lordcupkake

I'm going to preface this post with the fact that before owning this car I had no experience with carburetors whatsoever and thus this has been a uge learning process for me.

I have a 1983 Rx7 that is somewhat stock, but also definitely has some aftermarket mods done to it. When I bought the car it ran well and utilized a Holley carb with a Racing Beat intake that overall looked nice and ran well. After about of month of owning the car it stopped running well and would smoke up quite a bit on startup (white smoke out tailpipes) and also would idle high and even die if idle speed went below about 1100rpm. I took the car into a shop and was told at least the smoke was not a result of a coolant leak as the coolant systems was found to hold pressure well and has no issues - the issue was the carb.

It was running a Holley with numbers "80457-2" which I believe is the serial number and "2798" stamped into it. I was told this carb is too big for the rx7 anyway and I should consider replacing the carb since it wasn't running right and wasn't actually the right size anyway. That was no issue, as I had a spare Nikki (and stock intake manifold) from when I purchased the car (prev owner said the carb was the wrong size too). Well, long story short, it's been 4 months and I can't get the thing running right and it's about time I start looking at other options. I am no carb tech by any means and so it is highly possible the Nikki and intake I have work fine, but they are clearly at least somewhat stripped, incomplete pieces anyway. My biggest issue is trying to rematch a modified stock carburetor back to a semi-stock system, I am having trouble even identifying what is gone and what I would need to return it to stock and if that's even worth it.

At this point I want to know my other options and what someone with a bit more experience would do? Do I get a different, more appropriate size of Holley (or other aftermarket company) to mate with the RB manifold? Do I try adjusting and fiddling with the Holly I have and just send it as is? Do I keep fiddling with the Nikki? (I don't particularly like these options, and at this point would rather start somewhere fresh and at least know that I have a working unit in my hand before install with at least some install guide).

So, what would y'all do? New carb and what type - maybe even a refurbished Nikki?

At the end of the day I just want to be able to drive and enjoy the thing - it's never gonna be a stock car again so I really don't care about that. I want a reliable car that I can also get some good miles out of on the weekends. (PS I live where it gets cold and this is a street car so I want to avoid those people out there who are going to try and tell me some sort of racing-oriented setup that must be precisely tuned based on ambient barometric temperature and **** like that.)

lordcupkake

Oh, also forgot to add - the relevant supporting mods already on the car are a Holley electric fuel pump, an MSD ignition setup and definitely some emissions garbage has been deleted. I can't say exactly for sure as most of the mods were done by a previous owner (I know I dug my own grave on this one - this is what happens when you buy your first project car and you weren't quite prepared). I also have smaller mods like an electric rad fan, but those aren't that important.

Qingdao

iTrader: (3)

Fiddle with the nikki more... that's what I'd do.

Have you put the nikki on the engine yet? Do that and run fuel pressure to it. You might be surprised; it might just work.

Qingdao

iTrader: (3)

BUT to be honest with you and to put myself in your shoes.... You say you don't want to mess with the nikki, then you should try to make a spread bore carb work on your engine.

Many years ago, before I became under the belief that NA rotaries should be anything other than peripheral ported, I wanted to try a Rochester carb. Makes perfect sense for a rotary. Small primaries, then WAMO gigantic secondaries. If you have a holley manifold a spread bore carb is as easy as finding an adaptor to bolt it on.


Your best bet is still the nikki, though.

lordcupkake

Okay. No I'm not set on ditching the Nikki, in fact I bought the car knowing I'd probably have to go back to the Nikki at some point. I'm honestly having a harder time just making sure the Nikki is back on the car properly. With all the vacuum lines and solenoids and whatnot that goes into them getting one partially stripped and trying to mate it to my system has been tricky.

Is there anyway there is like a carb installation guide or part of the FSM that details installation of a Nikki? I personally have not been able to find said resource and would love to know where to look.

Maxwedge

iTrader: (1)

Some good pictures of the Nikki would show the gurus what you are starting with. Also the aftermarket fuel pump will put out too much pressure for the Nikki. You'll need a regulator to get it down to 2.5 - 3 psi range (that Holley runs about 6-7).

Benjamin4456

Do you know how long the Nikki has been off the car? There's always a chance it might need a rebuild, which honestly isn't that difficult so long as your willing to learn as you go. Just to clarify though, I wouldn't rebuild it until you've gotten to a point where you can't get it running right. Unfortunately with the PO's rats nest delete, there really isn't telling what sort of set-up issues you might run into. A few pictures would be helpful so we can see what's left of the emissions stuff and to assess the current situation.

I don't know if there is a specific part of the FSM that details the installation of the Nikki, although typically if there is a section about the carb (which there is an entire manual solely for), at the end it just says to reverse the process for re-installation. foxed.ca usually has the manuals, although I've been having some trouble accessing them recently. While not as comprehensive, wright-here.net also has some of them too. If you can't find one for your year, just realize that the installation process is essentially identical between all of the carb'd 7's. Really the only differences will be the smog stuff, of which it sounds like you may be missing some of anyway. Being a Cali car will also make a difference, although I would doubt you have one being over in Ohio.

Best of luck with the Nikki.


Edit: When someone types faster that you...

lordcupkake

I have a regulator, forgot to mention.

Here's a pic of the intake manifold(s) I have https://drive.google.com/open?id=1S1...Vb3wMS_e0uFnes (I believe the smaller one is an SA manifold if I was informed correctly)

Here's a pic of the Nikki: https://drive.google.com/file/d/1WEz...ew?usp=sharing I can get more if anyone wants to see anything specific

Benjamin4456

You are correct that the smaller manifold is an SA (further away in the photo); the other is an FB.

That carb is interesting. It is most definitely not an FB, and is most likely an SA although personally I have not seen that 90 degree fuel inlet before. I'm sure others have though, and will probably know exactly what it is.

Assuming that is a normal SA carb here's what looks like has been removed. There is a missing solenoid that would mount on the vacuum pot for the secondaries. You don't need it but if the intake still has the ACV (air control valve) you'll need to plug the vacuum nipple with a cap - it will be facing upward on a round diaphragm looking thing on the ACV. I'll be able to help more with the vacuum line routing once I can take a look at my SA carb again (probably tonight).

The only other thing that jumps out at me is that on the far right of your photo, you will notice a spring covered in a black shroud. That spring is attached to the 'teeter-totter' and there should be another linkage on the other side. The linage I'm referring to has a T-shaped nut and needs to go over the other side of the teeter-totter (don't adjust the nut). I typically use needle nose pliers to grab the linkage while holding the teeter-totter by hand. Other than that it looks like you might be missing your TPS, but it doesn't do anything when you don't have the emissions rack anymore.

Beware that if you use the SA manifold on the later year engine, there is an exhaust port that will be exposed and will cause lots of noise and exhaust gasses to be flung into your engine-bay. Speaking of engine-bay, could you post a picture of the remaining rats nest? Also a photo of the other side of the carb would be nice.