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Hello rotorhead, this is rotorhead - remember me from several forums back and crap? Got bored enough at work to be convinced to sign up after IRC bardgering; I'll probably start my own thread for crap I've been messing with too. Just wanted to say that I'm kinda jealous of your workshop, but definitely not jealous of you working around all that stock FD wiring. Race FBs are so much simpler.
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Jan 28, 2016 20:59
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| # ¿ May 10, 2024 04:34 |
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I really do have to wonder how the R6725s work vs the BUR9EQs; I know the R6725s work great for what I'm doing, as long as they don't foul, but if I had to buy more I'd be annoyed. And some day I still want to play with surface gap plugs again (funny story; basically when you cut a housing's spark plug holes to bring a plug in closer as an experiment, make it obvious on the outside it's cut; whoops) ... sigh, someone buy me an engine dyno. 
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Jan 29, 2016 17:07
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Assume you checked for warping and all... huh. Those don't look that bad, really. What would it take to get some junk parts after tax refunds come in? I'm looking at starting an engine program and don't have any T2 or FD end irons to flowbench (I'm going to just assume the 12A center irons can be ported more and not bother on those)
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Jan 30, 2016 16:45
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Nice, Xcessive LIM on that sucker too. I'm going to have to do a 3 rotor at some point, but may just cheap out and do "short crank" style one. Don't need the thick iron if you're doing peripheral ports, heh heh.
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Jan 31, 2016 04:56
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The lower intake manifold is aftermarket; they reworked the runners for better flow balance and an extra injector spot per rotor (for a total of 3 per rotor). There's also a version with shorter runners for better high RPM power, but this doesn't look like that one.
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Jan 31, 2016 14:40
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My lust for FDs was dulled when I found out I don't fit in them. At least not the real ones... maybe I'll build a tube chassis one someday.
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Feb 4, 2016 17:55
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You got a good housing out of a random engine? Wow, working on 12As has made me a pessimist. I should just start machining 13B housings down to 12A size like Atkins does... (or stop running 12As; I'm almost out of rotors anyway)
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Feb 8, 2016 14:21
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88h88 posted:Seeing as this appears to be the home of rotary experts, I'm looking at buying an FB this year because I just love the things. The most common unobvious rust place is the inner wheel wells; you can check by taking out the storage bins in rear. Unless you like rust repair, walk away from one rusted there. They use recirculating ball steering, and it just plain will have more play than a rack and pinion setup. Some of this can be adjusted out, some can't. If you start modifying stuff, the rear suspension has issues - at the very least, never put harder bushings in both the upper and lower links or you'll have a bad time. Really good solutions for the rear suspension exist but I don't know if they're still sold and they're oriented towards road racing. For that matter, there's a big gap in modification after "strut inserts, shocks, springs, bars"; thanks to the front strut design, there's not a lot of options for good coilovers without machining. Cars with rear disc brakes are the ones you want - in addition to disc brakes they also usually will have limited slips. The older naturally aspirated rotaries have a lot longer lifespan than FDs are reputed to, but most FBs are 12As, and 12A parts are mostly no longer available - so there's a little bit of a crapshoot. On the other hand, if you're comfortable with a bit of wrenching, an FC 13B bolts in with very little effort and a couple parts that Racing Beat sells, and even an NA 13B is pretty fun in these cars - there's options to put a carb on them or you can use some sort of standalone EFI, depending on comfort level. That's it for off the top of my head. They're fun little cars (I have a lot of them) but as you'd expect, they do have a bunch of stuff relating to the fact that they're all at least 30 years old.
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Feb 9, 2016 12:30
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88h88 posted:And that's the issue. Due to them being such a bloody rarity over here it's the engine that's stopping me going and grabbing one right now. I'd dearly love an FB, they're beautiful little cars but the spinny triangles and lack thereof of parts and such is putting me off a bit. I mean the rotary is a reason I kinda want one too but I don't really want to be paying out what the car's worth if it decides to poo poo the bed. All depends on what you're going for, really. I mean, an NA 13B can last as long as any other Japanese engine if you take care of its quirks (don't overheat, premix or make sure the oil injection is working). If you put value on having a quirky classic Japanese sports car that can last a good long while, figuring out an engine once and just driving isn't that much of a cost, especially given as how FBs (at least where I'm at) are available cheaply. If you're looking at it in terms of what value some future owner would put on the car, well, I won't try to argue, except to say that fixing up most older cars doesn't make sense either. *quick edit* I should note that I had a couple daily driven FBs, one of which I bought from a junkyard and just drove. Additionally, one of the cars I got had something like 270k miles on the odometer. So it's not like 12As are automatically going to be dead, just it's more cost effective to go with a newer 13B than trying to rebuild a 12A. ShittyPostmakerPro posted:Erm...what the gently caress?! Yeah, basically that. Otherwise there would be no steering feedback whatsoever, which would suck. Well, suck even worse than recirculating ball steering. Rack and pinion conversions for FBs are kind of a holy grail for a lot of owners, but there's not many good ones out there. mekilljoydammit fucked around with this message at 14:25 on Feb 9, 2016 |
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Feb 9, 2016 14:22
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You guys are making me want to get one of my FBs going for this summer instead of working on the race car ... FB. Darnit.
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Feb 9, 2016 20:07
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It's too bad it's hard from an emissions standpoint to swap an earlier 13B into the RX-8; every other aspect should be more or less cake, but because it's an OBD2 chassis, doing it as a street car is problematic.
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Feb 10, 2016 18:44
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BloodBag posted:Wouldn't a renesis in an NC be a more...interesting use for that motor? I always thought so, but a lot of people bitch because the renesis isn't boosted. "Oh no," they cry, "real rotaries are turbocharged!" ignoring most of everything sold before '93. Sure the renesis has its issues, but it makes enough power to be fun. Personally though, I'm looking at going streetport 13B into NA, due to emissions laws ... well, and the number of streetported 13B parts I have handy.
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Feb 10, 2016 22:32
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CAT INTERCEPTOR posted:It's not a bad motor as per say, how Mazda did emission and cold start are the problems. As I understand, the Renesis is actually the best 13B esp if you want boooooost and you can address the issues reasonably easily, albeit illegally. It's a pretty good NA engine for near its stock power output or a bit more with a standalone and some tuning, as long as you're not roadracing. The way the exhaust ports work, the spring behind the side seals are exposed to a lot more heat transfer from exhaust gases, and if run really hard for a while they give up. And because the exhaust flow is a lot less sudden than the older style exhaust ports, they won't spool turbos the same way. And there's a water jacket right near the exhaust ports, so you can't make much more power without doing weird things like having the old *and* new style exhaust ports by mixing and matching parts.
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Feb 10, 2016 23:00
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From hearing from pro teams back in the day, and club racers more recently, if you run the things at 10/10ths on a track, the side seal springs lose their temper and go off in about 50 hours (IIRC). This isn't really that bad, as the springs are pretty cheap, but it's a failure mode the older 13Bs didn't have - I've been looking at everything from the point of view of building a roadrace car lately, and given one engine option that I have to refresh more often, I'm going the other way. Think of it this way - assume you're starting with a good engine and you swap it into something, meaning standalone, and fixing the conservative oiling. Now you have something where you can basically overlay the graph with an F20C and match it, except smaller and lighter (I have scaled 13Bs at 250, supposedly the Renesis is 275 dressed and the F20C is 325 in similar condition) and that bolts to any transmission that bolts to a rotary. If I didn't have a bunch of hairy balls out ported 13B parts sitting around (well, and I like building engines) I'd look for one for street use to drop in a Miata. The older style 13Bs have more potential in a radical NA form, or when boosted, but the Renesis fills a pretty nice niche.
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Feb 11, 2016 02:22
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NitroSpazzz posted:poo poo for some reason I thought those things were a lot lighter than that Well, there's a lot of cast iron. If you have rear end wiping money, the racing beat aluminum side plates drop about 40 pounds off the engine in total. Still, 250-275 pounds isn't bad. The 250 pound one I scaled was complete from pulleys to clutch (racing clutch and flywheel but whatever) minus the carburetor but including oil. Given that one was a peripheral port motor, 300+ at the flywheel is possible. the spyder posted:
 I honestly quite like my dad's RX-8, though I can see the argument that at its stock curb weight the Renesis may not be the best engine for it. In something lighter though, I really don't see much wrong with the Renesis.
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Feb 11, 2016 14:28
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Oh well that makes it easy to rule them out for a stupid project I was thinking of.
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I'll have to look at how much is on the clock, but I think my dad's is in the 70k mile range; it's an 04, I believe. Mind you, there was a whole huge clusterfuck with the electric power steering having the connectors corroded away... still original engine, though the upgraded starter is glorious and is going in every rotary I build from here on out. Finding someone doing a V8 swap on one would make me happy though; even if I'm using an older 13B I have at least one project I'd like the 6-speed for. (yes, I'm bored at work)
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Feb 11, 2016 22:16
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I'm pretty sure the spindles are cast or forged steel, not iron - at least all the other Mazda ones I've seen are, though admittedly I haven't messed with FDs.
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Feb 12, 2016 20:11
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kimbo305 posted:On a scale of 1-10, what shape would you rate these as? I'd be uncomfortable if I saw pitting and chips like that on pistons going back into a motor. Is the shape of the rotor surface significantly less important compared to the face and skirts of a piston? I'm not the spyder, but I'll chip in. The pitting on the faces that you're seeing is, to me anyway, about a 4 on one rotor and a 6 on the other - if they were 83-85 12A rotors I'd suck it up and use them because the rotors are NLA, but 13B rotors I'd replace unless I was on a severe budget. The combustion face isn't ridiculously critical and on a lot of rotors the recess is just rough cast iron anyway, but I'd still prefer not to. Anything severe on the sides will almost always drop it down to a 1; the sides are sliding surfaces and actually important. Similarly, the apex and side seal grooves being screwed up will drop them down to at best a 3 - the apex seal grooves can be machined and 3mm apex seals fitted for some applications, and if you're really lucky you can clean side seal grooves, but that's getting to some serious turd polishing. *quickedit* When I was doing engines on my dad's EProd car, I actually had a triage system for boneyard 12A cores. Unfortunately I didn't keep very good records, and he tried building a couple engines out of what he thought were good parts but didn't actually go together. So much for that pile of spares. I'm keeping better records when I get back into serious engine programs. mekilljoydammit fucked around with this message at 14:51 on Feb 15, 2016 |
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Feb 15, 2016 14:44
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ratbert90 posted:Is it not possible to weld + grind rotors? Or is it just not financially worth it? They're cast iron, and the curvature on the flanks is, IIRC, a bit more complicated than it looks - so you'd have to have someone really good at welding cast iron, and come up with a specialized grinder. Theoretically possible, but right now, it's really not worth it. Of course, if anyone wants to start doing castings (ideally, weight optimized ones) that don't originate from Mazda, that'd be cool.
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Feb 16, 2016 19:20
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ratbert90 posted:Fair enough. I was talking about reconditioning them not because they were mismatched, but because of the pitting/wear on them, as from what I remember 12A stuff is getting pretty rare. Or is that not the rotors and just the housings? Housings are easy - a lot of the 13B housings fail by having the chrome flake off towards the edge. Well, since 12A housings are narrower than 13B housings by 10mm, just machine 5mm off each side of the 13B housings and machine o-ring grooves (and machine off where it says "13B") Voila. Rotors are the issue, yeah. I still have a small pile of usable ones, but there's no source for new ones - I think even a lot of big shops are out. More or less all the top level roadrace guys moved away from 12As due to parts availability. I just need to get to doing cast iron instead of just aluminum and problem solved.
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Feb 16, 2016 22:48
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Yikes... at this point I'd just say to hell with it and put a remote filter on - little block in that position to connect the two ports, ideally with gauge ports and an AN fitting to accept oil from the remote filter, boom, done, no PITA oil filter access.
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Feb 20, 2016 16:12
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And people ask me why I stick to my FBs and stuff even though FD prices keep coming down. 
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Feb 24, 2016 21:17
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This is going to sound weird, but how are the boosted ones to drive? It's just always seemed like a boosted 13B in the 350-400hp range can't be ported much, so the redline is ... what, 6500rpm, 7000rpm? It's literally been over a decade since I've driven a rotary with something less aggressive than an EProd spec streetport and a Weber. I just have a feeling that what I have in mind for a "typical rotary powerband" is probably different than people used to the turboed ones.
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Feb 25, 2016 22:56
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Hm, yeah... at the level of street porting I've been doing (at least on Webers, EFI might be better) it's not smooth anymore - everything becomes so optimized that it makes less low end or midrange than a bridge or peripheral port. Been thinking about relatively low boost turbo setups for a ported 13B - at some point I want to do Ye Ultimate FB, but that's down the road. I keep seeing those Lagun mills lately - had one at my last job but had never heard of them before. Aside from the basic "worn out mill vs not worn out mill" deal, are they any good?
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Feb 27, 2016 14:00
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Rotary swap the truck? Someone had to say it. 
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Apr 6, 2016 01:01
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What I'd give for more S5 NA internals. I did order a set of Renesis rotors off ebay though; going to start building up all the ported housings I have kicking around.
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Apr 6, 2016 03:10
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DefaultPeanut posted:20B swap the truck, so you can use some OEM B2000 badging. 4 rotor into B2600, if we're going that direction.
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Apr 6, 2016 12:12
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Nodoze posted:Rotary swap that MIata Hey, that's my thing! (once I get a Miata shell...)
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Apr 7, 2016 20:30
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I just need to find a pre-96 Miata for a price I can afford... I have a suitable engine kicking around, though I may rebuild it with slightly less port... </thread hijack>
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Apr 8, 2016 13:37
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the spyder posted:There's a 89 in my friends dad's garage. It needs a new bumper and fender due to a curb incident, but is otherwise complete. I've been contemplating picking it up for cheap and putting this S5 engine in it, fuel injection and all.... But I have too many projects ATM. It'd be perfect if you weren't on the west coast. I have that peripheral ported 13B kicking around that seems like it'd be way too fun. Ah well, just have to scrape some cash together this summer.
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Apr 8, 2016 18:29
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Rotary Miata urge increasing... (just kidding, there's no room for it to increase) Actually have parts incoming from KMR. Go go gadget race-clearanced RX-8 rotors.
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Apr 20, 2016 18:40
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Cut up rotors are great tools at times actually; I have a corner I clamp in the mill and run a grinding stone in the corner seal pocket for clearancing side seals, and another one where I drilled into the side seal slot, put a scribe in and ran around on a junk side housing to see where the limits are.
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May 3, 2016 02:14
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That's a pretty good score - I've mostly had the other sort of surprise. Too bad the death kart is going away though, that would have been fun too. As a weird question, what would you want for a pitted garbage FD rear iron and rotor?
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May 11, 2016 00:21
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Looks like Beetle swing arms.
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May 11, 2016 18:42
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That... uh. Welp. The exhaust ports are maybe not terrible for a pretty all out engine, albeit there needs to be a lot more chamfer on the closing edge and that method of getting the sleeves out is a bit... special. Might be dead because of the lack of chamfer, hard to tell from here, but overall they're useable for something pretty radical with some cleanup if the chrome's not screwed. That first intake port is a garbage iron now because he skipped the die grinder. The last one might be usable with some cleanup; again kinda on the radical side for a streetport but maybe fixable. This is a pretty decent illustration on why I've learned to do basically everything on these things myself - there's maybe half a dozen builders I'd trust to not give me a pile of poo poo, and precisely zero are local.
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May 18, 2016 23:02
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I figured those were gouges and yeah, trash, the lack of closing chamfer killed it. On the other hand, while I sure wouldn't run exhaust ports like that through any factory manifold, I have parts from a bunch of pro built roadrace engines without the sleeves, and the Mazda Factory Race pport housings didn't have sleeves either. And from experience, holy crap is it hard to get those spring pins out to pull the sleeves. (never tried it on a turbo engine, mind)
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May 19, 2016 01:11
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Dremel on side irons takes for-loving-ever. Of course, air die grinder on side irons still takes a godawful last time. And ideally you want to at least smooth the suckers up a bit with a grinding stone so they don't look like dogshit. All of the irritation of cutting irons is totally not related to why I'm looking into small CNC mills, nope. If we're getting into chat about ports and crap, I'll take some pictures of stuff I have sitting around tonight. I really don't hate the idea behind those exhaust ports as much as everyone else seems to. The execution though... well, you know.
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May 19, 2016 14:03
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The 4-pot calipers with letters are aluminum.
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Jun 2, 2016 14:33
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Not dealt with Defined Autoworks personally, but from what I've seen of their work I wouldn't hesitate to use them.
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Jun 8, 2016 13:42
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| # ¿ May 10, 2024 04:34 |
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My long path to learning to put together a good engine was largely driven by not knowing who I could trust, though it gets harder when "competitive power for this roadrace class" goes in there too. Actually, to this day I only know of a couple builders I'd trust to for sure make competitive power in an EProd engine, and I don't know how many of them would be willing to do customer work other than Mazdatrix. Well, all that and I'm stubborn.
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Jun 8, 2016 14:33
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