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79 280zx ignition timing


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While replacing several needed maintenance items, ie; new injectors, fuel press. regulator, a few wiring issues, etc.,  I managed to damage the magnet assembly in the distributor.  Apparently the magnets are NLA so I located another distributor and now I'm having a timing issue.  I've removed and replaced more than one distributor and usually know what I'm doing.  After installing my new found zx distributor, I can only get a few degrees of advance when the distributor is rotated full clockwise.  When rotated all the way, the IC unit comes in contact with the first sensor in the thermostat housing. (either the thermatime switch or temp. sensor whichever, i forget).  Is it possible that I have a 280zx distributor from another year that will not work with my 79?  This one is in there with # 1 at the top of compression stroke, 0 mark aligned with mark on damper, rotor dead on with #1 mark on one cap and #1 wire.  Engine starts and runs. But like a lazy pig with the few degrees of timing I can get.  Any ideas??

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8 hours ago, Mayolives said:

 This one is in there with # 1 at the top of compression stroke, 0 mark aligned with mark on damper, rotor dead on with #1 mark on one cap and #1 wire.  

 

Kind of sounds like you have your plug wires off by one terminal.  Turn the distributor to where you have more adjustment room and move the #1 wire to the terminal the rotor is closest to then.

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On 7/14/2020 at 11:05 PM, NewZed said:

 

Kind of sounds like you have your plug wires off by one terminal.  Turn the distributor to where you have more adjustment room and move the #1 wire to the terminal the rotor is closest to then.

 Although my #1 plug wire was at the correct #1 mark on the cap, I tried rotating my wiring one move clockwise with poor result and then rotating them counter clockwise with the same bad result.  When trying to start the engine with both moves it was "way" out of time.  Could a bad IC unit cause my problem?  I haven't compared differences in base plates from on year to another yet but as I remember they are all the same. 

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I was going to ask if you have or had an E12-80 module, and maybe your new one is different.  There's a -92 and -93 and they have an internal timing advance feature, controlled by a temperature switch.  Compare your black box numbers.  There is a trick to using the -92 and/or -93, apparently.  But, just swapping to your old module might do the trick since it's only your magnet that was bad.

 

Edit - forgot to say, you could also swap the magnet from your new distributor in to your old one.  The Z distributors have another adjustment screw underneath that can affect timing.  Maybe the ZX distributors do too, and your two have been adjusted differently.  That's an option also.  It allows you to turn the body of the distributor on the upright supporting portion.

Edited by NewZed
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The IC ignition unit is an E12-80 on both my original and newer distributors.   I will swap the old one back in to see if that works.  The fixing plates do have a bottom screw that will provide more adjustment, but I've tried that with no help.  I'm reluctant to attempt swapping magnets for fear of breaking another 40 plus year brittle old part, while removing the stator on top.  I'm certain that's how the original one was broken.  The stator screws were frozen in place and I had to tap on my driver to get them moving.  If all the above doesn't work out, I have a 78 280 distributor and the GM HEI conversion deal that I'll install.  Thank you for your help.

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Put the two distributors side by side and see if you can see the difference.  The stator ring , the ring with the spikes, might have an internal adjustment that would affect timing.

 

Also, and you probably should have done this sooner, make sure that the advance mechanism on your new one is not stuck.  The vacuum advance moves the breaker plate and the little ball bearings get rusted up.  The mechanical advance has springs and weights but also gets gummed up.  Be careful with the breaker plate if you try to turn it and it's stuck you can break the bearing cage.

 

Might just be that your new on is stuck in the advanced position.  That seems more likely.  Either way you want the advance mechanisms to move smoothly.

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New Zed,  I took your advice by removing the distributor again to see if it was different from the original one. The base and fixing plate are the same.  Although the vacuum controller has a different shape compared the old one it operated just fine when I checked it with my vacuum pump.  The new distributor is very clean and has a Nissan Factory Remanufactured sticker on it.  I'm now concerned that I may have a distributor from another year 280zx that won't work with my 79.  I thought that I had a list of distributor numbers that were used in the different years but can't locate it.  FSM doesn't appear to show numbers either.  I have them for most all years.  The original one was a D6K8-02 8903.  The one I'm trying to use is a D6K 80-03 A8918 and I'm not sure what year car it came from.  Do you know where I can find a distributor part number listing or information on what year 280zx distributors are interchangeable?  I still have the options of trying to swap magnets from old to new without breaking them or converting to a 280Z unit using the HEI deal...... Now for the really "stupid me" story.  Before I removed the distributor to compare things, I attempted to try rotating the wires on the cap one position.  It started with a "jerky" move that out of time engines do, then coughed back through the intake so I shut it off.  Shortly thereafter I was standing in a puddle of oil.  After a little investigation, I discovered my newly blown out rear main seal.  My little job just got a lot bigger.  Not to mention I just installed a new clutch and pressure plate recently that is now probably oil soaked and trashed.  Bummer!   Thanks again for your help.      

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The triggering mechanisms are the same on the ZX distributors. The different distributors have different timing curves but work the same at idle speed.  When a spike passes a spike a voltage pulse is generated.  By "compare" I meant to set them side by side and see if the breaker plates and other moving parts are in the same orientation.  Sit and stare at them for a while.  Set them up so that they should be in exactly the same position and see if the spikes are oriented the same way.  You can use your engine for that also, install them both, one at a time and take a picture of the reluctor spikes and trigger ring spikes.  They'll probably be different.  Then find a way to make the new one look like the old one.

 

The oil in your engine should be below the level of the rear seal.  No reason to create a puddle if the seal blew.  But, no reason for the seal to blow from an engine "cough" through the intake manifold unless it was barely seated.  So that is odd.  Your clutch should be fine, it's on the other side of the flywheel.  Thousands of leaky seals out there.

 

At least you have something to do that doesn't require getting out and about and exposed.  Good luck.

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  • 3 months later...

My timing issues continue.  My original distributor had a broken magnet assembly and frozen breaker plate assembly but I found replacements in excellent condition. I completely dismantled the original distributor, cleaned and lubed it per FSM.   Reassembled it with a new pick up coil, a new vacuum controller, cap and rotor.  Put it back in the car but still could not get timing to advance beyond about 2 degrees.  I've tried three different E12-80 IC units but they did't help.  Then decided to go the "280Z HEI conversion route".  I used a D6F5-03 distributor that has same timing curve as the original except it has a few more total advance degrees listed.  Cleaned it up, installed new pick up, cap and rotor then put it in the car along with new HEI unit mounted properly on inside fender with nut-zerts and added additional grounding points.  Engine starts but I still can't get but a few degrees timing and runs like a pig.  I would think that moving wires in cap would correct this but when I try to rotate wires in either direction on the cap, it's way out of time.  I've been playing with old z car for decades but I'm really stumped.  Do I have a bad ECU?  I'm not sure what else could effect the timing like this.  I put # 1 piston on top of the comp. stroke with the timing mark on zero degrees and the # one wire on the cap aligned with the rotor that points where I have always found it to be on many Z's I have timed.   I sure need some advice before I find a bridge to jump from. (Not so)     

Edited by Mayolives
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Did you swap the pedestal also when you installed the 280Z distributor?  The Z and ZX use a different pedestal and they're oriented differently.

 

Take the adjustment screw completely out so that you can rotate the distributor as far as you need.  See if that gets your timing right, then see if you can move your plug wires to get there.

 

It might be that somebody adjusted the old distributor to work with an oil pump drive gear that was off a tooth.  Now that you have stock distributors it's not "right" anymore.  Set the timing mark on zero on the compression stroke and see if the half moon is in the right spot in the distributor hole.  Here's some pictures, the first one is not quite right but shows the size difference more clearly.

https://www.atlanticz.ca/zclub/techtips/distributor/index.html

image.png.f9cca6fe9c51cce194df6390b89a0a77.png

image.png.efa5008510e72a2322bf97461e4f828b.png

image.png.00dbce624d28a7a3146a612cf8babe08.png

 

 

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Thank you NewZed.  Again an old Z dog learns new tricks!  Your post with pictures pertaining to the differences in distributor pedestals was an eye opener for me.  After again really looking at several sets of

distributor parts left over from my two dizzy rebuilds (280zx & 280Z)  I discovered the differences in both pedistals and fixing plates that allow for adjustment.  After pairing a set properly and reinstalling my distributor for the umteenth time, all is well.  I have all the adjustment I need and have the car timed just right.  I even remembered a short video I saw some time ago at the california datsun site pointing out what pedestal and fixing plate works with the different distributors.   

 

SORRY for the two vids below. I wanted to just post a link and don't know how to remove the two vids below. 

 

 

Edited by Mayolives
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