Coventrywoods

I received this engine used in a package deal. It ran but was pretty worn. I put new piston , sleeve & crank in it. Break in method was as follows.
Carb 21J ... H1.2 in from flush , L .5 in from flush , mid flush per Adam Drake YouTube vid on this engine
4 idle tanks @ 180 degrees , piston BDC cool between
Driving ....
1st tank 1/4 throttle on off / 180 degrees
2nd tank 1/2 throttle on off / 180 degrees
3rd tank 3/4 throttle on off / 180 degrees

Engine NEVER cut out or stalled during above steps. Was pretty rich and bogged slightly on throttle.

Now here's where the issues started ... On the 4th tank I started full throttle stabs (on & off) around the 6th or so pull it bogged bad and stalled out. Wouldn't fire right up right away but would start. Same thing again after around 6 pulls. Just called it quits at that point. Glow plug had some deposits on it from break in so I put a new one in thinking this may be why. Fired it up again and same deal. Took carb off and pulled apart and cleaned. Changed all o-rings and reset adjustments. Does the exact same thing. Look up "factory" settings and they are totally different than what I was using. My settings listed above were from an Adam Drake YouTube video on this motor. And the first 7 break in tanks it was like every other engine I have broken in, no running issues at all. The OS factory settings claim H 3 out from closed & L is flush. Those settings over 1.5 turns richer than the Drake video settings. On those settings the engine won't even run due to being to rich. Bearings , carb seat , slide boot, backing plate all sealed good so I don't think it's an air leak. I start digging around on this motor and I find about 2 other needle settings that are totally different. I'm just at a loss now lol. Again as mentioned using drakes settings with a caliber it runs perfect only going 3/4 throttle , it's when I go WOT it bogs and stalls like a rich stall. Yet if I lean it out it's like it's starving for fuel even though I'm going through 3/4 of a tank of fuel in about 4 minutes. And I'm using a 5oz truggy tank in a buggy.

jaka54

OK ! This is a car engine but as such it is run in the same way any other ABC,ABN or AAC engine.
First of all you should not count how many turns you have the high speed needle open, you just open it some turns (2-3) and then start the engine with the throttle set at idle and immediately the engine starts you give full throttle...and at the same time you set the full speed needle so that the engine runs slightly rich. Remember all setting when running in a glow engine should be done with the carb fully open!!!! I know that you probably do not have a propeller mounted so the engine can rew fairly high without a load, but still set it slightly rich! If you can I would advise to mount a propeller on it as needle settings would be easier that way. if so use a 7x4 or 7x5 APC prop.
On 80/20% Castor oil based fuel your engine would rew around 23000-25000 rpm. But you probably use nitro based fuel and synthetic oil, but never the less , running in process is the same!

1QwkSport2.5r

I will agree with what Jan said for the most part. Racers do not give one crap about how long their engine lasts because they’re often sponsored and do not pay for their engines. They want max performance right from the box, which you typically get from OS because they’re fitted quite loose and do not require much break-in. Ringless engines should always be run warm, and with oilier fuel to start with. Preheating the engine to 200°F to start with makes starting much easier, and allows a good needle setting to be had much sooner. After a brief 1-2 minute jog around to build some heat/maintain 200°F, stab the throttle and run it up. The conrod is what needs to break in, and rpm is what accomplishes this. This is where the oily fuel comes in. You need heat and rpm to get there, but most people run regular race fuel and just lean the settings to get the heat. The consequence is lack of lubrication.



180°F is too cold. 200°-220°F is proper. I use 1 gallon of custom blended fuel for breaking in my car engines.



Quart 1 = 10% nitro 15% oil (70/30 blend of castor to synthetic)

Quart 2 = 15% nitro 14% oil (70/30 blend of castor to synthetic)

Quart 3 = 20% nitro 13% oil (60/40 blend)

Quart 4 = 20% nitro 12% oil (60/40 blend)



Regular running fuel I use is 20% nitro 11% oil (70/30 blend). Sometimes I make slight changes to my oil ratios, but I always use FAR more castor than synthetic.



Here is a video of a junky RTR Traxxas 3.3 (modified) breaking in mounted in a Jato.