When will you change your plug?
 

Hi gentlemans:
When will you change your glow [8D]plug?Is there any good rule to be follow?Thanks,,[8D]

RE: When will you change your plug?
 

When it fails. There are several different situations that could be a glow plug failure. One of the main ones is if it will not keep functioning after the glow driver is removed. This is usuall caused by the loss of the platinum coating or plating on the glow element. That is a necessary catylist for operation of the glow plug. When it 'wears away' for whatever reason, often by a to-lean mixture, it will fail to operate and quit after the glow driver is removed.

That's one theory.. I'm sure there are more, of course, the obvious, is when the coil just plain opens.

RE: When will you change your plug?
 

Like CGRetired said, change it when it quits working.

Ken

RE: When will you change your plug?
 

I only change them when I notice a problem in starting or bad idle. If the engine flames out I will check the plug as a possible cause as well.

I actually don't change the plugs often at all. Just keep a few in your field box and you will never need them :) but if you for some reson leave them on the bench at home, your bound for trouble[:@].

RE: When will you change your plug?
 

When I notice a change in engine performance, either starting, running or both. I might also change plugs ( perhaps unnecessarily ) if a plane/engine has been unused for a protracted period of time, say six months to a year. Just something I do to give it a "fresh" start after storage.

RE: When will you change your plug?
 

Isn't that Murphy's Law? And yes, Murphy is alive and well! ;) :D

One of our club members is a Pattern FAI level pilot. He did 'extensive research' on glow plugs. He is quite an authority on them and gave me the brief overview of what I posted earlier. You can replace them if you want, but unless it's really broken, and you can figure that out by swapping it out.. then they just don't go bad all that often.

RE: When will you change your plug?
 

Yes, Murphy is alive and well... I haven't seen him in a while and it makes me a little paranoid when I'm at the field latley:). Hopefully next time he comes for a visit, the gift he brings me won't be too bad.

RE: When will you change your plug?
 

I don't know if the long term storage plug change is necessary..

I flew my OS 45 FSR on a 20 year old idle bar plug for the first 3 months after I got it out of storage.
Changed to a #8 when it started having some idle issues... That was last year.. It's still going..

OS A3's don't last all that long for me..

RE: When will you change your plug?
 

Same as most, when I notice a decrease in engine performance or when it completely fails.
I just went through my field box the other day, there was 4 glow plugs in there so I tested them with my glow starter. 2 of them glowed orange 2 glowed bright yellow. I threw the 2 that glowed orange away.

RE: When will you change your plug?
 

If you are raceing, use a new plug for each race. Use the old plugs in practice. If you are not racing, change pugs when you see a problem. Or once a year if you remember.;)

RE: When will you change your plug?
 

I agree with the above. The only time I change it on a regular schedule whether it really needs it or not is with rare or very expensive aircraft - then I change it every 20 flights.

RE: When will you change your plug?
 

CGr stated his and some else's theory about replacing glow plugs when they don't work, that's a no-brainer. As Acs_guitars states that worn glow plugs do affect engine idle and transition, and clearly, he is also right on the money. A little less swagger and more facts would be appreciated.

Happy Landings!

RE: When will you change your plug?
 

when an engine starts giving me grief first thing i do is change the plug.

ive got plugs that have been in my aeroplanes since i bought them, i run my planes rich so they do last quite a while (come to think about it, in my year of flying ive not had one plug go bad on me, but i only fly once or twice a week and swap between which planes i want to fly ^^)

its like the saying "if it iches, it will be scratched", replace it when you need to but dont try and nurse the glow plug on for another few weeks because if it deadsticks on you at the wrong moment it can be difficult to get the plane down in one piece (speaking from experiance)

RE: When will you change your plug?
 

After breakin is complete i change mine, then when a problem exists in my sport planes.
Before the first flight of the competition in my competition engine. I recycle the old comp. plugs
and use them in my sport engines.

RE: When will you change your plug?
 

Last year I purchased several dozen plugs at $1.99 each.

I thought that this was a little high at the time...

These included 4C plugs and Fox Miracle plugs.

Now the price has more than tripled and the 4C plugs... OUCH!


I've gone through those plugs I changed out after engine break in, and all the others I changed on a whim debugging engine problems...

With the prices of these things now, I will be much slower in changing out plugs....

RE: When will you change your plug?
 

The quickest way to ruin plugs , glow or gasoline , is to lean out the engine too lean. Just a few seconds past the RICH peak does a nice job on the pretty coil turns inside .

Rich

RE: When will you change your plug?
 

When I remove the igniter if the engine drops RPMs A lot or dies completely then I change. By drops RPMs I don't mean the couple of hundred you usually get but if it really goes below the normal RPM range.

RE: When will you change your plug?
 

In 5 1/2 years, and 20 + planes with thousands of flights, I have replaced 4 glow plugs in my mixture of two and (mostly) four strokers. I average 4 to 5 cases of glow a year. 40-75 two stroke, and 82-120 four strokers power the majority of my fleet, with the exception of a couple of gassers. I NEVER run lean. Ever. Nevereverever. :D

RE: When will you change your plug?
 

Whats the difference between 4c and 2c plugs??? Which plugs seem to work the best of the two?
thanks

RE: When will you change your plug?
 

Heat range, A 4 stroke plug is A hotter plug because it has to stay lit twice as long between the compression stroke. I have used A 4 stroke on very old 2 stroke engines that are worn out and gotten more life out of them. You can do the same thing with an idle bar 2 stroke plug.

RE: When will you change your plug?
 

I have been away awhile, but it seems like we were using the 2c glow plugs with the bar on our 4c engines about 15 years ago. Has something changed ?????? I have some Saitos that I plan to put back into use this summer.

RE: When will you change your plug?
 

Actually it's not a "heat" difference when going from 2C to 4C or vice versa, as much as it is a slightly LONGER tip length in the plug.

That is why many 2C engines now come with 4C plugs as standard.

The slightly longer tip helps keep the element lit, particularly on inverted engines.

----

Idle bars are rarely used anymore.

RE: When will you change your plug?
 

Hi,
thats good info, I will be installing more inverted engines and will take this into account. We were using a onboard glow system on our inverted engines , is that still done with using the 4c plugs, eather 4c or 2c inverted or is there a better system or way to keep the glow in the glow plug???
This is great, thanks. Things have changed, but this helps a lot, don't feel like its going to be that hard with all this help at my finger tips.

RE: When will you change your plug?
 

I blew 2 plugs in succession starting my engine at the field one day. I was about to blow plug #3 when I looked down to see I had plugged the glow leads into the 12v starter jacks on my power panel.

RE: When will you change your plug?
 

I guess they needed to be changed.. and that's not swagger, is it.