260Z to 280ZX distributor

[DRBall]

Hello as the title says I'm getting ready to change out the1974 260Z distributor to a 280ZX. The 260Z is an automatic. What other changes I need to make in order to ensure the swap works. I still need the coil and to change to a 12-80 vice 12-92 ? ?What else is needed IE add wiring to the neutral start switch etc....I have searched...

[Zed Head]

I would look in the service manual and compare the vacuum and centrifugal timing curves first. The later year 280ZX distributors had some pretty aggressive vacuum advance curves, for emissions and fuel mileage purposes. The wiring diagrams are in the manuals also and will show you the differences between the two types.

[LeonV]

What's the reason for swapping the 260Z unit out?

[DRBall]

LeonV, I'm just getting parts, the car has not been run for years.....The current system might be fine however it's nice to have a back up....The control for the distributor might not be working, these boxes have had problems over the years....Cold solder joints etc...Right now the prior owner said it would not start.....The 260Z had that one off system as far as I know IE very spendy to replace the 280ZX not so much.....I just want to get the work done to this car and enjoy it......I should get the sheet metal I need for XMAS and I get the other stuff sorted out...The 280ZX distributor was only $30.00 or so and it should work...I have heard of others doing this swap.....

[Zed Head]

Note the comment about "details may differ" - http://atlanticz.ca/zclub/techtips/distributor/index.html

If you have the 260Z electronic ignition with VR distributor, you could use the GM HEI module in place of the stock module. Cheaper, and just as effective.

Check the advance mechanism on both distributors. If either doesn't move, take some time to break the rust on the ball bearings loose before forcing it. You might be able to get it moving again without breaking the plastic bearing cage.

[Captain Obvious]

Something else to watch for is that you've got an automatic... That means that you've got the dual pickup distributor and it's accompanying two input switchable curve ignition module. The system switches timing curves depending on engine temperature. Cold engine = advanced, warmed up = retarded. Controlled by the temperature switch located in the thermostat housing (the two wire device next to the single wire device which drives the temp gauge on the dash).

You need to understand that system. Might not have to use it, but you need to know what it does so you can decide for yourself what to do with it.

[DRBall]

Cool thanks for the info, Zed Head and Captain Obvious , like I said I'm gathering parts and the 280ZX had the parts I might need....I wonder though after reading the Datsun 260Z manual has any one made their own test for the iginiton box being the test box is not seen out side a dealership....As for using the GM HEI module that might work as well. Or taking the vacumn advance system and placing it on the 280ZX distributor with the wiring for the switch...One other question is did the 280ZX have a different disributor for the automatic in the first place ?

[Zed Head]

If you know the year of the distributor, you can find the advance curves, and details about automatic versus manual in the Electrical chapter of the FSM. Along with diagrams and drawings of how things work and go together.

I don't think that the ZX vacuum canister will fit on the Z distributor. It's different.

www.xenons30.com/reference

www.xenons130.com/reference

[DRBall]

There are alot of 280ZX timing tables however at rockauto they have a vacumn advance for a automatic that I might buy...From some of the charts of timing tables I've seen the 280ZX N/A automatic motors just had a different advance so I might go that route..Remember this is still a back up plan....With junk yard parts....The spark boxes are still around but a 1000.00 or so hell no at least on blackdragon auto parts.....

[Zed Head]

I think that the factory put a lot more effort in to tuning the timing than the distributor rebuild companies do. If you look, you'll find the same part number for a whole range of years from the rebuilds, but no vacuum advance data. They are either using a generic, probably mild and safe timing advance, vacuum canister, or each canister has a random advance curve. I think the canister is new though, so it's probably just a mild 10-12 degrees total at high vacuum, to avoid any pinging at all.

I can understand the urge for a backup plan. That's how I ended up with the GM HEI module. I installed it just to make sure it would work if my factory module died again, the left it on and kept the factory module as the backup. I'll probably never use it again.

CO made a good point about the dual pickup ignition. If you go away from the factory ignition setup you will lose that. On the manual cars, like my 76, it's main purpose seemed to be to keep the idle speed up while the engine got warm. It might have a different purpose on the 74 auto cars. Should be described in the FSM though. I deleted the second pickup on mine and just live with a low idle for a couple of minutes between the AAR closing and the engine reaching full temperature.