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Old 04-16-2020, 06:25 AM
1QwkSport2.5r's Avatar
Join Date: Oct 2006
Location: Cottage Grove, MN
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Preheat the head to 200F, start engine, and drive it. Adjust the low speed needle so it will idle and clean out easily but not a full on tuned/lean setting. Set your high speed so on a good 2-3 second WOT pass the engine temp cools off. Basically you want it to build some heat and hold it at the lower throttle settings and cool off on a WOT pass. This is keeping the temp within check and providing extra lubrication.

My break-in fuel consists of 4 quarts of fuel (1 US Gallon).
Quart 1 is 14% oil - 12% castor 2% synthetic
Quart 2 is 13% oil - 11% castor 2% synthetic
Quart 3 is 12% oil - 10% castor 2% synthetic
Quart 4 and beyond is 11% oil - 9% castor 2% synthetic

Use a fuel with a castor synthetic blend - starting with a race fuel with 8-10% oil works best - add castor oil only to the fuel. As you add oil, you reduce the nitro by a little bit. Not a big deal. Simple math formulas will tell you how much oil to add for a given step. I run extra oil and a leaner needle setting. This keeps the engine hot enough while still adequately lubricated. Hereís a video of how I break engines in. Note, this is the end of the first quart. This engine has a gallon and a quarter through it and the pinch is still exactly like it was from new. (I built this 3.3 completely from spares and modified it.). Break the engine in with purpose - not paranoia. Too cold and too rich isnít good just like too lean and hot isnít good. You may need a wider idle gap and hotter glow plug for the first half gallon, but afterward, go to a medium get plug and run a 0.5-0.7mm idle gap. Modifying an 1/8 scale carb is a good way to get a better operating carb than the Traxxas carb, but that requires some finesse.

Last edited by 1QwkSport2.5r; 04-16-2020 at 06:35 AM.