Joined: 12 Oct 2005
|Posted: Thu Oct 13, 2005 6:43 am Post subject: Hyper .21 8-Port Break-In Procedure
|Let's see, when I run in a new engine.
First I rinse out the engine case. Then install the engine in what ever chassis it's going in. I leave the plug out, fill the tank with fresh fuel and put about 15 drops of Marvel in the engine. I set the carb fully open and put a rag over the head. I then spin the engine over on the starter box till about 1/2 the tank of fuel is through the engine. Then I install the plug and close down the carb.
I fire the engine and let it fast idle for the first half tank leaning the lowend to get engine temp up to 180-200 quickly. Shut down and let cool 20 minuets. Restart and fast idle for another half tank. I might add here that when first running in a new engine I always run the tank down to half and then refill it to prevent the engine from leaning due to tank pressure drop.
After 1 full tank I drive the car around on pavement for half tank at a time and let cool 20 minuets in between. I keep engine temp in the 200-220 range. After 2 tanks of moderate throttle I run the next 3-4 tanks back and forth in straight line sprints with occassional 2 second full throttle blips.
Once thats done I tune for performance as mentioned in the Pit Tips section. This part I do on the track where rolling resistance is normal. I warm up the engine for 3-4 minuets then I start making high speed straight line passes of around 60-80 feet. I make 2 passes wide open and listen to the engine. After each 2 passes I lean the topend 1 hour, make 2 more passes and lean another hour. At some point the engine will reach a max where leaning further will only cause temps to rise with no increase in engine speed. At that point I richen the HSN back up 1/8th turn.
Then I tune the LSN. Again I warm up the engine for several minuets and then make 2-3 high speed passes. Then I stop the car and do a mental 5 count and pin the throttle. I lean the LSN 1-2 hours at a time untill the engine will set at idle after WOT for a 5 count and take sudden full throttle input without hesitation.
After all that hassle and riggamaroll I start running the car around the track as I would race it. I run 3-4 tanks in a row and monitor engine temps to make final adjustments. After a about a half gallon like this I run the snot out of it.
Note that this is how I setup and tune engines for around 95% performance. This is for flatout hardcore racing. If you are going to just be bashing around or occasssionaly club racing you probably want to run the engine a little richer on both the LSN and HSN's for longer engine life.
This is just the way I run in my engines, and since you asked, here it be.
Written by Jim Newman