'83 & '84 Hitachi carb mess

[TajMan]

I call it a mess because thats what it is with the stock vacuum lines, what a rats nest.

 

 

I'm driving my '83 Brat, its had about everything eliminated emissions wise, and it is NOT set up in the ideal way. Some things are capped and some things are venting open atmosphere, which prob. should not be that way.

Sometimes I smell gas, can run real rich sometimes like maybe after I start.

Sometimes I have a mid-throttle miss that feels like I'm running out of gas, but if I go WOT then it pulls fine. Could that be a possible vacuum leak in the diaphragm that works to open up the secondaries?

Should get better MPG.

Sometimes hard to start when cold, I have to keep cranking and stabbing throttle for a bit until enough gas gets to carb.

pardon my seemed ignorance

 

 

I have this blue '84 Brat parts car that I just purchased. It always fires up very quick when you try to start, and seems to perform like a stock car should.

 

I want to swap everything directly over to my black car the '83, but it can't swap directly because

A. - exhaust thing has been eliminated that brings the exhaust pipe up exiting from cyl head for emissions stuff. What is that air injection system? I should be fine there where I can keep a few lines capped.

My charcoal canister is eliminated, I can put the one from blue '84 car back on black '83 car if I need.

and,

B. - devices are different, located in passenger's corner of engine bay against firewall, which have to do with carburetor vent lines.

'83 has 2 lines going to black things in pic with electrical connectors, and the '84 has a strange box in that corner I'm not sure what does, has 3 of the carb vacuum lines running to and from it.

 

here are some pics

 

eliminated '83 engine bay:

passenger's firewall corner with vent lines going to these 2 things with electrical connectors:

 

and the stock '84:

here is the strange device THAT car has in the passenger's firewall with vent lines going to/from:

stock rats nest of vacuum..

I won't be needing these anymore with no air injection system

 

any advice would be greatly accepted, and tomorrow I'm just trying to carefully label lines and swap everything over onto my black '83 I drive.

[bheinen74]

Good luck.

looking at those detailed pics of the nasty rats nest of vac lines,now i am so glad i went with a Weber on my Brat. I still kept the rats nest of stuff its on a shelf.

 

the stuff you are noticing different could it be one car had AC and the other no AC? maybe one is CA spec and the other not as well.

Edited September 16, 2011 by bheinen74

[ferox]

There is definitely no need to swap all that crap. I run a simplified stock Hitachi set-up in my Hatch, but both of my digital cameras are not working right now. I might pick up another one today. If so, I'll post a photo of the set-up you need.

 

If you haven't torn it apart yet, I would suggest buying all new vac and fuel lines and replacing what you need one hose at a time, and figure out its function at the same time. Leave the system intact in the '84 and copy it with new hose in the '83...unless it's too late already.

 

From memory, my intake manifold has

 

• vac to heater fan controls
  
• vac to choke pull-off (the hose has a brass orifice restrictor pebble in it so make sure you keep that if you replace the hose)
  
• emissions canister is fully hooked up (purge line w/ check valve back of intake)
  
• PCV system
  
• vac to brake booster
   
  
• ported vac from carb to timing advance
  

I think that's it. Everything else goes away.

 

Check the function of your EGR valve. They are getting expensive and somewhat difficult to find now, so it's your call if the ones you have aren't working properly. You can pull it and make a plate to cover the holes if you want, but if it works I would leave it on.

[Dirk]

My setup.

Sorry pics are up the wrong way. Not sure why that happened.

[TajMan]

Well shoot, I did this yesterday.

I swear I spent like 5 hours+ from start to when I was driving my car again.

I swapped EVERYTHING from the 84 onto the 83, and converted things that were different.

Kept all stock routing and emissions stuff, air injection system is only thing missing.

I bet the 1 year difference and auto-manual difference made up the biggest differences..

 

 

 

Starts way quick every time now just like the blue car did. Feels like a completely different engine now. Smooth and more refined in some ways, but mostly I just think it sucks because the throttle response is dead now!

 

I've experienced at least 3 different carbs and 3 different exhaust setups on Brats.

I love the weber.

I miss the instant-TQ streetfighter I've been driving sometimes.

 

This engine still seems like a slight freak at high-RPM breathing though, better than other engines, probably cyl head casting differences. Loves to make HP and keep pulling more from 4,500 - 5,000 rpm like a little race motor.

 

I swapped on the 84 carb, but it was more filthy, and I know exactly how it performs now. I think I'll swap the other carb I had back onto the 83, keeping all routing the same, see if any difference.

That wasn't the original carb on it anyway, THAT was from a different 84... so i have (2) 84 Hitachi carbs

[Greenley]

I'll post a photo of the set-up you need.

 

Interested in your setup, Ferox.

When you get a chance, please do post the photo.

 

... cheers.

[ferox]

Interested in your setup, Ferox.

When you get a chance, please do post the photo.

 

... cheers.

 

I finally got one of my cameras back from the repair center. If you want more specific photos let me know.