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Hi - I have no idea why I can't start a new thread, so it looks like I'm hijacking this one.
I have an '04 (Series 1) automatic that has recently undergone an engine/transmission change. The swap was completed by some guys in high school before I bought it, and I have no idea what was put in. The car performs pretty badly, no power at low rpm, late shifts, etc.
I did a compression test and the engine seems to be ok, so here's my question:
If I suspect that a series 2 engine/trans (6 speed) was put in instead of the correct replacement, how can I tell the difference externally? Or do I just drive the thing and count shifts? If it's not shifting right, I'm not sure I'll get an accurate count.
the s1 autos in 2004-5 had a 4 port engine and iirc a 4spd auto trans. all 8s after 05 had a 6 port engine regardless of transmission. the ecu from an 04-05 auto is different than 06+ autos and making a s2 09+ engine and trans would be a very hard task. can you post a pic of the engine? the upper intake manifold is a dead give away on weather its a 4 port or 6 port engine. btw im less than an hour from bangor
I see a big (Yooooge) difference in the output shaft housing. I'm gonna use that as a guide, since looking for that stamp will be pretty difficult. My first step will be to drop the transmission pan and change the filter and fluid. I just wanted to be totally sure I got the correct fluid. I've heard '04 and '05 use Dexron III, while the 6-speed autos use a different fluid altogether.
this has peaked my curiosity. please post some pictures of your engine bay. A 6 port engine will run with the 4AT ECU but you won't get much more over 4k RPM. A dead giveaway (once we verify you actually have a 6 port engine) will be taking a look at the number of ports/plugs going into your ECU.
I do not think a 6 speed transmission / bell housing will line up with the 4 port motor. There is at least one bolt that will not match up if memory serves correctly.
And there is the whole TCM issue. I doubt the 6 speed auto TCM would talk with the 4AT ECU, but I can't say for certain. Not even sure if it has ever been tried.
Before we go too crazy, I should tell you I'm a noob. I got the car from a kid who had just graduated high school. He and his buddies did the engine swap, and I can't get much info from him as to why it runs like crap.
All I know is that he bought a used engine/trans combo when his engine took a dump. As for me, I've just always wanted a rotary to tinker with. I can do just about anything with a piston-driven motor, but my only experience with rotarys is the fact that I built one of those 'visible wankel engine' models when I was a kid. Since then, I've always wanted one.
Pretty sure I have the 4-port, because I remember a lot of room in that one part under the hood. I'm at work and the car's at home. The car is terrible off the line, almost to the point of stalling. Compression was done using a standard piston compression tester with the valve removed and video'd in slow-motion, as seen in this video -
I copied the spreadsheet from his site and got between 6.5 and 6.7, meaning it is going, but should still run decently.
My symptoms are that it seems like the transmission wants to stall the engine when it's engaged, the shifts are late, and when I switch to manual mode, none of the manual shift functions seem to work - like it's still in 'D'.
tbh, an 04 auto 8 is the least desirable and most expensive to rebuild/replace a bad engine. its also the slowest and least fun to drive. you need a rotary specific compression test to determine engine health. if you havent already please read the new owners threads a few times. pics of under the hood would really help us tell you what you are working with
It looks about as stock as it gets... beyond a couple oddities (zip tie on your master brake cylinder - guessing the cap is broke) and that red clip on your MAF wires (1st picture).
Any idea on the age of your coils and plugs? I'd start there.
A fun exercise may be running some seafoam through the lower intake manifold nipples / ports while maintaining about 1500-2000 RPM (2nd picture for reference). At the least you'll generate a bunch of smoke for your neighbors. At most, it'll get some carbon off the rotors / housing.
The vacuum chamber for your SSV has a bunch of oil on it (2nd and last pictures). Maybe from oil spillage. While it wouldn't be the first thing I'd go after, your SSV may need a good cleaning. All SSVs typically do.
I wouldn't worry much about the transmission at this point although a flush is always a good idea. If you're going that route you might as well replace the gear oil in the differential too.
While using the paddle shifters you should be able to cycle through the 4 gears and visibly see them indicated on your speedometer.
Ah- the hell with it. I just sent Atkins Rotary a chunk of money and I'm taking the motor out. Going to disassemble both the 40K useable engine and the 130K bad compression engine and Frankenstein all the best parts together, along with new apex, corner, and side seals. I figure this way I will know everything there is to know about my specific car and engine. And yes, I bought the AT filter that everyone said didn't exist.
I've seen used housings and plates on EBay, and they all have similar wear patterns in them. Would having these re-surfaced at a machine shop be beneficial, or would that remove the 'nitride coating' I'm hearing so much about? I've heard other people say just get the best looking, smoothest parts and do a light sanding.
Also gonna thoroughly clean the ports. No radical increases there, but I am going to make sure every square millimeter is shiny and silvery. Everyone I talk to about porting a 4-port AT says don't bother, because there's too much I can mess up for a potential 10Hp increase. Thoughts?
Also gonna thoroughly clean the ports. No radical increases there, but I am going to make sure every square millimeter is shiny and silvery. Everyone I talk to about porting a 4-port AT says don't bother, because there's too much I can mess up for a potential 10Hp increase. Thoughts?
I personally would save the money and then explore a turbocharged solution. You don't have to go crazy with the peak power, just having more torque in the lower RPM band would have been a great improvement. I don't know how much the 4AT will like that, though.
IIRC there was a thread where someone explored turbocharging the 4-port engines. Never got into it to see what happened, though.
Over the course of 7 years I went through 3 turbos on my four port. GregSki, trust us when we tell you it is not worth the investment.
If you have an ADA type situation then I understand the need for an automatic but you haven't mentioned anything like that up to this point. Even under those circumstances I'd recommend the 6AT.
The 4AT is not worth the investment at this point materially. Hell, all 8s are close to being at that point. it is going to suck you dry, mark my words.
Over the course of 7 years I went through 3 turbos on my four port. GregSki, trust us when we tell you it is not worth the investment.
If you have an ADA type situation then I understand the need for an automatic but you haven't mentioned anything like that up to this point. Even under those circumstances I'd recommend the 6AT.
The 4AT is not worth the investment at this point materially. Hell, all 8s are close to being at that point. it is going to suck you dry, mark my words.
COOL! At my age, I only get that on my birthday! Srsly tho, it's my garage, my choice😁. Just something I've always wanted, and now got. Maybe I will fix and sell for a 6AT that needs my loving touch one day, but for today I'm infatuated with the rotary itself.
Well damn. I just received my engine closing kit from Atkins. Now that I hear all the chatter about their business practices, I'm skeptical. It is what it is, and I've already got the motor out. I hope these apex and corner seals are good.
It'll be a great hands on learning experience. You should be ok, but imo the quality it's as high as oem. Plenty of people still use them for odd ins and outs
Haven't finished disassembling yet, as I gotta squeeze this in between work, sleep, house chores, and keeping the wife happy.
Got a possibly dumb question - my apex seals came in 2 pieces. I think I remember hearing someone somewhere say I can use crazy glue to put them together for easier install.
What might you do in my position? Depending on what I end up doing I may have a spare parts car, chassis, or all of what you read here may be available.
Any feedback is appreciated.
I own the following cars and I’m working on just what to do with them:
Red 2004 MT Rx8 – foreground – (Transmission Rebuilt; Engine Damage (rotors/housings ruined) and cannot be rebuilt);
Red 2004 AT Rx8 – background – (Complete car; low compression - cranks and will not start );
04 MT Foreground; 04 AT Background. Body/interior is better on AT, but MT is mechanically sound (except motor).
Blue 2005 MT Rx8 – Blue – (Engine Cooked and cannot be rebuilt but otherwise complete);
2008 MT (Engine Only. In Process of Rebuild. Had low compression and was torn down for rebuild while still running. Bought Engine with Rebuild Parts for $700.00)
2008 MT Rebuilt Engine: Install to 2004/2005 MT:
This should be a straight-forward repair as I have all parts to install the rebuilt motor to the existing MT vehicle; just have to choose which car gets the motor. If I go this direction, I will still have one complete MT car without an engine and the AT car with non-working motor. Thoughts on what to do with these cars?
2008 MT Rebuilt Engine: Install to 2004 AT:
I read your conversion post on the forum and would probably use the 2005 MT car for all donor parts. If so I would have a functional MT in good condition, one MT rolling chassis, and one MT ready for rebuilt engine.
4-port 4-speed AT to 6-port 6-speed AT
There is a wrecked 06’ Rx8 (attached photo) with 6-port engine and 6-speed transmission at one of the salvage yards not far from me and I’m wondering if you know of a good resource for info about converting the 2004 AT to a later model AT with 6-port engine and 6-speed transmission. Presuming the salvage parts are not damaged I could obtain the motor, trans, and electronics for $1,000.00; I’m skeptical about the engine because it may have as many as 153k miles but was obviously running (strong) at the time of the accident. If I can swap the 2006 AT guts into the 2004 AT car, I would have the left over 4-port non-running engine and 4-speed transmission that could be sold or scrapped.
To swap, I believe I would need the following parts from the wrecked car:
Motor
PCM (Computer)
Keyless Unit (Security/Ignition Key Module)
Transmission
TCM (Transmission Control Module)
? Instrument Cluster
Differences likely?
? Steering Wheel / AT Paddles?
Differences likely?
Other Necessities from the Wrecked Car?
Once I take what I need from the car, they will probably crush or scrap it so I probably have only one opportunity to harvest parts.
07-23-2020, 12:25 PM
