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Intake and Nikki Modding
Well the recent thread on hoggin a Nikki, and my own research that I've done for the past who knows how long has finally pushed me over the edge to take these mods for a spin.
First things first, I'm using one of my spare intakes and carbs here so I'm not compromising my main set up in case I ever wish to go back. Now for the work: I've already started on the intake which is an FB model. So far I have removed the shutter valve, anti-afterburn #2 fitting, and soon the auto trans fitting. I've also cut and smoothed the channels which seem to be a fairly common mod after the butterfly is removed. From what I've found, I will not be 'polishing' the runners and instead I just cleaned up some of the worst spots left from the casting process. The outside is still being cleaned, but once all is done with that, I'll start plugging the holes that are no longer needed. I also figured I'd round out the secondary runner for the rear rotor, as due to the situation with the shutter valve, the cast has a near 90 degree angle right below the mounting face that surely can't be doing anything beneficial now that I have the channels. Here's a couple picture of progress so far: https://cimg3.ibsrv.net/gimg/www.rx7...a15a525eb9.jpg https://cimg5.ibsrv.net/gimg/www.rx7...304afabbb4.jpg https://cimg1.ibsrv.net/gimg/www.rx7...5011ca884b.jpg There's the '90' I was talking about. And when I said round out, I really meant fill. As for the carb, I'm planning on doing mech secondaries, the supporting AP mods, trimmed boosters, slimmed throttle shafts, tapped airbleeds, and of course custom Venturi's (probably some other things that have slipped my mind at the moment too). I've got a friend that's setting up a new CNC lathe in the next couple months that I'll be using to make Venturi's from scratch. My hopes is that in using CAD, I'll be able to repeatedly make identical or slightly modified iterations. While I don't have a flow bench, maybe someday if I get access to one I could tackle the ultimate Venturi and throw the file up for the masses. Just a thought... ;) If anyone has any gripes or helpful information, throw them on up here. I'd love to hear some input. I'll be updating this as I make progress. |
The intake is completed (minus reinstalling the brake booster fitting). I ended up plugging all the holes that I didn't need except for the runner end of the auto trans hole. I did the outside end first by mistake and I didn't feel like I could get the other end compressed enough to hold firmly. It would have been a marginal change at best, so better safe that sorry - I know I wouldn't want a chunk of resin flying into my engine.... All the other holes were either shallow enough that I could get the epoxy to fill all the way and stick to the sides, or they had another open end that I could push a rod through to help compress it. For all of the holes I could get to, I cut small notches into one or two walls, so if the plugs come loose from the metal, they'll have a little bump to prevent them from falling out. Had they been perfectly cylindrical like most of the holes were, they could have just slid out if they somehow worked loose. I used JB Weld Steelstik for everything, and while I was impressed with it, the stuff hardens so quickly that you've got to work fast. The only thing I'm worried about is their adherence, which is exactly why I cut the ''bumps'.
Enough explaining, here's some pictures. https://cimg0.ibsrv.net/gimg/www.rx7...bf049c0119.jpg https://cimg4.ibsrv.net/gimg/www.rx7...89540aba27.jpg https://cimg0.ibsrv.net/gimg/www.rx7...bdef211bd7.jpg https://cimg1.ibsrv.net/gimg/www.rx7...14912b05db.jpg And then a couple of cleaned up photos too... https://cimg6.ibsrv.net/gimg/www.rx7...3c1027aa00.jpg https://cimg8.ibsrv.net/gimg/www.rx7...a9c6682fff.jpg I'll probably get this installed either later this week or the following weekend. Next up is the Nikki work. I've got a couple options: I have a complete SA carb that is extremely dirty and rusty (no clue where it came from), and then a 83+ carb that is clean but missing a T-body because I installed it on my '82 carb so I could have vac advance. That said, I still have the '82 T-body but it doesn't have vac advance. What ever carb I build it will be a permanent assembly in the sense that all the parts will belong to that one carb and will not be switched around again. This is still a DD, so vac advance would be nice for mileage and around town. How much of a hit do you think part throttle power and mpg would take if I skipped the vac advance? I do realize that being modified, mileage will take a hit regardless. Thoughts? |
JB Weld will work fine, don't sweat it too much.
Don't mix carb and throttle bodies, use the same from the same year, there are small differences that can get you at tuning time because some hole or another doesn't line up. |
Not true. Only SA and FB differ in any significant way. But regarding the differences between 81-82 and 83, vs 84-85, those are the three groups in the FB production run and the main difference here is the richer solenoid circuit that the 84-85 had which earlier models didn't have (unless you go back to SA, which had it). It was a pressed in jet in the 84-85 baseplates. There was a corresponding hole and a solenoid between the secondaries unrelated to them as it connected in a Y arrangement down at the primary barrels in the baseplate. Also there were some air bleeds at the top of the main body which controlled, well, the air. The solenoid was activated at idle to allow a richer mixture to maybe warm the cats up quicker for emissions purposes. Regarding 81-82 to 83, there was only one major difference allowing you to tell them apart. 81-82 had a 12mm nut on the OMP lifting lever side of the primary shaft while the 83 and later had a 10mm nut there. I don't think there are any holes that differ between these groups.
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Interesting... When I did the T-body switch I checked all the holes for alignment and both were identical other than the omission of the vac advance hole in the 82. There was probably that pressed in jet too, although I'm not positive. I do remember the throttle shafts being slightly different in terms of the way linkages mounted and also that there was a different sized nut on one. I want to say that one also had a smaller shaft than the other, but I might be crazy. I'll take a look at them next chance I get.
The 83+ carb that I have does contain an extra jet and also a plug below the triangular protrusion (opposite the fuel lines) of the airhorn, is that what you are referring to as part of the richer solenoid circuit? I remember the one on the SA carb I ran, but this carb doesn't have the solenoid. Oh wait a second, I just remembered I had a friend tear down this carb and he may have removed it, although I honestly don't remember. This carb also has the newer style vent solenoid - the one where there is only one visible wire and it is either threaded or pressed in as opposed to using the triangularly arranged screws and bracket. And to update my non-posted post.... The carb does have the spot for the richer solenoid. Here's a picture https://cimg2.ibsrv.net/gimg/www.rx7...13306eebc2.jpg And here's a photo of the vent solenoid I was referring to https://cimg2.ibsrv.net/gimg/www.rx7...d2adbb03f6.jpg I still have the richer solenoid although since I'm not running emissions parts anymore, could I just plug the circuit? This is where I wish that I was modifying my 82, just because it was simpler from the start :). Anyway, I'm not gonna mod the 82 since it runs reliably as is. So from what you've said, it sounds like this is an 84-85 carb. The question remains though, swap T-bodies again to keep vac advance, or do without it. I guess another angle to look at is that the modded Nikki will already be harsher on mpg, so perhaps I should keep the current one as is so that I can always go back to my good mpg build if I desire, rather than averaging the two together and making neither outstanding. Does the vac advance really make much of a difference down low/part throttle? I know I didn't notice much of a difference when I added it a while back so.... Who runs it and who doesn't, and what logic do ya have to support the decision? Thanks thus far. |
Ah yes, I don't think in terms of vac advance but indeed there could be one additional hole for it. Maybe, I'd have to look. There are two nipples on the baseplate that have a timed vacuum function but I have not explored them yet.
Adding to what I mentioned earlier, the 81-82 shaft is slightly shorter on the throttle lever side but a couple mm, compared to 83-85. The 83-85 shafts, being slightly longer, are easier to work with when doing custom linkage setups for project cars. 83 was the first year for the single wire smaller body vent solenoid. It is threaded into a larger pressed-in brass housing. To gut these, I grind out the nylon valve with a narrow dremel bit, then break it off with short needle nose plier, then remove the small spring from the solenoid and cut the wire (so you won't have to keep the trigger wire in your rats nest wire bundle if you choose to de-loom, but it can be handy to keep). Then thread the solenoid in with the same crush washer or a new one from a rebuild kit. If 82 and older with the larger body and three screws, this can be fully removed and a flat aluminum plate added with the triangular gasket from a rebuild kit. Or make your own. you have to make the aluminum cover plate anyway... Yes you can plug the circuit. I like to use a piece of aluminum rod and drill the hole slightly smaller than the diameter of the rod. This is the hole at the underside of the main body sort of in between the secondary venturis. Then I use red loctite and hammer the rod in there using a center punch tool. The richer solenoid can be kept with the spring loaded rod, or remove the hole thing and fill with quicksteel. I've done it both ways. I do keep the air bleeds above just because there is direct communication with the float bowl to the left (rear side of carb when installed). You will see the machined holes in the float bowl and corresponding circuit pathways outside of the main body. Oh and I do clip the wires on the solenoid if keeping it, to discourage anyone from thinking they still need to be connected on the 84-85 cars. |
So the deal with the timed vacuum nipples is that the second to front one on the '82 deadheads on the transition from the baseplate to the T-body. Normally there would be a hole that would continue from the baseplate to a slot just above the front primary butterfly. This hole and slot are missing on the '82 for whatever reason, and as such the second to front nipple goes literally nowhere - it had confused me for the longest time until I took it all part to see if something was seriously clogged. Normally there are two timed slots in the front primary, one that is about level to the closed butterfly, and one just above it set off to the side a bit. Now that's just from memory, so I may have mentioned something off by a little.
As for the longer shaft, it sounds like the benefit is negligible being only a couple mm. Does the extra length really come in use when making custom linkages? As in, is it worth swapping back just for that (omitting the vac advance part of the equation)? I'm also trying to keep the car on the road while I'm doing this work, so swapping would mean more time down time (I swapped linkage parts around so that I could use the SA TPS, although that's getting removed now that smog equipment is gone). You know what, I just remembered that in switching parts for the TPS, I swapped over one shaft and not the other because there was some sort of matching issue. I think I swapped the primary shaft and kept the secondary in the original T-body because the SA TPS sensor linkage wouldn't mount to the later shaft. So in theory, on my bench I have the '82 T-body and its secondary shaft, and then the 84-85 primary shaft. Got to love it when parts get all mixed around... Are both later shafts longer, or would this arrangement work just fine? I think I'll keep the vent solenoid for now since for the time being I'm still running the PCV and related components. I'm also doing away with the altitude compensator. I'm assuming that I can just install a block off plate and not worry about the jet and two other holes? Any reason to, or to not block them off? I figured I'd also remove the two fittings up top for its vacuum lines and then just plug the other ends where ever they go - the carb is fully dissembled minus the jets so I don't know where that would be at the moment. And for plugging the hole with the aluminum rod, I'm assuming you meant the hole that goes from between the secondary venturi's (as you said) and then is angled up towards the center of the carb where it then meets with the richer solenoid valve? And yes, I just checked the float bowl and I see the two holes and circuit pathways you are referring to for the jet. Speaking of jets, I just removed the brass plug that's next to the richer solenoid jet, and I noticed what looks like a weight. I took it out and there's no check ball below it. Was there supposed to be one? Oh so many questions... |
Normally the second nipple on the carb spacer has zero vacuum at idle and shows vacuum when the throttle is actuated.
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Don't swap it. I was mentioning it anecdotally only. The extra length makes installing the 12mm nut a little bit easier if you've just done anything with the linkage. But the 81-82 shafts are still fine to deal with because, and you have to really ask yourself, how often does anyone ever do any linkage work? Next to never.
I cut out a 1/4 aluminum plate for the alt comp removal and make a gasket for it or use the OEM one in a 12A gasket set from Mazdatrix (yes the OEM Mazda gasket set for N201 has a beige colored carb gasket among other gaskets in there for whatever reason). Then I take out the 40 stamped air bleed under the air horn and fill it with solder from the back side (in case the solder detaches from the brass, it can't fall into the engine). There is virtually nothing to be done about the two vertical holes next to the booster that communicate with the alt comp. Some people have hammered check balls into them but I don't like that idea as it creates a space that water will get into and can't come out of if you ever have to wash the carb in the future. I've tried using full length phenolic inserts from SA carbs (instead of the castellated nylon ones found stock in 81-85 carbs), but sometimes they don't fully block off the internal diagonal holes. But I can tell you if you manage to block off even one of them, through a series of means at your disposal, the carb will have a more stable transition circuit if you are going with larger venturis than stock. The altitude compensator circuit is intimately linked with the primary circuit through the primary booster / air bleed / emulsion tube by way of the small diagonal holes and the vertical holes that connect with the air horn. And this is also linked to the primary transition circuit and the primary idle circuit. It is all one big mess and can cause issues. No check ball below that brass weight. Indeed there are a lot of questions and secrets about these carbs that even I am still learning. |
So it sounds like I'm staying with the T-body I've got now - '82 casting, no vac advance, '82 secondary shaft assembly, and an 84-85 primary assembly.
As for the block off plate, I'll probably just make a gasket with some of the roll paper I've got lying around, and cut out a new plate when I do the ones for the intake. It would seem like I could just fill those holes by the booster with JB weld again like I did in the intake with no ill effects..? And I had actually been referring to the two brass hose fittings on top of the airhorn/altitude comp. I know the '82 doesn't have these fittings, and perhaps the '83 doesn't either. They might just be an 84-85 thing, I honestly don't know. Regardless, if I understand correctly, I should plug everything related to the altitude comp that I can, yeah? And thanks for confirming the lack of a check ball. For now most of these questions I'm asking are conceptual as I haven't had time yet to start diving into the carb. As no carb that I have worked on to this point has had these 'features', I'm really just working with the short time I spent while taking those photos. I'm sure this will all make better sense once I start messing around with the carb. |
The holes by the booster? I don't understand.
Brass hose fittings? No those are steel. One has a tiny air bleed pressed in made of brass. They are an 84-85 thing only. Yes, block them all off. |
Originally Posted by Jeff20B
(Post 12325685)
There is virtually nothing to be done about the two vertical holes next to the booster that communicate with the alt comp.
https://cimg2.ibsrv.net/gimg/www.rx7...3a99003c7e.jpg Which holes had you meant? And yes, the steel hose fittings; seems I just had brass parts on my mind... |
Jeff your everywhere with your mad scientist info ! Great
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Just a quick progress update.
I made the split air block off plate today and sometime here I'll make the ACV one - I'm planning on installing the intake Sunday or Monday. Also got the boosters started and I removed all of them without any damages - I used the taped pliers method as I don't have enough spare airbleeds to destine one as a tool. I only had a little time this afternoon, but I started cleaning up one of the secondary boosters. The centering tab removal was a success, and I started to make the airfoil shape on the support arm. Unfortunately the Dremel sandpaper wheel I was using to remove the casting line was more aggressive than expected so this isn't the prettiest one. Although this is my first one ever (and it's not nearly done yet), so I'd say I'm headed in the right direction. I've only done a quick polish on the side facing the camera and I'm planning on going back and smoothing things out a little more with some higher grit paper before I'm done. Here's a picture of it so far. https://cimg4.ibsrv.net/gimg/www.rx7...9d3441181e.jpg I don't think you can see it in that photo, but the worst carnage from the grit wheel are some minor low spots that won't level out. They're almost unnoticeable, but they're there nonetheless. I've been doing the sanding by hand since that incident. I'm also not sure what to do about the inside, other than just clean it up - not really seeing a way or a reason to get a polishing bit in there. Doubt I'll get to work on anything again until Sunday, so expect an update sometime around then. |
Well I'm in the process of swapping intakes. I haven't removed the old one yet as I still have to drain the coolant, although when looking at it after removing my ACV block off plate that I'm reusing, I noticed the exhaust check valve. It's missing in my other intake and I'm debating whether there's any point in trying to move it over. Seeing that with the block off plate that exhaust isn't going anywhere anyways, is there any logic in having it as a second means to stop the exhaust gasses from potentially making it past the block off plate? Personally I would say no, but I figured I'd throw it out here for opinions.
Here's a picture of what I'm referring to: https://cimg7.ibsrv.net/gimg/www.rx7...caa444006f.jpg |
Well yesterday I didn't end up switching over that check valve, although I still could if there's a reason to.
Anyway......... The intake is installed and dang is the car smooth. Here's just a quick rundown of everything I did on the intake: removed shutter valve, cut rear rotor runner's channel to match front (essentially making it SA style), ported both channels, filled original rear runner 'mix hole', filled 90 in rear secondary to smooth and match runner profile, filled all vacuum holes other than the brake booster, removed casting imperfections, ACV delete, and #2 anti-afterburn valve delete. A few weeks ago I tried disconnecting the vacuum signal to the #2 anti-afterburn valve and I found the car backfired much less. The line from it to the rats nest had been plugged for some time, but as I didn't know for certain how it worked, I reconnected it the other line that goes to the T-body. Yesterday I fully deleted it thanks to the hole on the intake being plugged, and wow did it smooth things out. You used to be able to hear it if you would rev or run up in the rpm's and then let off quick (it was a sort of 'cht cht cht cht...' sound), and now that's gone. I also used to get a lot more pops and burbles when shifting and now it's practically silent so that's cool I suppose. The overall intake mods seem to have not only improved power (according to the seat Dyno), but most definitely responsiveness and smoothing of the powerband. First gear doesn't last long enough for darned near anything now (pretend this text is a wink because I ran out of photo space). The car also sounds much different, particularly on start-up. Speaking of the exhaust, I replaced my muffler gasket yesterday so that probably contributed some to the sound too. Here's a picture of how bad the leak was (and yes this old gasket was reused from my parts car because I didn't anticipate having to order it from RB or Mazdatrix at the time): https://cimg7.ibsrv.net/gimg/www.rx7...a7993865aa.jpg https://cimg7.ibsrv.net/gimg/www.rx7...c2e29d0e65.jpg Ironically, this gasket is the OEM size and yet unbeknownst to me until yesterday, I have the larger 'RB' sized pipes and flanges. The sealing rings on this old gasket weren't even touching metal - no wonder it's in such rough shape. The internal material is also completely missing and it turned my new bolts black in that area. https://cimg5.ibsrv.net/gimg/www.rx7...de9ac8697a.jpg Here's a quick size comparison between the two gaskets: https://cimg8.ibsrv.net/gimg/www.rx7...1fe7b970f5.jpg So now I'm really curious as to what muffler I have. It's dual pipes in and out, bare metal, and really low profile. The pipes running to the tips are painted black and then the tips are chrome, angled back from top to bottom, and have perforations on the inside sorta like a glass pack. No markings or identification that I could find. I doubt anyone would recognize it, but you know, there's a chance. Removing the old intake was also rather odd because my ACV block off plate and gasket were covered with what looked like oil. Not on the outside, just the inside, and this 'oil' was actually sitting in the split air part of the ACV intake holes - not the exhaust. No clue where it came from, although I feel like it might be condensed water that was never allowed to escape. Strange nonetheless. Here's a picture of the oily stuff: https://cimg2.ibsrv.net/gimg/www.rx7...efde935b83.jpg And finally a picture of the installed intake: https://cimg3.ibsrv.net/gimg/www.rx7...3b7c74cf7c.jpg Today I'm changing belts, figuring out what is clicking under my dash at idle that I can remove or fix, and working more on the performance carb. |
Well I'd say it's about time for another update.
The car is still running great, and so far I'm quite pleased with the intake work; no drawbacks to be found. I've started some more work on the carb, nothing major (I have yet to start on the linkages), but the boosters are coming along and I've been cleaning up the main body and air horn. Here's a couple pictures of a finalized secondary booster. It's not perfect, but I'd call it good enough. https://cimg4.ibsrv.net/gimg/www.rx7...51df6166ef.jpg https://cimg2.ibsrv.net/gimg/www.rx7...045ed3c009.jpg https://cimg3.ibsrv.net/gimg/www.rx7...b51dc9aa8f.jpg Most of the work I've done on the carb so far is just cleaning. I did find the right bolt for the primary booster (to remove it that is) and it's an M7 x 1.0 thread. I think the secondary is M9 x 1.0, although I have yet to come across a bolt of that size. The carb is fully disassembled and the rebuild kit just came in a couple days ago. So now for a couple questions:
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1. Don't follow any advice about drilling the nozzle and the banjo bolt until you have test driven your carb with all the mods. Then try drilling them a tiny bit larger than stock to start. What ever you do, never drill them as large as recommended by others. The stock size is tiny, like .4mm or .5mm. I've seen a racing one with a 6 stamped on the bolt head indicating .6mm. I usually go for a .90mm to a 1.20mm but never any larger and it depends on what the carb will be used for.
2. The biggest problems with stock carbs regarding stability is all the excessive amounts of air they let in through air bleeds and controlled vacuum leaks. It's all so the choke system will function as intended. Because I remove the choke flap due to how restrictive it is, I've been able to also reduce the excess air and end up with a vastly better carb. So to answer your question, it is an ongoing process of trying things and observing the results. 3. There are various ways of dealing with PCV. The OEM system only had a purge valve that was tied into a lot of other systems. It can be replaced by an aftermarket PCV valve and hooked to the middle nipple on the phenolic spacer as this one flows pretty much equally to both primary runners in the manifold. Study the spacer and you will see that it has a Y shaped channel. But you may also need to add a tiny restrictor somewhere in the line, depending on the results. |
First off, thanks for the good info as always.
Second, I've been contemplating removing the choke system (keeping the fast idle though). Being up here in Oregon, where just a few weeks ago we were seeing temps in the 20's, I'm a bit worried about cold starts. I was thinking I could just try without it for a couple days - or one test if I can't get it to start - and then reinstall it if it doesn't work out. The issue I'm seeing right now is temporarily, and potentially permanently plugging the holes for the choke flap rod. If I try without the choke and it doesn't work, I'd like to be able to reinstall it, but just leaving them open is surely no good for debris getting into the carb. In all the threads I've read so far no one mentions plugging the holes. I'm assuming that either this is just assumed to be done by what ever method someone wishes or that they're left open. Thoughts on this? Also I've been doing some more poking around the altitude compensator system and it seems like I can plug all the holes no problem like you had said a couple posts back. And don't take that as a challenge on your info, I just like to fully understand things before I start throwing the JB weld around. I'm still doing research and investigating (not to mention cleaning) but I'm getting progressively closer to the mod and reassembly stage. I've got a few more questions floating around in my head, but I think I may have confused something up there and so I'll post with those when I'm looking at the carb again. |
So I think I figured out what holes you were talking about Jeff. I probably just severely misread your post 'cause I don't know how I missed these. In the photos below I'm referring to the two vertical holes that run in the divider between the primaries and secondaries (next to the boosters like you said originally).
https://cimg0.ibsrv.net/gimg/www.rx7...feb85d02e8.jpg https://cimg6.ibsrv.net/gimg/www.rx7...68ec15b973.jpg So from what you said, and my own investigating with the air compressor, these holes go to the primary main airbleed / fuel jet cavity. What makes them so difficult to block off? I can see where the diagonal holes were drilled to connect these 'tubes' with the airbleed area, but wouldn't just blocking off the tubes themselves solve the issue? Or do the diagonal holes need to be blocked off too? Is that why you use the SA "phenolic inserts"? I know I'm repeating a bunch of what you already said, but I'm just making sure I've got this right. I have an SA carb that I'm using as a parts carb so I could swap those in no problem. Also by phenolic inserts I'm assuming you mean these things, and that by full length you meant the SA ones don't have those feet: https://cimg4.ibsrv.net/gimg/www.rx7...a719df4e1c.jpg Also, if water is a worry, wouldn't it just work to plug both ends of the passages on the air horn? That way water could never enter a sealed part of the circuit, and the SA inserts would just be an extra precaution (also no water could get stuck in the body since there would be no permanent seals in it). Right now that last combo I mentioned seems like the best option, although if there's some reason it wouldn't work out, let me know. The previous post's questions still stand. |
I believe that last post of mine warrants some rephrasing...
So if the vertical holes in the body were plugged, that would leave the connecting diagonal holes as a possible way for water to enter and get stuck in that part of the circuit during a wash. That's why you suggest not capping the vertical holes in the body, and rather advise running the SA phenolic inserts as they are a removable way to block off the diagonal holes. Being removable, there is no worry for potential water getting stuck in the passages. Although, you also mentioned that the SA phenolic inserts don't always seal completely and so... As for my addition to that, both ends of the circuit on the airhorn side of things are easy to get to. If I blocked the vertical holes on the air horn, and then blocked the hole where they meet at the altitude compensator, that would provide a completely sealed circuit that no water could get into. If I did both the SA phenolic inserts and the aforementioned, surely that would be an effective way of fully blocking off the circuit without a worry of invasive water. Any unforeseen issues with that method? That's what the last post was aiming to convey; hopefully that made a little more sense. |
Boosters are done!
I had taken a little break from them to do the carb cleaning (which now done too). Just finished the primaries last night. Here's a few pictures. https://cimg7.ibsrv.net/gimg/www.rx7...30b994344b.jpg https://cimg9.ibsrv.net/gimg/www.rx7...3a9a310078.jpg https://cimg4.ibsrv.net/gimg/www.rx7...0ef00eb4dc.jpg https://cimg5.ibsrv.net/gimg/www.rx7...e004ea2240.jpg https://cimg1.ibsrv.net/gimg/www.rx7...76eadc282b.jpg I will say that the primaries were a little different to do as they have a 'two level' support arm. Due to that, there are a couple triangular spots on each side that show the remains of those supports. I didn't want to remove much more material from that area, and it should be better than stock regardless. For anyone who may copy those in the future, I suggest not cutting the angle into the left over centering arm on the primaries. It take a long time to round them out using mini files, and I seriously doubt there's much of a gain, if any. As I alluded to up top, the carb body and air horn are done being cleaned and are now being checked for any blocked passages. I've made the altitude compensator block off plate and gasket, and the next step is getting a few peices out of my parts carb. Still curious about the content in my past few posts. |
The carb is getting much closer. Boosters are installing and centered, fuel jets and airbleeds are in, and really the only peices left before the carb can go back together are the AP mods, filling those passages (which Jeff if you could confirm that I'm not crazy, that would be appreciated), and figuring out what needle/seat/float/clip combo I want to use. As of now I've had the best luck with SA floats and the like, but I would doubt that the FB floats and such have any real issues (perhaps just the sets I have do...). Anyway, with my other carb I was always having flooding issues with the FB floats and I've got an extra set of matching SA floats, needles, etc. that I'll probably end up using - I'll see as the install gets closer.
I should mention that while I'm nearly done with the carb, the t-body hasn't been touched yet. I've still got to work out the linkages, thin the throttle shafts, and just some overall prep. Here's a couple pictures of stuff as of now. The body: https://cimg2.ibsrv.net/gimg/www.rx7...a999ca4860.jpg And the SA phenolic inserts just for documentation: https://cimg4.ibsrv.net/gimg/www.rx7...519252fd57.jpg Considering there aren't too many signal affecting mods yet (no Venturi hogging), I put in the SA primary jet (93 I believe) as it's a point up from the stock 84/85 primary. I left the secondaries stock as there were no year differences, and I went down a size on the primary no. 2 airbleeds (I think; I did this a couple days ago so I'm not positive which bleed it was or what the size is without going back and looking at it) by using the SA bleeds. This is really just a starting point right now as I still need to learn more about how the airbleeds affect different load and rpm scenarios. I doubt I'll get much more work done until the end of the week, so stay tuned for more updates most likely starting Friday night or Saturday. |
Good effort in documenting your work. As for filling passages you mentioned... What passages?
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By passages I meant the vertical holes that are connected to the altitude compensator. The full explanation of what I meant is in post's #20 and 21. Post #20 explains it a little better, but both have some valuable content regarding the phenolic inserts and capping the vertical holes.
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