Please don't get your panties in a ruffle while reading this!

What part of the rebuild gives you the most compression? I'm ordering a jdm motor and going to rebuild it before I put it in. How would you do it?

 

http://www.rebuildingrotaryengines.com/

 

What are you asking exactly? Your compression needs to be above a certain value to ensure your chambers hold compression properly... Any less and you've failed the rebuild.
+1 for the link though! I rebuild my motor the same way I've rebuilt any motor, take it completely apart, inspect all parts to the value either set by the factory or service manual, put it back together using the suggested parts...?

 

That link is awesome! Thanks for that. I guess my question is what part of the motor is responsible for compression. Say your rotor housing have 90k on them and you do a rotor rebuild kit will the motor compression be above 100psi? If I had the side housin lapped will that help?

 

Well, there is no single part that is responsible for it. You must have good side-seals, apex-seals, corner-seals, rotor and rotor housing are all part of it. If any one of those goes bad, you'll lose your compression. If you do a rebuild kit properly, yes, you should have somewhere around 9 kg/cm2.

 

Apex seals and rotor housing chrome surface, above all else. Iron faces, corner seals and side seals render the rest of compression. Think of the apex seal, corner seal, and side seals as all forming a rectangular piston ring. The gaps/clearances where each seal meets the next form a collective "piston ring gap" just like you would have in a piston engine. The rotor housing surface and iron wall surfaces are similar to your cylinder bore. All these parts work together, but the apex seals and rotor housings being flat surfaces are the most important areas.

 

just buy all new rotor housing/irons

 

this guy is funny, he is buying a JDM engine with unknown condition, but then he will rebuild it before he uses it. Might as well just rebuild whatever **** u have right now.

Talk about waste of money and time, be a man and buy all new housings and plates whatever new, ceramics, whatever, u name it. There u go.

Responsible for compression? Hah! So you're telling me u just want compression and nothing else? wow. the answer is the whole short block.

 

Yeah, sure...lets build a block from all new parts. We can reuse the gears and rotors, but the rest...new, definitely. Let me drop 4G's plus assembly labor on a block for a car that in all likelihood is worth 2-3 grand running and complete. Okay.

 

Its really not that odd. He's probably sick of his slow NA, looking to pick up a jspec turbo engine. If that's the case, then rebuilding the motor he has now would be a bigger waste of time and money when he realizes it's still a slow NA, even with fresh internals.
And at least he's already made the assumption that the JDM engine will need to be disassembled and rebuild. No warranties or compression tests from the distributors. Half of them are just 300lb paper weights.