Engine eating glow plugs

[Sieze2]

So I seem to be using about a glowplug a gallon for the last 3 gallons. The engine is running cool and rich, and has no rattles from cold. I have read that this could be a sign of the rear main bearing failing as the particles of metal damage the glowplug. Is it time to pull the engine and change the main bearings ? Its an Align 91 H (OS 91 Hz) with 15 gallons use (with a Rob GT set headspeed - its set somewhere between screaming and wailing)

If so where is a good place to source replacement (non OS price) bearings? somewhere online and in the UK would be ideal.

[del19_82]

Could try Here for bearings mate.

[robgt]

Before reading the content of this thread (just the subject line) my first thought was the back bearing!

Last time we flew it Oli, it was tuned nicely , so I doubt it's lean runs killing them?

Cheers,
Rob

[Sieze2]

Before reading the content of this thread (just the subject line) my first thought was the back bearing!

Last time we flew it Oli, it was tuned nicely , so I doubt it's lean runs killing them?

Cheers,
Rob

Do they usually only last 15 gallons or so rob? (I do have an issue with fine sand where I fly near home). Where do you source your bearings from? Ever had a problem with metal caged ones?

[robgt]

I've bought aftermarket bearings from Modelbearings previously - as linked above.
How long they last will vary depending on lots of things.
The sand issue you have won't help matters I'm sure.

To be honest, 15 gallons isn't great, but it's not terrible either...

Cheers,
Rob

[jamiem]

my 50 hyper is eating them at an alarming rate, as in one every other flight. ive replaced the rear bearing and the ring to no avail. im a bit stuck on this one, its tuned fine, not running lean at all

[robgt]

If that's in your Knight 3D, have a chat with Richie as he went through the same problem, but I think got it resolved?

Cheers,
Rob

[jamiem]

ill pester him on msn sometime soon, cheers

[Sieze2]

I also heard using a silicone sealant to seal the exhaust to the engine can cause premature plug failure (alothough I find it hard to believe). Might be worth considering though Jamie.

[robgt]

Yes, it can - if any excess makes its way back into the engine it will kill a plug.
Cheers,
Rob

[barney]

my 50 hyper is eating them at an alarming rate, as in one every other flight

Apart from the obvious running lean..does it hve the Death rattle at idle? (bearing)

Assuming not I would reckon something is out of balance/alignment like the clutch in the motor stack.

A partly split clunk line may cause it to run lean part way through the tank but OK on full. So it's a good idea to check temps throughout the tank..e.g. 1/2 1/3rd.

cheers Brian