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Couple varieties of endgame depending on complexity. This all got kicked off by a conversation with someone about spreading the valve centerline to put bigger seats and valves in... and none of us were sure if there was room to do that without hitting water. So now, if everything works right I have a complete 3d model of where metal is, so I know where the OEM castings can be ported or reworked. Next step up the complexity range, I do have a flowbench. So one thing that I can do is 3d print just port sections out of plastic (think the combustion chamber and ports for one cylinder, without water jacket or anything) and rework stuff by hand, which I can feed back to the 3d model. And working with others with the right tools, could much more easily turn that into CNC toolpaths. At the very least, it's much cheaper to try port experiments on a $1 of 3d printed plastic than it is on used heads with value. It's also an impetus to get to leaning simulation stuff, since there's a variety of relevant CFD suites that I haven't bothered with due to lack of a project. I suspect there's a lot that can be done moving air space for ports around within the constraints of all of the port openings too, so new manifolds aren't necessarily a given, but even if they are I know a few people who are doing time attack builds who might be willing to try stuff, especially if I prove it out on the engine dyno. ... which I need to get to. The big reason is that I had a brainstorm about it one day, there's a lot of potential uses I can see for the idea, and I wanted to try it with parts I had hanging around, especially since work has a big loving shell mill I can use to take skim cuts.
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Jun 2, 2018 13:40
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Funny thing, I was just doing some reading... http://www.training.prace-ri.eu/uploads/tx_pracetmo/development_of_Advanced_Combustion_Model.pdf This might point you in the right direction with regards to your solvers and meshing. Very fun.
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Jun 2, 2018 18:29
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Has anybody been crazy enough to try making their own Wankel irons and housings? I'd imagine that casting irons wouldn't be too far removed from what you're doing, but you'd have to figure out how to chrome the combustion chambers as perfectly as possible...Larrymer posted:Neat, but what's your end game here? Do you have any sort of simulation software to show that changes you make will actually be beneficial? Moving ports sound like a huge pain because then you're designing me manifolds too. Otherwise without changes, you'd probably be better off buying used heads than backyard casting them, yeah? Automotive Insanity is the name of the forum.
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Jun 2, 2018 22:17
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MiniFoo posted:Has anybody been crazy enough to try making their own Wankel irons and housings? I'd imagine that casting irons wouldn't be too far removed from what you're doing, but you'd have to figure out how to chrome the combustion chambers as perfectly as possible... I dunno, but it's on the list. That and rotors.
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Jun 2, 2018 22:35
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MiniFoo posted:Has anybody been crazy enough to try making their own Wankel irons and housings? I'd imagine that casting irons wouldn't be too far removed from what you're doing, but you'd have to figure out how to chrome the combustion chambers as perfectly as possible... I think you can pay people to rechrome used housings so presumably you could cast your own and then send them there.
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Jun 5, 2018 22:58
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Oh I dunno, what were you doing today? https://www.youtube.com/watch?v=g-KxZViMckI
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Jun 6, 2018 00:58
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That's awesome, how many slices are you taking?
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Jun 6, 2018 23:58
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... around 130. It's going to be a while before I'm done.
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Jun 7, 2018 01:49
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One inch of head turned into metal chips, four to go (or so)
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Jun 7, 2018 13:59
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mustard_tiger posted:I think you can pay people to rechrome used housings so presumably you could cast your own and then send them there. I keep hearing this, but have never seen anyone that actually did it. Would be a good thing, since new first-gen RX-7 and earlier housings are now pretty much nonexistent.
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Jun 7, 2018 15:28
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I dunno. I was thinking in terms of trying to find a place to nikasil plate them and skip the sheetmetal liner. The nice thing about the early housings is that if you have machine tools, you can just turn the later housings into an earlier one - cut o-ring grooves and or narrow them for a 12A housing. Pain in the rear end though.
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Jun 7, 2018 15:39
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There was someone on RX7Club or somewhere years ago who was trying to build a rig to spray the wear surface with a ceramic-metallic coating. To get something resembling even coating, the spray head would have to follow the epitrochoid shape. His thread sort of just petered out.
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Jun 7, 2018 20:03
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Nikasil and some other similar ones are electroplating processes. I know flame spraying has advantages too, but it's not the only way.
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Jun 7, 2018 20:09
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Oh, I know. That was just what this guy was trying to do. It had merit due to the properties of the ceramic, though no one was sure how well apex seals would actually seal against it.
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Jun 7, 2018 20:59
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Apex seal sealing isn't rocket surgery - it's a sliding seal between cast iron and whatever. They're fundamentally funny shaped piston rings.
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Jun 7, 2018 21:35
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Welp, today was my daughter's due date, so go figure my wife and I are kinda wrecked. Going to go out of town for a few days.
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Jun 9, 2018 15:20
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Man, that sucks. Go decompress and take care of yourselves.
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Jun 9, 2018 15:49
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Hiking was awesome... I'll repost some of my wife's photos somewhere publicly accessible. In the mean time though, back to the WRX... and despite breaking a few loving emissions hoses (yay 190k mile rubber) I got the intake manifold stuff all done! Fuel line recall done, new fuel rails, new (bigger) injectors, TGV deletes with gasket matching, and silicone turbo inlet. Now to finish the frankenstein 5 speed - V6 STI (so the same gear stack as the Legacy GT but with 4.44 FD) with an RA DCCD center (which was a pain in the rear end to get the parts together to make fit but oh well) and an OBX front torsen. Probably going to resist scope creep and not bother with an aftermarket downpipe right now as I have to TIG a cat into it - basically I decided I trust the Chinese downpipe fine, but don't trust a Chinese cat converter so just got a Magnaflow one.
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Jun 14, 2018 23:03
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Except for some gasket scraping and RTV, got my frankentrans together! I even did a little writeup on NASIOCmekilljoydammit posted:OK, pictures will follow once I find the pictures I took. First off though, don't do this. I'm writing this because I could never find answers, and I did it, but I also race RX-7s so I'm odd. But hey, it's not automotive sanity, right?
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Jun 15, 2018 21:48
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At the part where a machine shop can't save the day is where I'd say 2-3k for a 6 speed is totally worth it but it's wicked cool that you stuck it out. Way more interesting than another STI swap and learning stuff rules.
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Jun 16, 2018 21:15
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It's... OK, to be clear, I could have machined myself out of the problem. The seating surfaces of the bearings that support the output transfer gears are farther apart on the Phase 1 stuff and there's not room to just machine the casings though... all the gears are in slightly different places. I think by machining a spacer plate for between the end part of the extension housing and the main part, machining a couple places bearings go and maybe lathing some shafts I could have made it work. Kinda. There's linear ball bearings on the shift rod on the Phase 2 extension housing and I broke into the tunnel they go clearancing it for the DCCD center but I think that would have still been OK. It does hit a point where you say "... this is stupid, I'm just going to hunt down the right parts" though, and this is coming from a man who is reverse engineering a cylinder head. I think if I couldn't have made the DCCD center work with plain ordinary Phase 1 parts I'd have just said gently caress it, sold those parts to some other unsuspecting sucker, and transferred the center from my WRX over. Or the RS in my field.  Case ID sticker. Subaru connoisseurs will know this as a V6 STI non-RA transmission, with the close-but-still-relatively-not-freeway-terrible gear stack later used in the Legacy GT, plus a 4.44 final drive.  One example of special secret squirrel RA parts - that plate is a piece of flat steel on the normal Phase 1 transmissions, but on the RA ones it's cast with that little dingus. Said dingus orients a metal arm to hold the wires for the DCCD out of the way so they don't wrap around the internal gearing or something stupid.  The final frankentrans! I also threw an OBX torsen type LSD in the front while it was open because gently caress it.
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Jun 17, 2018 01:09
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You realize that by including it in the picture, we’re going to need to know more about that lawnmower powered contraption behind the transmission now. Edit: also, after all that, you’ve got the nerve to question me putting an old EFI in an even older car... 
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Jun 17, 2018 02:39
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My dad's barn is not well organized. Thing in the background is the frame and motive parts for a cyclekart - basically simple go-karts styled after pre-war racers. The wood bodywork isn't attached but I think my dad's styling after an Aston. 6.5hp hondaclone, CVT, dead axle front with leaf springs... we're going with better brakes than the "normal" design. Parents and I both have fields so we're going to mow tracks and race. And yes, doing poo poo like this is why I recommend other people don't do poo poo like this; I've spent whole heaps of time wondering if I blew hundreds of bucks on poo poo that I will never be able to make work. Literally until last week I wasn't 100% confident it would all fit together, and if I'd left well enough alone and not opened up the trans (IE no torsen and no DCCD) I could have had it into my WRX at least 3 years ago or something. I know it was kind of a joke, but no, I have something brokebrained in me that makes me want to do things my specific way even if it's headbutting my way through a brick wall.
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Jun 17, 2018 03:29
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I think that's called being an engineer sometimes. I spent 300 dollars on an obsolete axle from a dead car maker from 1974, found a new old stock gearset for it because it's not the right pinion offset to use new ones, plus hundreds on other parts, plus tons of time to put a custom Dana 70 in my truck instead of outboarding my leafs 4 inches and using an axle I already had or spending a bit more on a different one that would bolt in. I swear I have rational reasons for this.
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Jun 19, 2018 23:39
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... yeah that sounds familiar.
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Jun 20, 2018 00:49
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kastein posted:I think that's called being an engineer sometimes. I do my own version of dumb poo poo as well, but usually try not to reinvent the wheel.
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Jun 21, 2018 17:01
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I don't care what thread it ends up in but yeah I'd love a hell of a lot more info on the cyclecart please, they're awesome.
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Jun 23, 2018 09:32
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No new pics because lazy, but engine and trans is now back in the WRX! Not running yet though, but good enough we can roll it out and get to work on the MX-5. In other news, guess who has two thumbs and picked up a 1st gen RX-7 glass sunroof for $60! 
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Jul 5, 2018 23:55
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are you a wizard
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Jul 6, 2018 01:23
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Yup.
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Jul 6, 2018 01:35
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mekilljoydammit posted:No new pics because lazy, but engine and trans is now back in the WRX! Not running yet though, but good enough we can roll it out and get to work on the MX-5. I bought mine for $20 from a wrecking yard... 20 years ago. Then, since it was for an FB, and my car an SA, traded with a guy who somehow got a similar deal on an SA glass moonroof. I also picked up a 3-piece wraparound rear spoiler for $20 from the same car as the glass moonroof at the same time. One of the retainers on the moonroof broke (stupid pot metal), so I need to fabricate one from billet aluminum when I get it back on the road. edit: sold another FB glass moonroof with the GSL-SE I sold a few months ago. Given what I sold the car for (cheap!), I should have kept the moonroof and sold it separately. Had the bag and everything.
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Jul 6, 2018 18:21
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I'm thinking I'm going to do a relatively quick street build on one of the cars I have a title for. The peripheral port 13B I have sitting around, Miata trans, fender flares, repaint, cutting and hacking on suspension, then drive it.
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Jul 6, 2018 19:10
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I wish I’d kept the one-piece factory spoiler for my FB when I sold it. Gonna be a pain in the dick sourcing another one if I ever get an RX7 again (I won’t  )
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Jul 6, 2018 20:49
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Terrible Robot posted:I wish I’d kept the one-piece factory spoiler for my FB when I sold it. Gonna be a pain in the dick sourcing another one if I ever get an RX7 again (I won’t To be fair, I did have to fix a hole in the top surface, and a crack in both corners on my 3-piece. I keep debating making it a one piece, but I actually got it to fit pretty well, and I was amazed that I managed to make the repairs invisible. edit: mekilljoydammit posted:I'm thinking I'm going to do a relatively quick street build on one of the cars I have a title for. The peripheral port 13B I have sitting around, Miata trans, fender flares, repaint, cutting and hacking on suspension, then drive it.
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Jul 6, 2018 21:59
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 Hello there, old friend... let's get you cleaned up.
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Jul 10, 2018 23:39
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Oooooo, peri-port!
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Jul 12, 2018 00:29
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That's a neato engine stand, did you make it?
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Jul 12, 2018 00:33
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Friend did... or someone he bought an engine from at some point? I've made a copy or two over the years though. I'm thinking of moving to a snowmobile throttle body instead of carb, at least partially because we sold that IDA. That and going to a more conventional exhaust setup and doing a new header. Nothing major; sucker still turns over so can't be that bad despite the storage.
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Jul 12, 2018 01:17
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I need to build one of those with wheels. Currently rolling mine around on a furniture dolly. Speaking of which: don't buy the goddamned Harbor Freight ones. The wheels roll fine, but they won't *turn* with a load on them. I have to go get some better casters from Northern Tool now to fix the two HF dollies I have.
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Jul 12, 2018 18:42
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Darchangel posted:Speaking of which: don't buy the goddamned Harbor Freight ones. The wheels roll fine, but they won't *turn* with a load on them. I have to go get some better casters from Northern Tool now to fix the two HF dollies I have.
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Jul 12, 2018 21:07
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