Colour ( color ) of piston crown

[mewsikman]

Hey guys,
I have just taken out my glowplug because I was having some idle issues and while the plug was out I had a peek at the piston crown to see what colour ( color ) it was...

I was quite surprised to see that the crown was a light brown with one or two very small dark brown patches and on the left side ( looking into the piston ) of the crown you could see the original finish

Sorry if that makes no sense but can someone please tell me if this is normal or not

Many Thanks
Alex

[DebianDog]

I would think a medium to dark brown would be right. Black is too rich and light gray is too lean.

[eurylokhos]

You're fine with what you described.

Funny side story regarding the spelling of the word Color (colour). Growing up, my father was stationed at RAF Upper Heyford, and I was going to school at Croughton Elementary in England (A USAF school with American teachers). I was in 2nd grade or so, and the word color was on my spelling test. I put down "Colour", since that's how it was spelled everywhere I looked, and on TV in commercials for detergent and what not. My teacher marked it wrong, and I got detention for fighting with her about it, my first detention ever. I still say that she should have marked it right, I spelled it appropriately for the country I was in, and I maintain that to this day, probably 25 years later!

[DebianDog]

and I maintain that to this day, probably 25 years later!



Dude let it go. :lol: Is is grey or gray?

[eurylokhos]

Dude let it go. :lol: Is is grey or gray?
I dunno, and it's a long flight back over to England to get a spelling test to find out.

[rototiller]

A nice rich heli motor should have very little carbon deposit on the top of the piston. If there is some it would be near the ex port. If your whole piston is covered in carbon its at max power and you should back it off a little. Too much leaner than that and it will start to look lighter and possible burn a hole in the piston.

The fuel you use will have an effect on the color and amount of carbon on the piston also, so you have to take into account for that.

Either way, airplanes and helis should be run rich enough to keep carbon from attaching to the piston. I took my hyper apart after 10 gallons and had a touch of carbon near the ex port. My motor runs between 180 and 200 deg with enough power to pull max pitch without bogging.

Merry Xmas
DK

[AutumnSummers1]

My hypers piston top is the color it was when it was new and 10 gallons ran threw it
still runs as good as new ,not 1 problem 3dx fan, cy30%, 60 clicks out on high speed
factory on the low speed. head speed - normal -1750 - s1 1850 - s2 1950, gv-1, align pipe

[mewsikman]

my low end is very unresponsive do I need to adjust the mixture screw??? Do I need to lean it out???