While flying the other day, my engine died for no apparent reason. It's a new engine--first in air flight, but I broke it in as per the manual beforehand. It was at wide open throttle, and at six minutes into the flight, at level flight, it just died. Upon inspection, the glow plug coil was gone. Just gone. I guess it burned out. This glow plug had been used on one of my other engines, and had about 4 gallons of fuel on it. Was it just time, or what else would make a glow plug just burn out in mid air?

Too lean, or being a new engine could do it. More than likely "it was just time". Four gallons, and from another engine? Yeah that would do it.
I've broken in a few, and the glow plug barely lasted long enough to break it in. Maybe a metalflake ate the element.

Breaking in a new engine often costs at least one glow plug, probably from the effects of the high amount of foreign particles generated as an engine wears in contaminating the plug.

4 gal. of fuel!! [X(] You got your moneys worth out of it. I know guys that get one weekend or others that get one flight (racing) out of a plug. They can only handle so many cycles of running before they will just fail no matter how perfectly you tune the engine. [8D]

It was time. Keep lots of extras. You got good use out of that one. [8D]

I had a coil drop out of a glow plug into an engine a couple weekends ago. Finished a nice vertical climb and when I reducec throttle the engine started running very roughly. It died when I cut it back to land, and when I turned it over you could feel binding at TDC. Pulled the glow plug and the coil was gone. Pulled the head and found some small balls of metal on top of the piston, which I removed. Engine ran Ok afterwards, but later that week it lost compression and was retired. I didn't see any scoring on the cylinder liner, but the piston might be or the ring could be broken. Watch that engine for a few days.

Andy

I can't understand the logic of using a recycled glow plug on a brand new engine.

Well, if it's the only one you have, and you work 7 days a week--and are always at work when the lhs is open, and just dispise shipping costs on little things like glow plugs, then there is your logic.

I HAVE FLOWN ALL SUMMER ON THE SAME PLUG. I HAVE BURNED AT LEAST 4 GALLONS OF FUEL THREW THE THIS PLUG WOULD IT BE WISE TO CHANGE IT NOW?

If it ain't broke, don't fix it. Run it until it dies! You're not going to hurt the motor (I don't think!)

Reference my post above. Although that's the first time I've ever heard of the coil dropping out completly... and BTW it was an OS brand plug.....


Andy

I've had engines suck the coil out of the plug a few times. I've even pulled a blown plug to find the element hanging there, pulled well out of the plug body. I've had plug elements "mashed" up inside the plug body, and elements just missing. I've never had an engine get badly damaged by a plug element, but I have found scratches on the piston/liner that I can't account for any other way, and I've found bits of metal on the exhaust port that weren't there before (a bit of work with a file and emory cloth fixed that one). But I've never had an engine loose real performance from a plug element. But I've seen it happen to others. I think it's pretty rare though.

4 gallons, yep, that's a darn good plug lifespan. Btw, I happen to use K&B plugs in most of my engines. I order them direct from K&B over the phone, usually 12 at a time, which last for quite a while. (keep in mind, I fly a LOT of combat, I currently have about 15 engines just for combat. Plus sport engines).

A glow element breaking loose is enough to lock up and ruin a 1/2a engine[],..knock on wood it hasnt happened to me yet..Rog