Rebuilding a 280zx Electronic Distributor

[gav240z]

Hi Everyone,

I found this article and thought it would be a good start for anyone looking to rebuild their distributor.

 

http://www.jrdemers.com/280ZX/distributor/distributor.html

 

Also found this article on replacing the E12 module (since these give up the ghost and are expensive to replace) with cheaper readily available GM parts.

http://www.zhome.com/ZCMnL/tech/gmhei.html

 

If someone can document a full distributor rebuild I'll make it a sticky instead of this, but for now this should do.

[sexual_sushi]

I'm about to do 2 so I'll document them but I'm pretty much just following tutorials from other sites like the one you listed and this one:

http://www.atlanticz.ca/zclub/techtips/distributorrebuild/index.html

 

 

[gav240z]

I'm about to do 2 so I'll document them but I'm pretty much just following tutorials from other sites like the one you listed and this one:

http://www.atlanticz.ca/zclub/techtips/distributorrebuild/index.html

 

Even better, that is a great tutorial. Very detailed photos and explanations. The 1 thing I still don't understand is the role of the ball bearings. I recall when I rebuilt mine (with some help) that we welded it together so it wouldn't rotate anymore. I'm not sure what effect this has on the way the distributor works?

 

Also we disabled the vacuum advance because the diaphram's were stuffed and we couldn't find 1 that worked.

 

Also the plate in the distributor where the weights attach to, if you modify it like with a dremmel piece you can get more advance. Various Datsun's and their distributors have different plates, weights and springs. You can mix and match to get the desired amount of mechnical advance you want. We did this with my distributor and it made an amazing difference in the way the car behaved - I couldn't believe what an animal it became .

 

So my tips are:

Go to a junk yard, find as many different types of L-series distributors as you can (4 and 6 cyl versions) and pull them apart for their weights and advance plates. Mix and match to get desired advance. Unfortunately at this stage I can't give advise on what weights to use or what plates and their numbers, but I'm sure if you experiment a bit and use a timing light you can find out what kind of advance you are getting.

[peter mc]

hi i have found most L engines that i tune on the dyno like 14 deg initial advance and 28 deg total  more timing hurts power in most  hope this helps

[sexual_sushi]

the 1 thing I still don't understand is the role of the ball bearings.

 

Please take anything I say with a grain of salt as I am just learning about dizzys. Hence why I want to rebuild the ones I have so I can know more about them.

 

I believe this is part of the vacuum(?) advance. The suction that pulls on the diaphram pulls an arm attached to the breakerplate assembly. The bearings allow the breaker plate to rotate giving you your advance?

 

I read of a guy who made his own housing for the bearings (the brittle plastic part that always breaks) and he said the differences in tolerances had an affect on how easily the plate rotated which changed the amount of advance it gave. This could be a good or a bad thing I suppose.

 

So you can play with the mechanical advance by adding/subtracting weight. Apparently the difference in the weights that came with the dizzys was from the manual to auto cars. 8.5 was stamped on the weights that came in the manual cars and 9 was stamped on the autos. (The one infront of me atm has 8.5)

 

For the vacuum advance, apparently you can adjust the vacuum arm range with a screw. Apparently this differed for different years and I believe the actual size of the dashpot also changed throughout the years.

 

I suppose all of this means you need to know exactly what your advance is currently doing and what you want it to be doing!

 

I'm sure there are a few guys on here that know a lot about dizzy's so feel free to correct anything

[sexual_sushi]

Found the link from where I got most of this info:

 

http://pape.ws/allan_and_rosanne/Z-Car_Stuff/Bryan-Little/Datsun%20L6%20Performance%20Tips.htm

[MJC]

Can anyone please help with my inability to source a 280ZX distributor module in Australia, or if not Over seas?

[dimedriver]

Get a GM HEI ignition module.  They should be pretty common world wide.

About $30US.  The nissan one is $250 new here and they nearly never go bad.  Check that you ground your dizzy body.

 

 

Info on sourcing the GM HEI module.

http://www.megamanual.com/ms2/GM_7pinHEI.htm

You want the 4 pin version.

Should be on most GM cars and trucks from 70 to about 85.

follow these instructions too install.

http://www.zhome.com/ZCMnL/tech/gmhei.html

 

-Dime

[Zedman240®]

Can anyone please help with my inability to source a 280ZX distributor module in Australia, or if not Over seas?

 

You should be able to retrofit a common Bosch "022" module with just some wire extensions and some connectors. Easy to wire up and cheap and plentiful!

[MJC]

Thanks for the help fellas, I will check it out, I think the whole Dissy is shot, and at $260.00 for a new one from the states they look pretty good.

[dimedriver]

Hey these are pretty hardy dizzies.  Can you post some pictures?

 

I have seen them work when still in really bad shape.

It should also be pretty easy to find bearings for.  I think most of them are some form of standard metric bearing probably not as common as the 608 but pretty common.

 

The red and green wires that the module connect to should produce an AC voltage when you spin the dizzy.  This voltage should climb with speed.  Try chucking the end of the dizzy in a hand drill and checking what the voltage is when it spins it.  Do this with the dizzy out of the car.

 

Oh I also made a video using the GM HEI module with a 280zx dizzy and coil.

 

-Dime

[dimedriver]

There is an exploded diagram of the dizzy

http://web.archive.org/web/20010702093053/www.physics.ohio-state.edu/~jrdemers/280ZX/distributor/D79.gif

another one

http://www.atlanticz.ca/zclub/techtips/distributorrebuild/index.html

 

specs for quite a few of them can be found here.

http://web.archive.org/web/20050308055504/home.att.net/~jason510/dizzy_specs.htm

 

 

Oh and a rebuild how to.

http://web.archive.org/web/20041207181339/www.jrdemers.com/280ZX/distributor/distributor.html

 

-Dime

[jamo240]

Hey team

 

A bit of theory on distributors for anyone who might be wondering. The ability of the breaker plate (the plate the ign points are screwed onto) to move relative to the distributor housing via the vacuum servo is how the dizzy modulates ign timing wrt engine LOAD. The ability of the cam that opens and closes the ignition points to move relative to the dizzy drive shaft is how the dizzy modulates ign timing wrt engine SPEED. The load side of the timing 'map' is there to advance timing when the cylinders are not filling as efficiently, which is when we're cruising at highway speeds, with lots of manifold vacuum (ie only part throttle opening)...this is essential to achieving good fuel consumption. The speed side of the timing map is there to advance timing as the engine speed increases, and there is less time for the fuel charge to burn...this is essential to increasing power as the engine speed increases, so that maximum cylinder pressure is being achieved throughout the power stroke.

 

To disable the load side of the dizzy will mostly affect everyday driveability and especially fuel consumption. To disable the speed side of the dizzy will mostly affect driveability and power.

 

While you can fiddle around with a timing light in your back yard and all that, it is impossible to set a dizzy up properly in a car without a dyno to load up the engine, and effectively superimpose the effects of load and speed on the distributor to understand what the timing is across the engine operating range. This is a job best done by an auto electrician/engine man who has a distributor test bench...they mount the dizzy on the bench, which can run through the full speed range while applying vacuum as well, and therefore work up the whole picture for you. They will mess around with spring tensions, advance weights to get not only the total advance where you want it, but also develop the curve between the setting at idle thru to full power. This is driven by compression settings, cam timing/profile, exhaust and carburettion etc.

 

The very best set up is to go to someone who has a chassis dyno and a dizzy bench, and they will get the whole thing setup to give max power thru the rev range, good driveability and good cruise/fuel consumption as well. You can then decide which of these you want to compromise on depending on what you're using the car for.

 

CHeers

 

 

Jamo

[Wayne G]

What RPM is total in by Peter?

[MaygZ]

hi i have found most L engines that i tune on the dyno like 14 deg initial advance and 28 deg total  more timing hurts power in most  hope this helps

 

What RPM is total in by Peter?

 

Just in case anyone else finds themself saying "WTF?"

 

I suspect that he wants to know at what RPM one should have 28 Deg of advance.  Of course you will have the higher advance when you close the throttle at speed, thus creating the most manifold vacuum and therefore the most advance.

 

Shiver I hope I'm right.  Afterall nothing lets you down more that being wrong when being a smart arse 

 

Now I'm second guessing myself - mechanical advance and vacuum advance do work cumulatively, don't they?

[jamo240]

Ha! Nice limb climbing MaygZ, but yes, you're right, they work cumulatively, and completely independently of each other.

 

So yes, once you've got full centrifugal advance in, and then get off the throttle at speed, you'll get full manifold vacuum, and hence maximum ign advance....fortunately, under those conditions you need about 1.27hp to keep things turning over, and there is so little in the cylinders, that stacks of spark can't do any damage!

 

Jamo

[dazzed]

Hey team

 

A bit of theory on distributors for anyone who might be wondering. The ability of the breaker plate (the plate the ign points are screwed onto) to move relative to the distributor housing via the vacuum servo is how the dizzy modulates ign timing wrt engine LOAD. The ability of the cam that opens and closes the ignition points to move relative to the dizzy drive shaft is how the dizzy modulates ign timing wrt engine SPEED. The load side of the timing 'map' is there to advance timing when the cylinders are not filling as efficiently, which is when we're cruising at highway speeds, with lots of manifold vacuum (ie only part throttle opening)...this is essential to achieving good fuel consumption. The speed side of the timing map is there to advance timing as the engine speed increases, and there is less time for the fuel charge to burn...this is essential to increasing power as the engine speed increases, so that maximum cylinder pressure is being achieved throughout the power stroke.

 

To disable the load side of the dizzy will mostly affect everyday driveability and especially fuel consumption. To disable the speed side of the dizzy will mostly affect driveability and power.

 

While you can fiddle around with a timing light in your back yard and all that, it is impossible to set a dizzy up properly in a car without a dyno to load up the engine, and effectively superimpose the effects of load and speed on the distributor to understand what the timing is across the engine operating range. This is a job best done by an auto electrician/engine man who has a distributor test bench...they mount the dizzy on the bench, which can run through the full speed range while applying vacuum as well, and therefore work up the whole picture for you. They will mess around with spring tensions, advance weights to get not only the total advance where you want it, but also develop the curve between the setting at idle thru to full power. This is driven by compression settings, cam timing/profile, exhaust and carburettion etc.

 

The very best set up is to go to someone who has a chassis dyno and a dizzy bench, and they will get the whole thing setup to give max power thru the rev range, good driveability and good cruise/fuel consumption as well. You can then decide which of these you want to compromise on depending on what you're using the car for.

 

CHeers i dont need a dyno to do that i can do that with my eyes shut just tell me what engine you have

 

 

Jamo

[zed4ps]

Hi, i have bought 2 dizzies from people and both have broken breaker plate assemblies. anyone know where to purchase them. Cheers Peter

[Groundhog]

I have a 280ZX Series 2 electronic distributor that I am chasing a few parts for.
Is it still possible to buy a reluctor and bushing locally?
From what I can see on EBay it is possible to buy an ignition unit or change to a GM one.
I am well capable of overhauling it myself provided I can get the parts.

 

https://www.google.com.au/search?q=280ZX+distributor+reluctor&client=firefox-b&tbm=isch&imgil=uT1qa_0UMoMdwM%253A%253BM2YSwSCQc8lz_M%253Bhttp%25253A%25252F%25252Fwww.oreillyauto.com%25252Fsite%25252Fc%25252Fsearch%25252FDistributor%2525252BReluctor%25252F02804%25252FC0334.oap%25253Fyear%2525253D1979%25252526make%2525253DNissan%25252526model%2525253D280ZX%25252526vi%2525253D1209293&source=iu&pf=m&fir=uT1qa_0UMoMdwM%253A%252CM2YSwSCQc8lz_M%252C_&usg=__5EJ-w2UnAm4FbrurnUsZ0kd5wn4%3D&biw=1920&bih=947&ved=0ahUKEwics_2xqazNAhVBE5QKHeorBGYQyjcIUA&ei=a31iV9zRFcGm0ATq15CwBg#imgrc=uT1qa_0UMoMdwM%3A

Edited June 16, 2016 by Groundhog

[Groundhog]

Before and after photos of the ball bearing keeper under the vacuum advance plate.

Before

 

After- nearly finished.