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Naturally Aspirated Performance ForumDiscussion of naturally-aspirated rotary performance. No Power Adders, only pure rotary power!
From the "12A" to the "RENESIS" and beyond.
You've always done so interesting and far-out things for as long as I've been here. So I look forward to what you're doing with this. I think I was able to follow all the photos so far, but I do have one question. In the first photo of Post #2, are those hole for you to make some kind of anchor for the epoxy or are they there for something else?
Exactly. I had epoxy come loose in an intake manifold once, so I anchor it whenever I can. I drilled a couple holes through with a counterbore for extra overkill, then pushed the epoxy (Quiksteel) through and then mooshed it over like a rivet. Then more on top for good measure.
The one that came loose, was that the 6-port manifold that you had converted to your T2 block? If so, I guess I missed that somehow. Did the broken piece get ingested?
No, it was a 6 port FC lower that I added epoxy to the primary port roofs to match up to a GSL-SE, since the -SE ports are lower. Maybe 2-3mm difference. The engine was pulled to install the 4 port engine I'd been building all summer, when I got around to disassembling it, besides a broken apex seal (still ran and had compression, it didn't FOD itself, just had one seal broken and looked like it was like that for a while) I noted that the epoxy in one of the ports was loose. Not fully fallen off yet, but touching it with my finger made it break away.
Not really. I cleaned up my bridge port's intermediate housing and found that it has .005" step wear. So i cleaned up the unported intermediate that came with the engine that donated the two end housings and found that a dime sized section right in the corner seal track in the combustion area rusted away to leave a deepish pit. So my only options for assembling the engine are questionable.
GSL-SE intermediate is required, as I need it for the injector bungs and for the engine mounting. Even if I had any 12A intermediates (I don't) they would leave me with no way of putting the engine in the car due to the FC front end.
I *could* deconvert it to FB front end and keep the FC struts with some Mazda3 ball joints, and I do have all the stuff to do this, but when I do this I want to get a steering box that has had a plastic pin locator failure, and splice a 2:1 steering quickener in it.
It's depressing and a continuation of all of the issues I had trying to get my '81 on the road. I am thinking more that the next step is a LS4, since you can easily find those engines for $600-700, and whatever TH350 I can find. I already have acquired a 2.75 gearset for the 9". I'll save all my remaining rotary stuff for the '81 and for the RX-3.
Oh man, that sucks! If I had some, I would surely send you a housing to get this thing together, but alas, I'm sort of parts-poor myself at the moment with the pre-'86 stuff. I can't wait to be able to start stockpiling whenever I am finances allow me to. Re-converting the front sounds like moving a couple steps back to take one forward. I mean, surely you converted for a reason in the first place.
So you're thinking of crossing over, huh? Well, definitely post whatever you do. You always have an audience with me. I mean, if I'm hearing you right, it makes sense.
On a separate note, I didn't realize you had an Rx-3 now. Congratulations on that.
The main problem with V8s is they don't accelerate worth a crap. They can make power but they aren't very drivable. I do like the idea of a 3400 or 3800 six, or a nice 2.4l Duratec, but any time I think about any of that, I end up spending way more money than buying a pair of new rotor housings and getting a set of side housings ground/lapped/rehardened. So, project stall.
The reason I converted is that I more or less ran out of strut housings. The snouts would bend a little and then there would be no way for the bearing to adjust properly. The FC has a much beefier spindle. The rest of the suspension is not as good, I think, as the roll center is way wrong for the rest of the chassis. Works fine with the ground-level rear roll center in the FC but not so much with a solid axle. I never really liked the way the FC front handles.
I made an interesting discovery today: Most of the apex seals in the engine were way overlong. The rotor housings both measure 3.148" and the shortest of the apex seals was 3.149, most were in the 3.150-152 range and one was 3.158! How did I screw that up? I spent a lot of quality time clearancing the lengths, clearly not enough!
Ironically the thing that got me motivated to work on this mess was discovering a 4 lug hub that will work on the suspension I want to slide under the RX-3...
That rust. Still not as bad as my bridge ported intermediate, so we're going with this one.
Stock GSL-SE primary ports. TOINY!!
Port taking shape.
The original "something completely different" was going to be a half bridge with the intermediate bridged (because It Was There) and the ends opened up to huge volume and stock untouched port windows. With that no longer possible, I'm going to do another one of my ports that are based on the theory of maximizing port energy. I tentatively call this the "peejay port". The opening line gets raised a lot, while the corner seal track line stays right where it is, so the "closing" line almost points at the center of the engine.
Why do I do this? Let's get the help of Rotor-san:
This is approzimately the point of fastest volume expansion. I want the port to be aimed more or less at the center of volume. Incidentally, MFR peripheral ports are aimed this way, and they work better than P-ports that angle down...
The aux ports in a 6 port are so high up that you get the same angle of attack flowing "straight in", which is the reason why I am not bothering to touch the port window.
This is approzimately the point of fastest volume expansion. I want the port to be aimed more or less at the center of volume. Incidentally, MFR peripheral ports are aimed this way, and they work better than P-ports that angle down...
The aux ports in a 6 port are so high up that you get the same angle of attack flowing "straight in", which is the reason why I am not bothering to touch the port window.
This actually makes sense to me ... I think. Is this sort of another take on how Mazda did the secondary runners in the REW - with that pronounced angle?
The REW ports go the opposite of ideal. I think Mazda only did what they did to make room for the turbos without putting a bad kink in the lower manifold like the FC had.
Not very much. I can't work in the garage for more than 15-20 minutes before the end of my left middle finger loses circulation and gets painful, which hurts progress and is bad for morale.
I had been planning on shifting the engine back about 75-80mm and using a Miata 1.6 driveshaft (same pinion flange as Series 3, but about 84mm-ish shorter) going so far as to start to design new carb linkage, figure a way of moving the shift tower on the trans forward, and acquiring two 1.6 drvieshafts for test purposes... but I don't like the idea of the flywheel's explosion plane being on the passenger compartment side of the firewall. I did the math and the weight shift would only be on the order of about 9-10lb off the front axle and onto the rear, so I stopped bothering.
I am, however, making completely new engine mounts (no pictures yet) and trying to center-line the drivetrain to try to eliminate any potential sources of driveline harmonics. This was made difficult because I had to first try to define the centerline of the car as compared to the rear axle. Can't just go by the strut towers and framerails because the nose of the car is shifted a bit - the car was heavily wrecked when I bought it and it's a bit tweaked.
i had thought about moving the engine back years ago, you could use the SA tail housing, in an FB body. flip the front crossmember backwards (probably won't work), and enjoy!
I am using the FC subframe... you might be able to use a front cover mount on the FC, but my idea was to string the engine mounts over to the steering box and idler arm mount locations.
Not very much. I can't work in the garage for more than 15-20 minutes before the end of my left middle finger loses circulation and gets painful, which hurts progress and is bad for morale.
Dr. Rudy Wells, maybe???
Oh, okay, so this is a complete revamp of the car, not just a new motor. I guess I'll wait and see what comes of it all.
As near as I can figure, this is centered. It is hard to tell because the car is bent. I ended up going back to the rear axle and triangulating fomr center points from there. Note that there is also a lot more engine to the left of center than to the right. I was centering off of the eccentric bolt, not the engine's center of mass.
Recent events had me more motivated to just make sure the car runs and is mobile, so I threw the old engine mounts back in with my last good FC mounts (after packing the left side with urethane adhesive) because it worked before, it should at least sort of work now. After fighting a bunch of just plain weird issues like my garage floor somehow containing an event horizon for dropped fasteners (literally, I could drop them on the ground, and they would just be GONE), missing fasteners, having to retap the threads in the intake manifold because they weren't quite 8x1.25, 8x1.0, 5/16NC *or* 5/16NF (they are 8x1.25 now), etc and etc, one weird thing after another... Heard it run for the first time at about 5:40pm, Eastern. Happy freaking Valentine's Day.
I should note that the odometer currently reads 251,666 miles Jeez, this car had 145k when I bought it.
Engine idles SMOOTH at 1000rpm for the three of four seconds of afterstart enrichment. Then it dies for lack of fuel. Apparently stock intake port timing will result in much higher VE for a given manifold vacuum, relative to a Group A spec bridge port. Who'd have thunk it?
I still don't have the cooling system installed yet, I wanted to get it together enough to hear run before I got to that point. Now that I know the engine has good compression and isn't a heaving mass of oil, I can put it the rest of the way back together and retune it. Ignition timing is currently 22 degrees locked, no split, triggered off of the trailing ignitor so that I can use the trailing vacuum can for the vacuum advance (ported, not manifold) because the trailing has twice the range of the leading. May revisit this. I'd LIKE to put an RX-8 wheel on it and run a gaggle of IGN-1As, but I've been unemployed for a bit and I'm starting a new job next week, so money is extremely tight right now.
The weather got cold again, and I'll be cranking out 45-50 hours a week at the new job, as well as doing side jobs on the weekends for a while (currently doing an engine replacement/upgrades on a 10vt Audi 200, next is complete hardlines and wiring harness for an interesting little short wheelbase Audi) so this is going back to the back burner for a while. First rallycross is scheduled to be late April and I'd love to make it.
Unfortunately I seem to have instigated power wars locally. The person I have to watch out for most is running an E36 rally car (not just a farking-around car) with an S52 engine swap, with upgrades, and he's not running dried out 5 year old tires either. When the money tree starts to bear fruit, I'll rebuild the bridge port engine with RX-8 internals and stick that in the RX-3, which is too rough to be restoration worthy but solid enough to be a good base for a competition vehicle.
Unfortunately I seem to have instigated power wars locally. The person I have to watch out for most is running an E36 rally car (not just a farking-around car) with an S52 engine swap, with upgrades, and he's not running dried out 5 year old tires either. When the money tree starts to bear fruit, I'll rebuild the bridge port engine with RX-8 internals and stick that in the RX-3, which is too rough to be restoration worthy but solid enough to be a good base for a competition vehicle.
there is a local shop that built an E30 with an S52 engine, and it is FAST. engine is not very reliable though, they did a 25 hour with the car and it took 3 engines to do it...
10-10-18, 07:08 PM
Jeez, this car had 145k when I bought it.