Originally Posted by
J. Kłapacz
I am new in nitro, one engine I use for races successfully. Recently I start break in my second new Picco torque edox .12 and here's the question, after about 0.8l of fuel on the box and last 2 tanks gently driving, I checked the engine. There are small scratches, one quite clearly visible, what could have caused this and whether it will affect performance.
If you're new to nitro, then you probably haven't dealt with a ringless piston engine before. The entire side of the piston contacts the cylinder sleeve, and tiny scuff marks are inevitable. This is not "piston slap" like you would see in a ringed engine. Remember, aluminum is a soft metal, much softer than the chrome plating inside the cylinder sleeve.
It was probably caused by tiny bits of chrome flaking off the edges of the ports. I always clean the edges of the ports with a diamond jewelry file, and then wash the sleeve, before the first run to minimize these scratches, but there are always a couple scratches anyway, because nothing is perfect. Are the scratches deep enough to catch your fingernail? If not, then they're just cosmetic and won't result in any measurable change in engine performance. Such a tiny scratch, especially when filled with oil, will present so much resistance to leakdown that the scratch may as well not exist at all. You can worry about it if you want, and some people will be happy to help you in worry about it, but your driving skill, suspension tuning, and engine tuning will have orders of magnitude more effect on your lap times than these tiny scratches will.