OS SX-H Hyper Blowing glow plugs
 

Every full tank flight on my Raptor 50 it blows the glow plug. The plug looks new when I take it out. When I land, I can stick my finger to the back of the crank case hole, and it's hot, but I can hold my finger there and not get burned. I can touch the head, it's hotter but not hot enough to burn you. When running, it's blowing a good smoke trail so I know it's not lean. I run a GV-1 governror with the head speed at 1850. The engine has good power, it will go vertical to a the size of a period in just a few seconds.
I removed the muffler, the piston and sleeve look good, no scars, browning or anything out of order I can see from there. I run Wildcat Heli mix 20% on my other Raptors 30, and 90 sized, both OS engines with no problems.

RE: OS SX-H Hyper Blowing glow plugs
 

sounds like u r running the motor to lean.....even though u have a nice smoke trail.....

RE: OS SX-H Hyper Blowing glow plugs
 

Have to agree on the lean run. A smoke trail indicates that there is sufficient oil in the fuel, not that the mixture is lean or rich. Have you tried pinching the fuel line at full power? If the engine dies quickly, you are too lean. The rpm should rise some and then the engine should start to slow down. If the engine keeps running at the same rpm for quite a while, then the rpm begins to rise, you are too rich. The same test can be done at idle to check your idle mixture.

RE: OS SX-H Hyper Blowing glow plugs
 

Yeah I would have to agree, but the engine never hits full throttle, when it lands, I can touch the back of the engine, you know the little hole by the crank, and it's cool, the head is hot but I can hold my finger on it 3 to 4 seconds.

I went yesterday for example, made the thing so rich it ran like a 30 on my 50, and flew figure 8's for a full tank. I'm just learning orentations now anyways so that is what I fly, every now and then a loop or roll but mostly just working on orentation.
The engine was cold when I landed. Tried to restart, dead plug.

Could running to rich kill the plugs? They look perfect when they are killed, can't tell em' from a new one just they wont light anymore.

RE: OS SX-H Hyper Blowing glow plugs
 

When you mention that you're "blowing" a plug, what does the plug look like when you take it out of the engine? If the element is all twisted up or gone, then you're getting detonation. Detonation is caused by a too-lean setting, or a too-hot condition. Over-revving could also cause the plug element to be deformed or broken.

Is the element still there but a dull gray color? That could be due to metal contamination. That happens when you have too little oil in the fuel or corrosion starting in the bearings. Corrosion products will kill a plug fast. So will any metal that's coming from the engine's internals. Brand-new engines will "make metal" a bit while breaking in, but usually not after a gallon or so of running.

Does the element look like it has a drop of glass on it? That means dirt damage. Dirt can come in through the fuel or the air intake.

Finally, check your starting battery. If it's not a 1.5 V dry cell or a 1.2 V NiCd, but something different, you may be applying too much voltage to the plug and burning it out that way.

You'll need to go through all the possibilities. Even a too-lean run. If you are too lean, but running at reduced throttle settings, your engine will get too little lubrication and still be fairly cool.

RE: OS SX-H Hyper Blowing glow plugs
 

Sorry for the delay had a small surgery yesterday.

The plug looks new. No bent wire, nothing. You can't tell it from a new plug. It breaks the wire down towards the bottom somewhere, I pulled one out and it's clean.

I don't use and gasket compound just metal gaskets or jb weld, but this one has a metal gasket that looks perfect also.