Some of you may remember us (my kids and me) for buying an NA Miata and getting it going as a first car (https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/our-first-car-resurrecting-the-answer/133847/page1/). Well, now the 11 year old son Mark from that thread has just turned 15 and has his permit. The daughter has completely claimed the Miata, so we needed another vehicle. So, Mark decided that he wanted to learn about rotary engines, so we now have a 2005 RX-8 with a tired engine. We have managed to pull the engine and completely disassemble it with the typical youtube videos and random forum posts, but now that we need to figure out what to replace and what to do to prep the pieces for rebuild, we're struggling to find anything coherent. For a reciprocating engine guy, the basic parts look to be in really good shape, but we are trying to decide what things we have to and/or should replace and what prep work to do on the parts we're keeping (iron faces, mostly). Do we replace the water and oil pumps because it's apart? Or is that a waste of money?
Can anyone recommend a reasonably reliable book/forum thread/online personality we can use to figure this out?
j_tso
Reader
4/16/21 5:55 p.m.
CarThrottle's RX-8 review and rebuild, their video production is better than other youtubers I've seen, less annoying music and editing.
I'd replace the water pump. The oil pumps are pretty robust and should be good unless the pump rotors look damaged, at least that's the way it is for RX-7s.
mdshaw
Reader
4/16/21 6:05 p.m.
Look it over really well, clean it up, box it up, put the motor up for sale & do a K24A swap. 
Your son has learned the uniqueness of a Renesis, now he can learn how easy it is to have a reliable motor & add a turbo for 400hp fun.
In reply to j_tso :
That assembly video is really good. Thanks.
Any thoughts on what to do with the shiny surfaces on the irons? Just run it? Or scuff it somehow?
In reply to mdshaw :
We will engine swap something sometime, but this time it's just a stock rebuild. Someday we'll bring something to the challenge, and that will likely be swapped. I do appreciate the sentiment, though. I'm not used to buying tools because "we'll need it when we do this again on this engine".
The rx8 engines are rough. Even a rebuild may only last between 50 to 100k miles.
I'm guessing you need new housings and all new seals. Thats why most of the rx8s need an engine. That's like a 3k do it yourself bill!
There is a rebuild video from Atkins rotary that is like 25$. It walks you through step by step on how to rebuild the engine, what to look for, and how to measure everything.
I'm gonna guess the housings have chrome flaked off of them.
I am Mark, pkingham's son, the driver of the car. I was looking at the rotor housing, and the chrome looks like it is undamaged. But there is some black stuff near the lower spark plug hole, I did a little scrubbing and it did not come off. Is this something that I should worry about?
mdshaw
Reader
4/16/21 9:06 p.m.
After it's done, a big ignition upgrade is the LS kit.
I understand not doing the K swap but after seeing what a friend of my son went through with his RX8, I learned I didn't want one with the stock engine. Great car otherwise.
I was browsing auto tempest the other night & there are a bunch with bad motors or "non starting". A friend wants a sedan with a useable back seat for his kids so an RX8 K24A2 turbo 6 speed would be an awesome family sport sedan. I've also been reading about self & shop rebuilds gone wrong & seems like a risky endeavor.
Your best source of info is going to be the original rotary shops and forums.
Mazdatrix has a good m, thorough rebuild video:
https://www.mazdatrix.com/product/video-engine-rebuild-how-to-rebuild/
Pineapple racing has some good tools:
https://www.pineappleracing.com/toolsandequipment.aspx
rx8club and RX7club are good forums with archived knowledge. Search button is your friend to learn from past threads. Then post for specific questions.
There is nothing on a rotary that requires scuffing
Vajingo
HalfDork
4/16/21 10:48 p.m.
j_tso
Reader
4/17/21 12:14 a.m.
mkingham said:
I am Mark, pkingham's son, the driver of the car. I was looking at the rotor housing, and the chrome looks like it is undamaged. But there is some black stuff near the lower spark plug hole, I did a little scrubbing and it did not come off. Is this something that I should worry about?
Some dark discoloration is normal. Housing combustion surface shouldn't need more than a good wipe down with solvent like lacquer thinner. Top priority with condition of is smoothness of the chrome. Small scratches may be okay, but anything that can catch a finger nail is usually no good.
There are factory manuals for Mazda rotary cars at foxed.ca , there you'll find how to check the side housings for flatness.
