...! :)

[USMC & Viking]

Ron,
I reported your post to have it made into a "STICKY"

Thanks for this info.

USMC & Viking...! & Little Jack...! :)

[Ron Olson]

It probably won't happen. Usuallya sticky is devoted to a large ongoing subject like props. Glow plugs are just like spark plugs, if you know what to look for then it can tell you a lot about what's going on inside the engines.

I just pick up things here and there on plugs, the trick with pulling a coil or two out came from Andy Brown and his brother John. When they sold the MAC enigines they found that this little trick greatly helped in combustion thus more HP and RPM.