Confused with EA81 Disty

[ettev]

OK, I know there are tons of threads covering all sorts of questions and issues with both the Nippon and Hitachi distys, so no need to lecture about searching. I've done that and I'm still perplexed. The latest undertaking is a 1984 EA81 GL 4WD Wagon. What's got me thinking.....this thing appears as if it's equipped with the Nippon distributor (vented cap). I thought the Nippon's were only in the 2WD (front wheel drive) models? What vehicles actually got which distributors? Just so I'm correct in my thinking its a Nippon, apart from the vented cap what's a quick visual to determine Nippon vs. Hitachi? Also, I've read that the disty's may have been matched up with carb manufacturer. I'm planning on a Weber carb swap, so if this thing is a Nippon disty am I in for any issues that I should be aware of going in? As always, thanks in advance for any help you folks can post.

[GeneralDisorder]

For EA81's it's Hitachi on 4WD's and ND on 2WD's.

 

You can see pictures of both on my SPFI write up page at:

 

http://home.comcast.net/~trilinear/EA81_SPFI.html

 

Either one works fine with a Weber. You shouldn't have any trouble in that regard.

 

GD

[edrach]

GD is right on the money with all that information. No probleme with either disty and a weber.

[ettev]

Now I'm really confused. From what I can tell this is a Nippon in a 4WD.

[GeneralDisorder]

Then it was swapped out or the engine was swapped out (seen that before) at some point in the past. No big deal they are basically interchangeable. But you should verify that you have the blue-topped coil (ND) as well. The should match for best results and longevity.

 

GD

[ettev]

But you should verify that you have the blue-topped coil (ND) as well. The should match for best results and longevity. GD

 

GD, please explain the coil/disty match-up. I believe you but I'd just like to know as a point of learning something new why the coil is different and why a mismatch would matter. Are the coils physically different so I can properly identify which coil I have?

 

Then.....is one disty/coil setup better than the other? Why did Subaru use a different setup for the 2WD vs 4WD? If the Hitachi is better is it as simple as finding one and doing the swap or are there other mods/components that need to be swapped?

Edited June 26, 2010 by ettev

[GeneralDisorder]

GD, please explain the coil/disty match-up. I believe you but I'd just like to know as a point of learning something new why the coil is different and why a mismatch would matter. Are the coils physically different so I can properly identify which coil I have?

 

Well - it has to do with the winding resistance of the coil. The triggering amp inside the distributor is a rather sensitive peice of equipment and if the resistance of the coil winding is not what the trigger was designed for you can overload it and cause damage to the electronics. People have done this by installing after market coil's such as those made by Accell or MSD etc. For most cars that use the canister style coil you can get away with it without damaging anything (GM HEI for example) but in the specific case of the Subaru units they don't seem to always handle it (and sometimes they do ) and since there isn't much to be gained by upgrading the coil anyway it's a much safer bet to pair up the distributor module with it's intended coil.

 

The ND coil's have a bright blue top (where all the wires connect), while the Hitachi coils are black all over.

 

Then.....is one disty/coil setup better than the other? Why did Subaru use a different setup for the 2WD vs 4WD? If the Hitachi is better is it as simple as finding one and doing the swap or are there other mods/components that need to be swapped?

 

Better/worse comparisons have been made in the past. Here's what I can tell you:

 

1. The advance curves are the same between the two.

 

2. The ND unit has a slightly higher voltage spark.

 

3. The ND unit's experience more problems with shaft bushing failure.

 

4. The Hitachi ignition module is much cheaper and more availible than the ND - and they tend to fail less often.

 

4. The Orientation of the plugs on the cap makes the ND unit interfere with the choke housing of the Weber less than the Hitachi (but either one works fine).

 

From a performance standpoint there is no difference. Though I can say I've had a lot more problems with ND module failures and shaft bushing failures than I have with the Hitachi units. Personally I prefer the Hitachi because of this.

 

As to why Subaru chose different brands for different configurations - I have no idea. That's equivelent to asking why some models came with that crappy Carter/Weber single barrel. I don't think anyone knows why they did some of the things they did. Could have been something supply chain related like ND/Hitachi couldn't supply enough on their own for all the cars or that ND was located near the 2WD factory and Hitachi was located near the 4WD factory...... we will probably never know.

 

GD

Edited June 26, 2010 by GeneralDisorder

[ettev]

Tremendous info, thanks. How about the swapto Hitachi. In and out, or other mods/changes required?

[GeneralDisorder]

Pretty much just drop it in and time it. No mods needed.

 

GD