Chummins112

Well my thought was correct, I pulled the engine back out and swapped the flywheel/ and rear case with the stator and CKP etc. put everything together went to check spark and got my hand zapped pretty good! Lol. so if anyone ever else wants to do it, you will need to swap main shafts and the rear case etc off the 520 into the 420. I also had to swap the temp sensor. I took it for a 30 min rip and it was running very rich at the start and stalling a little at idle, but at the end it started to clear up so I’m assuming the oxygen sensor and ecm are learning for the smaller piston, but over all runs good! maybe the world’s first 420 rubicon?!?

Ah yes, I had a suspicion, darn should’ve done my research since I already was in there to swap the main shafts since the 420s was too short! Guess I learned my lesson today. thank you for the fast response

Hello everyone, first post, might have a new topic for you guys today, I have a 2020 rubicon foot shift that threw a rod and completely destroyed the motor. The cost of the parts alone would have been half of what I paid so I chose to swap in a 2012 rancher 420 motor that ran good. Everything is hooked up I have no codes, when I turn key on fuel pump turns on and I hear the throttle body do it’s thing. BUT I have no spark, it will spark once and a while but not consistent. My question is do I need to put the stator and pulse sensor out of the 520 into the 420? The cases are the exact same just would like to avoid pulling the engine out again. Also all the wires of the stator matched perfectly to the 520s harness. I do not have a peak VR but I can require one. I don’t see the pulse sensors being different between the 2 motors.