Hitachi Carburetor alternatives

[tylertrend]

Here's the backstory: The carb I'm currently running on my EA81 in my Coupe I pulled off of an '81 brat in a junkyard along with the manifold. My unit says its a DCP 306-16/304, has manual choke and a vacuum secondary. The venturi sizes are  20/27. The only reference I can find to a carb like that is the Hitachi unit from Nissan A12 engines from the 70s. My setup has a small flat spot in the acceleration which has had me looking at how to remedy that. I am going to try raising the float level a smidge or maybe getting some slightly larger jets. I think this carb can run this engine properly it just needs tuned a bit more. It's pretty close as it is. The carb for the Nissan A14 engines is larger, I believe** its a 23/27, don't quote me on that. If I cannot get mine where I want it to be, I will get the A14 carb and see how it works. All the Nissan spec carbs have mechanical secondaries which is nice too, and manual chokes. 

The main point of this whole story is that I have found new A12 and A14 carbs (Hitachi design, just like the stock EA carbs) online for $40-$50. If these work satisfactorily this could be a cheap way to get a car running again and look stock, no worries of sloppy throttle shafts, and no expensive Weber swaps with stupid looking air filters. I will report back with more info and testing. Anyone tried this already?

Edited December 4, 2019 by tylertrend

[Steptoe]

A link to share please?

[tylertrend]

https://www.amazon.com/Dromedary-Carburetor-Datsun-Pulsar-16010-H1602/dp/B074C68D2D

https://www.maxpeedingrods.com/Carburettor-Carb-Fit-for-Nissan-A14-engine-Pulsar-1977-1981-16010H6100.html

Basic google search also turns up plenty of options. I prefer the A14 carb because the choke cable runs in from the back, not the front like the A12 (I know, first world problems). All these units have basically no emission control ports, just ported vacuum for the disty. 

Here's a link to jets and other parts if need be.

https://jetsrus.com/a_jets_by_carburetor_type/jets_hitachi_main_4H7.html

Edited December 2, 2019 by tylertrend
Added Link

[Steptoe]

I looked at maxpeedingrods one - might be good source for Hitachi idle cut solenoids alone

 

Thanks for sharing

[Subarule]

I think all the Hitachi carbs in vintage Subes have a flat spot. I got the Weber and never looked back. What a difference!

[tylertrend]

Mine's got a pretty bad one. I'm trying to make it a little better through tuning. 

[Subarule]

If you're going to drive your Sube for a long time, spread the cost of a Weber over the years. For instance, say a Weber is $350 and you can and do drive the car for 7 years (an example). $350 divided by 7 years is $50 a year. Pretty cheap for the power & reliability you get from the Weber.

[DaveT]

Everything I have read on this forum, over many years, points to forget about the Hitachi. 

[el_freddo]

11 hours ago, Subarule said:

 I got the Weber and never looked back. What a difference!

I got an EJ22 and NEVER looked back. What a night and day difference!! 

Plus the EJ is uber reliable! 

Cheers 

Bennie

[GeneralDisorder]

Subaru and Nissan use different Weber adapter plates so I conclude it will not fit. 

Besides. Stock Hitachi carbs have too much extraneous plumbing and smog related equipment. 

GD

[charles_thomas]

It just might. Somewhere on this site... Although A quick search didn't yield it, Is a blurb about using either an old datsun or nissan adapter for the EA82. It is a slightly taller Single piece adapter. It is very possible that there is another one for the EA81.

So do your own research and let us all know if you found another workaround. Despite some members insistence things don't exist, this board finds a whole bunch of work-around and replacement parts off other engines. For example, the smaller stock weber of the late 70's fiat is a bolt on to the EA82, but no-one really seems to bring it up as an option. 

So-

 First find the base plate bolt spacing dimensions for the carb you want to use, and the ea81 and see if they are the same.

Second thing to look for is the tilt. Subaru manifolds sit level on top of the engine, which means the adapter needs to be pretty close to level as well. Some of the inline engines use a tilted back manifold, it will often cause fuel float issues to run that adapter on the subaru. 

Good luck, do please keep us informed.

-Charles

[GeneralDisorder]

Not that you couldn't (easily) make one. But dear god.... WHY? That stock Hitachi junk is exactly that - JUNK. You get what you pay for and it's not impossible to fit a weber under a stock appearance air filter. 

GD

[wagons]

@tylertrend the datsun adapter you are thinking of is a Transdapt 2107. This adapter flange fits the EA82 and adapts to a weber. I know because i use this exact one. I picked up a used Weber for $50. My weber passed emissions in Phoenix AZ, run it lean at first (almost scary lean). Hitachi carbs are absolute crap and most carb shops will not take the time to rebuild one (never work properly after a rebuild). I have a chinese weber copy i will send you if you pay for shipping. It ran well but its not a REAL weber. 

[Subarule]

No doubt just anything can be kluged together to make an old Subaru run. I picture someone the car has been sold on to trying to work on it and after getting under the hood going "What the......?? Just one more Frankensube.