The engine break in process is one of the most important and crucial steps for a great running long life engine. However for the end user it can be the most frustrating.
There are many different ways to break in these engines. Im not going to go over them all. Im only going to go over the best way and why.
The best method to break in your nitro engine is the hot oil lapping method. Most people using this are using the Smart Workshop's Smart Engine Lapping System. This submerges the engine in an oil bath as well as pumping oil through the engine.
This method is the best because of the many benefits it has while having no real drawbacks.
These systems heat the oil to a specified temp and holds it there. Once the oil is up to temperature they will start the lapping process. You dont really want to turn over the engines when cold. All of the materials are shrunk. When you do this you put alot of extra strain and stress on things like crank pins, rods and rod bushings, the piston and also the sleeve. You dont want this and doing it cold takes life out of the engine as it will lap the engine with the materials at the shrunken sizes. When the engine warms up and the materials expand the engine will be looser then you want. Heated oil also moves better and is able to penetrate deeper into places that need it. You want the engine to be broke in at the Normal Operating temps in pretty much any break in method and that is the same and executed even better with the hot oil lapping method.
The fitment of the parts is very important. With the hot oil being pumped through the engine during this process it helps flush out debris during the process and keep every surface supplied with lubrication. This creates a perfect and far superior fitment between the moving parts. This fitment will be far more precise and perfect then any other because of the controlled environment its being done in as well as process consistency. Running and engine in has alot of variables and outside factors that can affect this process. Because of the lubricant its submerged in and it being rock solid at normal running temps and ran at an RPM that is very low its way less abuse on the engine during break in. Running in new engines it wasnt uncommon to replace the rod after the engine was fully broke in. This is due to the extra stress and wear put on the rod by running it in. The hot oil lapping process you dont need to do that at all. I also believe this process over any will give you longer life out of the wearable items like crankshaft pins, rods, pistons, and sleeves.
This one is a big one. Having an engine run in for you from the factory or someone do it usually costs $100-$150 USD because the process is so demanding and long. You have to monitor the engine and keep it fueled up, check the temps, adjust RPM and the carb and also heat cycles. The hot oil lapping process is around $40-$50 USD. Thats way more inexpensive and you get a way better end product. You also dont have to worry about the hidden costs like going through glow plugs, and a gallon of fuel that has gotten very expensive.
I know REDS uses the hot oil lapping method from the factory as an option. Use it unless it increases the price over the non broken in engine for what you can have someone do it for. There may be others offering it but im not sure. There are two that do this as a service as well. One is Adam Drake and the other is Ed Bridges of EBMods. EBMods. If i picked between the two id pick EBMods. Ed knows more about engines then Adam Drake and Ed also makes his own tools and improves his own tools. He also has the knowledge and experience to do it the right way and has the tools to truly measure things to make sure. This isnt a slight on Drake, hes a damn good pro driver for a decade now. Ed is basically an engineer and Drake is a celebrity driver. Drake doesnt know nitro engines to the degree that Ed does. I think Ed has his process fully refined and thats why his is the cheapest.