Beautifully and concisely written, Mr. Landers.

Even though I've never seen the inside of a rotary in person, your description of procedures coupled with the pictures certainly removed much of the mystique and uncertainty.
Not that I plan on tearing into a motor anytime soon- at this stage of my life I'm content to let specialists have their way- but it's nice to be semi-conversant with the process anyway.

 

You're welcome to write whatever code you feel needs to be put in place and I can upload it per your instructions

 

Just a quick question about lapping the housings. I talked to people, cant remember their names now, at racing beat a while back and they said they never noticed any signifigantly faster wear with lapped housing that were not nitrided over new stock housings.
The housings that came in that were lapped, do you remember how many miles were on the engines when they came in?
The reason I ask is because I ended up getting the housings lapped and was going to get them nitrided but racing beat talked me out of it so now im curious.

 

What about if I just save the webpage on my computer?

 

Thanks, I like how you show what is considered a good re-usable part and what needs to be replaced. link is bookmarked and i'm subscribed to this thread

 

GOBSTOPPERS!!!

 

Did that car suck in a leaf and then pop haha.

Great write up bud. Noted and will be printed.

Anyone know why its 99% of the time, the rear rotor that blows?

 

pre-ignition?????

 

Or good olde ctrl+c ctrl+v

 

Great stuff you cocky SOB.

This is greatly appreciated. Thanks.

 

i've noticed that too. kinda funny. im just guessing it has something to do with excess heat. it just has to be i mean there's practically no difference between the components in the rear and the ones in the front. i know the rear housing is the last stop for coolant to cool so by then its already heated up by the front housing and so cooling efficiency is low and its sandwiched between the rest of the engine and the trans further makes cooling difficult but this is just speculation so far. sorry for thread jacking. lol

 

Fantastic writeup! Just curious, how long did it take you to complete it?


Thanks.

 

Kevin, I don't frequent the FC section much, but I saw this and had to give it a click.

Excellent job with the write-up. You obviously took quite a bit of time and effort to create this, and I'm sure that it will help many people in the future.

This is one of the primary reasons that I love the RX-7 community, as there are a large number of people that go above-and-beyond to help others. You don't find that in many other circles.

Godspeed,
-Rob


General theory is that this is primarily attributed to the difference in LIM runner lengths (although I don't think this has ever been 100% confirmed through scientific testing). Hence the creation of the Xcessive/GroundZero equal-length LIM.

 

Wow, an actual useful post from Toyo Kogyo.

It took me about a week to do this work, as usual for one engine job. I just snapped pics and took notes along the way to help with the writeup later. As for doing the writeup text to match the pics, well that took about a week, working 1-2 hours daily. As for putting the pics in the writeup, that took me most of today.

As far as the lapped iron debate, most of the failed engines/irons had <10k on them. In fact, I just had a conversation with a small shop owner who was talking to me about doing some work. He was telling me of a conversation he had with mazdatrix' engine builder who actually recommended against lapping the irons if at all possible for the same reasons I mentioned. Now, this is secondhand information so don't quote me on that, but my stance remains the same...the risk and cost isn't worth whatever you hope to gain.

 

Oh, the rear rotor. Usually it blows even in NA engines where airflow is not that important, so the rear runner being a straighter path than the front runner is only part of the equation. More than anything, the rear rotor gets preheated oil and coolant after the front of the engine and so it just makes sense that temps and friction will be slightly higher on a localized basis in the rear. Over tens of thousands of miles and years, this takes its toll.

 

A true testament to the Rotary Resurrection name. Well said.

 

Good to know! I guess I was coming at it from the FD point, where long term wear isn't so much of an issue

I also agree with your opinion on lapping. I would never recommend using an iron that has been freshly lapped. However, I have had fairly decent success with lapping followed by flame-hardening the surface. This adds an extra step and cost, but is a method that could potentially save an out-of-spec iron from the scrap pile.

-Rob

 

but, as far as lapping...for a set of 3 irons, 4 faces, is usually $400-500. Plus shipping both ways of at least $100. Then whatever extra processes you add, such as nitriding, cryo, heat treating, etc.

All the while a man can get a set of 30k mile jspec irons for 3-400 bucks with 2 or 3 thousandths of inconsequential wear, or you could probably get a set of 3 brand new in the box from mazdaspeed for like 1100 bucks. It just seems like the long way around for no gain, in my eyes.

 

Truly a fantastic writeup. I am actually in the middle of rebuilding my engine at the moment (currently in the cleaning stage) and this is some great info to help me. I already knew most of it from rebuild videos, but it went a long way to ease my mind. I knew that small step wear and minor chrome flaking was fine (mostly from Kevin telling me so...) but seeing all of this written up goes a long way to make me feel better about the parts I am using.

Thanks again for all of the help!

 

You sir are a god.

Also somewhat related but has nothing to do with NA motors, on a TII motor, the ECU cuts fuel to the rear rotor when the boost goes too high if you don't have a fuel cut defenser.

Why they just didn't cut ignition I'll never know.

 

I also say we sticky this immediately. This is WAY to much info to be lost somewhere in the forum.

 

Especially now that everything older than a day disappears....
Edit: Just fixed it. They changed the forum defaults, apparently.

 

I'd just like to take the opportunity to say thank you to all of you great members of this club that make this all possible. So Thanks for the info guys.

 

give u mad props for all that work
this needs to be sticky

 

sick props for this i was just beginning to feel overwhelmed by planning my rotary swap and trying to figure out exactly what i needed to do, what was worrying me the most was the rebuild as i was just looking at parts on mazdatrix. The first thing that struck me like a phonebook to the face was the fact that studs for the motor is 450 bucks or so. Made me feel like i got hit by a truck and then had a hooker steal my wallet.

This makes it so much easier for me because now when i get the motor (i used to be a piston head and still am i've built tons of piston motors but only just recently decided that rotary was the best bang for the buck) ill know exactly what i need to pay attention to so that i can know what parts i can salvage and what ones absolutely need to be replaced. I was not looking forward to this again until i started reading this thread.

THANK YOU, you turned the lightbulb on in my head lol. Now i know i will have no problems tearing into the motor when i get it, that and sidepex is around the corner from my house =] so i got plenty of things to use as references now

+1 for sticky