Piston is discolored

[JSY0829]

I took off the glow plug to put some ARO in and the top of the piston has a funky color to it. I expected it to be silver but it's sort of a carmel color. This can't be normal right? Any idea what's going on?

TIA

 

[RcTire]

what kind of fuel you running?

 

[vbgagnon]

It is normal. Piston's tend to get some build up on them after running a while. I wouldn't be worried unless it is thick enough to say there is buildup.

 

[JSY0829]

what kind of fuel you running?

Trinity...20%

 

[4u2nv]

Thats normal. Its the residue from combusted nitro.