The DADDY of all DIY rebuild threads...
11-09-07, 05:39 PM
#26
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.
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.
11-09-07, 05:59 PM
#28
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.
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.
11-09-07, 07:55 PM
#36
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11-09-07, 08:16 PM
#38
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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.
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.
11-09-07, 08:16 PM
#39
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.
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.
11-09-07, 08:18 PM
#40
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.
11-09-07, 08:38 PM
#42
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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.
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.
-Rob
11-09-07, 08:46 PM
#43
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.
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.
11-09-07, 09:27 PM
#44
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!
Thanks again for all of the help!
11-09-07, 10:18 PM
#45
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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.
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.
Last edited by Boostmaniac; 11-09-07 at 10:30 PM.
11-10-07, 02:12 AM
#50
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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
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