JeffG

Oops I posted a technical message in the Introduction area. My bad.

Anyway. Looking for suggestions on my son's 85 12a manual RX7 on making it more reliable i.e. starting and drivability. Problems now appear to be that massively complicated stock 4 barrel. There has to be an easier solution for this setup.

Any suggestions welcome.

Thanks
Roy
Kansas City area.

farberio

iTrader: (7)

12a's are very reliable, they almost always run.

Is there a problem with your son's car?

JeffG

Thanks for the response.

The car is "fairly reliable". We installed a header, new cat, and new muffler on it as the old one was trashed. The biggest problem now is the carb is a pain to work on. He had a spare one he rebuilt but the new floats were $100, the rebuild kit was $60 and it's a whole day or more of work to just replace one and if it's a bad rebuild another day to go back. When the accelerator pump started leaking we took the pump off the rebuilt one and replaced it. (that took 6 hours alone given how it's located)

He's hoping a standard carb like a Holley with all the non essential lines, hoses, pipes, and linkages would be more dependable.

When it's mechanically sound he plans to start on the exterior and interior.

Thanks again,
Roy
KC

hanman

Don't even think about a Holley if you are looking for simplicity. The stock Nikki is very easy to work on and rock solid reliable.
If you want it rebuilt right, search out the name Sterling here on this site. He does fantastic rebuilds/performance mods, and your carb will be set up right for you. You might need to play with the jetting but that's about all.

If you get rid of some or all of the rat's nest it makes it a little simpler. And if you put allen head screws in the top of the carb it helps. I am not sure why you are having problems with the carb. I can reset the floats or change jets in a matter of minutes with no hassle at all.
What are you experiencing?

hanman

By the way, you can buy parts at Black Dragon in Kansas City, pick them up yourself and save the crazy shipping costs.
Two new floats from them are $70
FYI.

JeffG

I found the floats at a carb rebuild site. Didn't try Black Dragon as they didn't have that listed in their catalog.

Mainly his issues are hard starting in the winter even with manual choke. Poor fuel economy which may have been the accelerator pump that we finally fixed. It's just such a large rat's nest of hoses and tubes and his air pump is disabled and I believe he's blocked off the EGR line as well.

He'd also like to gain some performance over the stock 12a but dependability is key.

Thanks for the responses.
Roy
KC

hanman

They are listed in the catalog, I just looked them up, but whatever.
Acc pump may be part of the starting problem. He does pump it a couple of times before trying to start it right?
Here are some links to help you:
http://www.mazspeed.com/carburetorfacts.htm
http://maz_tutorials.ten15.net/Tutorial_1.pdf

For performance:
Header
Sterling carb
exhaust
Cold air intake
street ported engine (requires a complete rebuild $$$)

hanman

I will tell you that properly operating the Nikki carb with the stock choke will start very easily until you get to around zero degrees outside. Below that I had a VERY hard time getting mine started. In KC you shouldn't see too much of that kind of weather.

JeffG

Thanks hanman for the information.

I checked out the mazdaspeed link and they mentioned that YawPerformance would rebuild and upgrade a stock Nikki carb but that FAQ looked old and the Yaw site looks to only deal with turbos now.

Any ideas on who can rework a Nikki. We have a spare one we could send for a rework.

Thanks again for the reply.
Roy

PS I'll do a better job of looking at the Black Dragon catalog next time.........

Iwantagofast

iTrader: (9)

How does the Holley compare to a Sterling in regards to tuning, reliability, fuel economy, and HP? I mean as far as looks go Sterling has it hands down.

hanman

Yea, Yaw doesn't do carbs anymore. I got one before he quit and I love it. Do a search for Sterling, he is the guy with the Nikki majic now.
Holley carbs are a PITA, and are not well built. They can produce some good hp numbers, but are a pain to setup and get tuned, and you need a new intake manifold, along with some way to hook up the oil metering pump.