Holley carb 12a swap
06-22-15, 09:22 PM
#1
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Holley carb 12a swap
My 85 gs started dying out at stop lights and when I popped the hood I heard what sounded like an air leak coming from the carburetor. And I'm getting really tired of messing with the stock carb. So I'm going to replace the stock carb with a holley. I checked on racingbeat and they sell a whole holley kit with the manifold, carb and filter. Are Holley's good for daily driving even through winter?
06-25-15, 11:26 AM
#2
Sounds like you've already made up your mind but everyone here will tell you the Holley sucks and has no business on a rotary. You can't go hard around corners and you can't autocross with them. There have also been several bum carbs coming out of RB recently due to the Holley factory's poor quality control and poor quality castings these days. Do you really want to take the risk? Plus the kit costs like a grand these days doesn't it?
Back in the '80s when RB developed this kit, Holleys were everywhere so it made sense. That's no longer true these days.
The stock carb, after mods, is much better. It does everything the Holley does but does it better. I've just spent almost a year and half improving the stock Nikki and they keep getting better and better. And this is coming from someone who also has an RB Holley 600 that I've tested in the same car.
With the Holley, you go to slow down and there is a glitch in the idle due to fuel slosh. That never happens with the Nikki. You go hard around a corner, same issue.
The Nikki runs a lot better over all because it was designed for a rotary in the first place. All the circuits work as intended without too many compromises like what RB does to the Holley to get it to run sort of right on a separate runner manifold.
You can grab a cheap Holley off the shelf, grab a carb spacer and cut a channel in the primary side and plunk it down on the RB manifold. This seems to work. I tried this on an Edelbrock and it worked great. Or as well as expected. It still had a massive bog when you'd slow down and turn left, worse than the Holley. Both the Edelbrock and the Holley still were not as powerful as a hogged out Nikki.
The hogged out Nikki and an RB long primary exhaust were powerful enough that it wanted to break both tires loose in a straight line, up a hill, in gear, in warm weather, when the mechanical secondaries were opened. I've never experienced anything even close to that on an Edelbrock on a Camden supercharger or an RB Holley on just a manifold. I didn't have to rev it and dump the clutch. I didn't have to go around a corner. All this power was literally just a flex of the ankle away.
But you've made up your mind, right? Why else would you make a post like this on the forum, other than to provide a way for others to convince you to do something different. Either option requires you to get down and dirty with that side of the engine. Who knows whether you'll discover some kind of problem with one of the stock emissions devices, and upon correcting it, your Nikki will work a lot better. But then it's still a stock Nikki. You won't get any real power out of it until it's modified. You also need a free flowing exhaust like the RB long primary (they call it their "streetport" system). To get any flow out of either intake option. Also need a free flow air filter. Let's not forget a direct fire ignition system because it always improves these cars. Then maybe a light steel flywheel unless you like the stock one. I could go either way these days but I'll stay away from aluminum because it's kinds dumb on the street. Plus aluminum and turbos don't mix, and it's all about the turbos these days. Oh wait we're talking basic NA carb stuff here. I've posted a bunch of stuff for how to mod your Nikki on this forum for pennies compared to the expensive RB stuff. But do what you feel you can do. I won't hold your hand through this process. Good luck!
Back in the '80s when RB developed this kit, Holleys were everywhere so it made sense. That's no longer true these days.
The stock carb, after mods, is much better. It does everything the Holley does but does it better. I've just spent almost a year and half improving the stock Nikki and they keep getting better and better. And this is coming from someone who also has an RB Holley 600 that I've tested in the same car.
With the Holley, you go to slow down and there is a glitch in the idle due to fuel slosh. That never happens with the Nikki. You go hard around a corner, same issue.
The Nikki runs a lot better over all because it was designed for a rotary in the first place. All the circuits work as intended without too many compromises like what RB does to the Holley to get it to run sort of right on a separate runner manifold.
You can grab a cheap Holley off the shelf, grab a carb spacer and cut a channel in the primary side and plunk it down on the RB manifold. This seems to work. I tried this on an Edelbrock and it worked great. Or as well as expected. It still had a massive bog when you'd slow down and turn left, worse than the Holley. Both the Edelbrock and the Holley still were not as powerful as a hogged out Nikki.
The hogged out Nikki and an RB long primary exhaust were powerful enough that it wanted to break both tires loose in a straight line, up a hill, in gear, in warm weather, when the mechanical secondaries were opened. I've never experienced anything even close to that on an Edelbrock on a Camden supercharger or an RB Holley on just a manifold. I didn't have to rev it and dump the clutch. I didn't have to go around a corner. All this power was literally just a flex of the ankle away.
But you've made up your mind, right? Why else would you make a post like this on the forum, other than to provide a way for others to convince you to do something different. Either option requires you to get down and dirty with that side of the engine. Who knows whether you'll discover some kind of problem with one of the stock emissions devices, and upon correcting it, your Nikki will work a lot better. But then it's still a stock Nikki. You won't get any real power out of it until it's modified. You also need a free flowing exhaust like the RB long primary (they call it their "streetport" system). To get any flow out of either intake option. Also need a free flow air filter. Let's not forget a direct fire ignition system because it always improves these cars. Then maybe a light steel flywheel unless you like the stock one. I could go either way these days but I'll stay away from aluminum because it's kinds dumb on the street. Plus aluminum and turbos don't mix, and it's all about the turbos these days. Oh wait we're talking basic NA carb stuff here. I've posted a bunch of stuff for how to mod your Nikki on this forum for pennies compared to the expensive RB stuff. But do what you feel you can do. I won't hold your hand through this process. Good luck!
06-25-15, 11:39 AM
#3
Sounds like you've already made up your mind but everyone here will tell you the Holley sucks and has no business on a rotary. You can't go hard around corners and you can't autocross with them. There have also been several bum carbs coming out of RB recently due to the Holley factory's poor quality control and poor quality castings these days. Do you really want to take the risk? Plus the kit costs like a grand these days doesn't it?
Back in the '80s when RB developed this kit, Holleys were everywhere so it made sense. That's no longer true these days.
The stock carb, after mods, is much better. It does everything the Holley does but does it better. I've just spent almost a year and half improving the stock Nikki and they keep getting better and better. And this is coming from someone who also has an RB Holley 600 that I've tested in the same car.
With the Holley, you go to slow down and there is a glitch in the idle due to fuel slosh. That never happens with the Nikki. You go hard around a corner, same issue.
The Nikki runs a lot better over all because it was designed for a rotary in the first place. All the circuits work as intended without too many compromises like what RB does to the Holley to get it to run sort of right on a separate runner manifold.
You can grab a cheap Holley off the shelf, grab a carb spacer and cut a channel in the primary side and plunk it down on the RB manifold. This seems to work. I tried this on an Edelbrock and it worked great. Or as well as expected. It still had a massive bog when you'd slow down and turn left, worse than the Holley. Both the Edelbrock and the Holley still were not as powerful as a hogged out Nikki.
The hogged out Nikki and an RB long primary exhaust were powerful enough that it wanted to break both tires loose in a straight line, up a hill, in gear, in warm weather, when the mechanical secondaries were opened. I've never experienced anything even close to that on an Edelbrock on a Camden supercharger or an RB Holley on just a manifold. I didn't have to rev it and dump the clutch. I didn't have to go around a corner. All this power was literally just a flex of the ankle away.
But you've made up your mind, right? Why else would you make a post like this on the forum, other than to provide a way for others to convince you to do something different. Either option requires you to get down and dirty with that side of the engine. Who knows whether you'll discover some kind of problem with one of the stock emissions devices, and upon correcting it, your Nikki will work a lot better. But then it's still a stock Nikki. You won't get any real power out of it until it's modified. You also need a free flowing exhaust like the RB long primary (they call it their "streetport" system). To get any flow out of either intake option. Also need a free flow air filter. Let's not forget a direct fire ignition system because it always improves these cars. Then maybe a light steel flywheel unless you like the stock one. I could go either way these days but I'll stay away from aluminum because it's kinds dumb on the street. Plus aluminum and turbos don't mix, and it's all about the turbos these days. Oh wait we're talking basic NA carb stuff here. I've posted a bunch of stuff for how to mod your Nikki on this forum for pennies compared to the expensive RB stuff. But do what you feel you can do. I won't hold your hand through this process. Good luck!
Back in the '80s when RB developed this kit, Holleys were everywhere so it made sense. That's no longer true these days.
The stock carb, after mods, is much better. It does everything the Holley does but does it better. I've just spent almost a year and half improving the stock Nikki and they keep getting better and better. And this is coming from someone who also has an RB Holley 600 that I've tested in the same car.
With the Holley, you go to slow down and there is a glitch in the idle due to fuel slosh. That never happens with the Nikki. You go hard around a corner, same issue.
The Nikki runs a lot better over all because it was designed for a rotary in the first place. All the circuits work as intended without too many compromises like what RB does to the Holley to get it to run sort of right on a separate runner manifold.
You can grab a cheap Holley off the shelf, grab a carb spacer and cut a channel in the primary side and plunk it down on the RB manifold. This seems to work. I tried this on an Edelbrock and it worked great. Or as well as expected. It still had a massive bog when you'd slow down and turn left, worse than the Holley. Both the Edelbrock and the Holley still were not as powerful as a hogged out Nikki.
The hogged out Nikki and an RB long primary exhaust were powerful enough that it wanted to break both tires loose in a straight line, up a hill, in gear, in warm weather, when the mechanical secondaries were opened. I've never experienced anything even close to that on an Edelbrock on a Camden supercharger or an RB Holley on just a manifold. I didn't have to rev it and dump the clutch. I didn't have to go around a corner. All this power was literally just a flex of the ankle away.
But you've made up your mind, right? Why else would you make a post like this on the forum, other than to provide a way for others to convince you to do something different. Either option requires you to get down and dirty with that side of the engine. Who knows whether you'll discover some kind of problem with one of the stock emissions devices, and upon correcting it, your Nikki will work a lot better. But then it's still a stock Nikki. You won't get any real power out of it until it's modified. You also need a free flowing exhaust like the RB long primary (they call it their "streetport" system). To get any flow out of either intake option. Also need a free flow air filter. Let's not forget a direct fire ignition system because it always improves these cars. Then maybe a light steel flywheel unless you like the stock one. I could go either way these days but I'll stay away from aluminum because it's kinds dumb on the street. Plus aluminum and turbos don't mix, and it's all about the turbos these days. Oh wait we're talking basic NA carb stuff here. I've posted a bunch of stuff for how to mod your Nikki on this forum for pennies compared to the expensive RB stuff. But do what you feel you can do. I won't hold your hand through this process. Good luck!
06-25-15, 03:36 PM
#4
I just found this on the forum. Click it, then click the links posted by diabolical1. Interesting stuff that mirrors what we just said. https://www.rx7club.com/general-rota...-carb-1085344/
06-25-15, 08:11 PM
#5
Click it, then click the links posted by diabolical1. Interesting stuff that mirrors what we just said. https://www.rx7club.com/general-rota...-carb-1085344/
i know, right. i was trying to help the poor guy, but nothing i found with any mention of jetting a 465 came without people saying they suck! i think i'll go and see how agreeable he would be to trying to source a Nikki. i know nothing of France and how available parts are though, so i kinda got the feeling he was stuck. i guess we'll see.
on topic ... Buninskies, i don't have the same contempt for Holleys like most, but i would agree that you should get your Nikki modded. if you're getting tired of messing with the Nikki, you'll be even more tired of messing with the Holley. i promise ... and you would have paid a pretty hefty sum to get that tired. the money that you'd spend on that RB system can go a VERY long way to getting a good Nikki or two ... with lots of change to spare. the performance is proven and not only that, but (1) you have tons of support and (2) people are still making progress in Nikki performance.
06-26-15, 10:13 AM
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What kind of carb would you guys suggest for daily use and reliability? Because it seems like every few months this happens where my car can't even run anymore because of the carb screwing up. I honestly enjoy taking my car around corners and I enjoy going fast even though I have an automatic I like to explore my car's limits every now and then.
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06-26-15, 11:26 AM
#8
as i see it ...
scenario 1 - the carb is not the culprit. there is something else wrong (vacuum leak).
scenario 2 - the carb is the culprit. rebuild it or rebuild it AND modify it. either way, i am convinced it's the MOST reliable choice as far as running on a stock 12A because it was designed for it (as someone mentioned before). if you don't/can't do it, then find someone who can. i'm not a guru or expert, but i do have carburetor experiences (Nikki, Holley and Dell'Orto) and i can tell you for sure the Nikki is your best bet because if you find working on it frustrating, you're probably not going to like working with something out of a box even more.
scenario 1 - the carb is not the culprit. there is something else wrong (vacuum leak).
scenario 2 - the carb is the culprit. rebuild it or rebuild it AND modify it. either way, i am convinced it's the MOST reliable choice as far as running on a stock 12A because it was designed for it (as someone mentioned before). if you don't/can't do it, then find someone who can. i'm not a guru or expert, but i do have carburetor experiences (Nikki, Holley and Dell'Orto) and i can tell you for sure the Nikki is your best bet because if you find working on it frustrating, you're probably not going to like working with something out of a box even more.
06-26-15, 01:54 PM
#10
Leave the stock needles and seats alone. Otherwise you'll get flooding problems. Also leave the floats at their stock adjustment.
A rebuild kit will come with new needles, seats and a ruler for setting float heights. Ignore these parts.
You will also notice the new base gaskets. The one that fits between the cast iron baseplate and the carb main body is very thin and prone to leaks. Go ahead and use it but consider making a new gasket out of thicker paper using the one from the kit as a template. That's what I've needed to do.
The accel pump diaphram can be changed. The new ones are the long travel style but work ok in place of the short travel accel pump housing like you have.
If the site glass windows are not disturbed and no leaking, they can stay in place, but if you see any evidence of leaking, you can swap in new o-rings and gaskets from the kit. The gaskets are usually oversized and will crumple a bit unless trimmed slightly.
The air horn or top gasket has screw holes that aren't quite right. A small bit of correcting with a small hole punch (1/8") or a razor blade will work. It can also be really tight around the seats. Maybe some trimming is required and maybe not.
There is no altitude compensator gasket in rebuild kits so try not to remove it from the air horn. However if the air horn is really dirty and you want to clean it, well, I'll leave that up to you.
The rebuild kits can be found at rockauto for about 30 bucks plus 7 shipping.
A rebuild kit will come with new needles, seats and a ruler for setting float heights. Ignore these parts.
You will also notice the new base gaskets. The one that fits between the cast iron baseplate and the carb main body is very thin and prone to leaks. Go ahead and use it but consider making a new gasket out of thicker paper using the one from the kit as a template. That's what I've needed to do.
The accel pump diaphram can be changed. The new ones are the long travel style but work ok in place of the short travel accel pump housing like you have.
If the site glass windows are not disturbed and no leaking, they can stay in place, but if you see any evidence of leaking, you can swap in new o-rings and gaskets from the kit. The gaskets are usually oversized and will crumple a bit unless trimmed slightly.
The air horn or top gasket has screw holes that aren't quite right. A small bit of correcting with a small hole punch (1/8") or a razor blade will work. It can also be really tight around the seats. Maybe some trimming is required and maybe not.
There is no altitude compensator gasket in rebuild kits so try not to remove it from the air horn. However if the air horn is really dirty and you want to clean it, well, I'll leave that up to you.
The rebuild kits can be found at rockauto for about 30 bucks plus 7 shipping.
07-16-15, 03:34 PM
#13
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I have a street ported 12a with a holley on it but this thread has talked me into pulling the Nikki carb out. Is there anything to look out for before i get started?
02-02-18, 01:03 PM
#14
82 GSL Leaky Carb
Sorry to revive an old thread, but I am new owner of an 82 Gsl, running bone stock 12a, passed CA smog with the carb dripping gas from the throttle pump, i have the gasket set, i have rebuilt a TBI system before, but this seems more complicated. I called my local carburetor rebuild shop trying to have the carb professionally rebuilt, because it isnt a Holley, Edelbrock or a Rochester, they dont want it. I can probably R&R the carb and rebuild it, but it wont be any better, How would i go about hogging the Nikki carb? and will it still pass smog with a modified Nikki? We have a holley carb that was already rebuilt, I could get a RB manifold and slap it on, but its a 650 tuned for a V8 Race motor, definitely not for rotary. I would prefer to keep things as stock as possible, as i will have to pass emissions again in a year or two.
The Nikki leaks fuel on the exhaust right now, so it is no longer safe to drive. Any Suggestions are appreciated.
The Nikki leaks fuel on the exhaust right now, so it is no longer safe to drive. Any Suggestions are appreciated.
09-24-19, 10:19 AM
#15
Junior Member
don't swap back the holley gives more power, just remember to premix if its not already modded for the omp, the nikki is over complicated and harder to work on, also with a holley you get support from another group of people and sources, unlike the ultra rare nikki.
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