Glow plug life?
 

So I have a product engine I converted to SPI. It really screams now and is a blast to fly.

I am running 30% nitro w/ 14% synth/castor blend.

Assuming I do not over-lean....what sort of lifespan can I expect out of the plug?

-Dave

RE: Glow plug life?
 

You can get from 1/2 to a whole season. The one caveat is, all it takes is one sharp dive where the engine revs get ridiculous and the coil could get toasted. I use 10-15% and get excellent life out of my plugs, but when I got to higher nitro things change to the worse.

RE: Glow plug life?
 

only 14% total oil? Seems kinda low.

RE: Glow plug life?
 

Back in the 60's (and internally the cox engines are still in the 60's) Cox wouldn't honor the waranty if you didnt run oil that was all castor and 20%.... so my guess is that you will get more life out of the plug than you will out of the connecting rod/piston ball joint. Do you have a reset tool? You will need it. Castor gets into the ball joint and helps... synthetic keeps the engine cleaner but doesn't do a very good job of protecting it from wear.

RE: Glow plug life?
 

14% oil for a COX is way too low. Get some castor from any Any Town Drug store.

If you add 1.75oz to 16oz of your 14% Oil / 30% Nitro brew you will end up with... 22.5% Oil / 27% Nitro.. A much better formula for the Cox.

The engine will run cooler and be kinder to plugs.

Corrected volume of fuel to be modified... Thanks Big Al.

RE: Glow plug life?
 

And may very well turn more RPM to boot.

RE: Glow plug life?
 

Steve, I believe you meant to say add 1.75 oz castor to a pint (16oz) or 3.5 oz to a quart.
Al

RE: Glow plug life?
 

How long is a piece of string?

I have some glow plugs from the 80's that still run strong. I've had others that lasted 5 flights. I can't honestly answer how long a glow plug will last. How often you fly, the engine rpm, fuel ratios, and the percent of gremlin installed at the glow plug factory will all have an effect on plug life. All I can say is fly until the engine quits, then put another plug in it. Always carry spares.

RE: Glow plug life?
 

That is what I thought....I have some from the 80's as well.

My larger engines make it a season or so, but that is on 15% nitro.

-Dave