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-   -   Mugen Ninja JX21 Question (https://www.rctech.net/forum/nitro-off-road/435513-mugen-ninja-jx21-question.html)

GulfstreamIVCap 09-17-2010 10:12 AM

Mugen Ninja JX21 Question
 
Folks,

Appologize for the newbie question. I'm new to RC Cars and have finally completed my Mugen MBX6T M-Spec. The engine I'm using is the Mugen Ninja JX21. I read the engine break-in bible, and plan to follow this method, but not sure about how to determine/find BDC.

Can anyone point me in the right direction?

Thanks,

jpalessi 09-17-2010 10:21 AM


Originally Posted by GulfstreamIVCap (Post 7951719)
Folks,

Appologize for the newbie question. I'm new to RC Cars and have finally completed my Mugen MBX6T M-Spec. The engine I'm using is the Mugen Ninja JX21. I read the engine break-in bible, and plan to follow this method, but not sure about how to determine/find BDC.

Can anyone point me in the right direction?

Thanks,

(BDC) stands for bottom dead center of the rotating assembly IE: piston, rod, crank. BDC is 180* from top dead center. when you spin your flywheel over by hand you can feel the compression as the piston moves up towards TDC. You can feel/put your piston at BDC by simply feeling the rotating assembly by spinning your flywheel till you feel it at BDC. no resistance at BDC. understand? you should always put your piston at BDC after turning your engine off. this will help with the life of the piston and liner.

AZRC4Me 09-17-2010 10:24 AM

You can do one of two things-take the glow plug out and move the flywheel with your fingers while watching the piston. Or, you can take the backplate off the engine and visually see the piston at BDC. Either way, once you find it, place a mark on the flywheel for reference. BDC is bottom dead center and is the lowest point in the cylinder the piston is at during its stroke.

Alan D. 09-17-2010 10:35 AM

Joe's way is soooooo much easier.

GulfstreamIVCap 09-17-2010 10:52 AM

Thanks guys!

bigjayjay1 09-17-2010 11:41 AM


Originally Posted by AZRC4Me (Post 7951764)
You can do one of two things-take the glow plug out and move the flywheel with your fingers while watching the piston. Or, you can take the backplate off the engine and visually see the piston at BDC. Either way, once you find it, place a mark on the flywheel for reference. BDC is bottom dead center and is the lowest point in the cylinder the piston is at during its stroke.

Dam your making it hard

AZRC4Me 09-17-2010 01:31 PM

Really? Taking a glow plug out is hard? Plus, I figured for a newbie, he may not know just by feel, but after he gets used to playing with his motor and using a visual indicator of where bdc is, it'd be easier for him.

jpalessi 09-17-2010 01:38 PM


Originally Posted by AZRC4Me (Post 7952357)
Really? Taking a glow plug out is hard? Plus, I figured for a newbie, he may not know just by feel, but after he gets used to playing with his motor and using a visual indicator of where bdc is, it'd be easier for him.

I liked your idea of marking the flywheel... that would help for sure. ;)

AZRC4Me 09-17-2010 02:09 PM

That really helped me out initially but it becomes a feel thing overtime for sure. :D


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