Break in procedure

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
2

2simplistic

Member
Messages
7
Reaction score
0
What is the break in procedure for the XB? I just received mine today and the manuals that came with the XB were for a nitro vehicle. Thanks.
 
The the low speed needle to 1 1/4 turns out and the high speed needle to 1 1/2 turns out. That is the factory settings. Break in procedures differ. I prefer to idle a tank while blipping the throttle by hand every minute or so to about 1/2 throttle to clear out oil buildup. The next tank I run the car. I limit my throttle to 3/4 and only run it at that for a few moments at a time. After that let er rip.
 
Fuel it up and drive. Higher RPM's will help the ring seat properly. If the ring doesn't seat properly, your engine won't run at its full power potential.
 
If you idle 1 tank and then pull the head you can really see all the hills and valleys caused by the plating process. All the shiny areas will be hills and the dull areas will be the valleys because the ring does not make proper contact with the cylinder wall. As you run your engine more and more the hills (shiny areas) will start expanding into the dull areas. Your objective is to even the plating out to where the ring makes 100% contact with cylinder walls causing the entire wall to be shiny. This usually happens around tank #5 or #6.


Just a warning... High RPM's will break in the engine much faster, however, I don't recommend you doing that untill you get a good tank in with medium speeds and short WOT bursts here and there. The reason is that you have a greater probability of a lean seize from the piston catching the exhaust port. The new lumpy plating causes alot of friction/heat. If you do not have your piston relieved, the ledge above the ring will expand from the heat and snag a bevel on a port. This happens mostly on the exhaust port. The reason it happens mostly on the exhaust side is because that side of the piston is hotter than the intake side due to the exhaust gases exiting in that area. I'm also sure the fact that the intake side faces the front of the car (airflow) and the fact that the air from the flywheel is directed to the front of the engine also is a factor.


Also I would like to mention that I've seen a buddy run WOT a little too long on the first tank with no lean seize. I've inspected the piston through the exhaust port however and have seen scratches on the piston. The cylinder wall itself had hairline scratches too. The engine would still run fine though. It was good enough for him I guess. He would never have noticed if I didn't say anything. The problem was it ran like a stock 27.2 when it was an ONB Full Mod 30.5.
 
Back
Top