1980 280ZX Distributor

[nrossi6969]

I just put a remanufactured 280zx dizzy on my 72 240Z. It seems like everything is fine, but I haven't tightened the adjusting bolt yet because I want to get the timing right. When I turned it over, it sounded like a preignition or pop inside engine, and then today when trying again, it just backfired hella loud. I'm thinking its just not timed right? I was going to take #1 plug out and make sure its TDC but didn't have the tool with me. Any ideas?

[DoctorMuffn]

I have an old spark plug which a friend securely welded a metal extension to. I placed this contraption into the number one spark plug hole then (with all other plugs out) carefully, CAREFULLY brought the crank around with a ratchet on the front pulley bolt (clockwise) bringing the piston up to contact the extension on the old spark plug. I marked the pulley where the pointer was indicating once I made soft, SOFT contact.

Then I turned the crank around the other way (counter clockwise) until I made soft contact again. I believe turning it this way is not an entirely appropriate thing to do, but timing is important and I was careful. When I made soft contact again on my make-shift piston-stop I marked the pulley again where by the pointer. Upon taking into consideration any play in the mechanical timing set I then divided the short distance between my marks made on the pulley in half and determined TDC to lie at that point. Fortunately it matched my timing marks on my crank pulley and pointer on my front cover.

Without a tool, but assuming you had a mechanically well-timed engine before you replaced the dizzy I would just use a flashlight to peer into the spark plug hole of number one to determine TDC. Having the valve cover off to ensure no valves are lifted would indicate TDC between the compression and power strokes.

The intermediate shaft between your oil pump and dizzy is worth checking as well. TDC reflected in that shaft should look like the first picture in post number 21. It's position is roughly 11:25 with the smaller bow shape towards the front (according to my '73 240Z manual). All the rest should follow - the dizzy placement, the cap and rotor placement, the spark plug wires.

You just joined so I'd recommend utilizing the search function to peruse different topics to isolate posts regarding your issue. There is so much information on this site to be gleaned.

Enjoy, and welcome.

[tlorber]

Not sure if you've figured this out yet, but make sure that you are not 180* out of phase. This happened when I first put my zx dizzy in and I had the same symptoms you described.

[DoctorMuffn]

And I think my module(s) is(are) going(dying)...

My E12-80 module which came with the distributor: Generated a rough idle on occasion but would accelerate through and through. However, the rough idle turned into intermittent shut-offs of the engine forcing me to start it again. Then these shut-offs started happening while driving at speed with violent shocks to the drivetrain upon restart. I replaced it with the module sourced from the yard when it was shutting off at idle every other light as well as cutting the engine off while driving at speed for long, dangerous periods.

Replacement E12-80 sourced from yard: Generated a rough idle a couple days after installation. It doesn't cut the engine while idling yet, but it occasionally doesn't rev out freely. It is beginning to feel like my old pertronix in that it cuts sputters while holding steady throttle at cruising speeds.

All problems are intermittent.

Frustrating!

[wa5ngp]

That's what mine did with my zx replacement after a while. I replaced the module and then the bearings all blew up leaving me stranded. So I am starting all over with a remanu like you did.

However, I had a similar experience with the original points dizzy where mechanical wear of the bushings would cause some jumping of timing to the extent that the motor would shut off. I doubt that's your problem if your dizzy was remanu'd properly.

And you are correct the sudden shutoff does provide a sudden mechanical shock not to mention shock the mind if you are crossing a busy intersection.

If I have similar problems with my newly rebuilt dizzy I will try a honda module or hei from GM. I have collected a few of these from the junkyard. I wonder if the problem is that there is not enough heatsink compound between the module and where it mounts so it may be overheating?

This doesn't seem right. My original beater 81 ZX went over 250K miles until the dizzy bushings wore out. Never had that module problem.

Edited December 4, 2010 by wa5ngp

[DoctorMuffn]

I considered that possible heat sinking issue, but you give good reasoning why it shouldn't be. What occurred to me though was a total electrical system issue starting with the alternator and it's external regulator.

I'm still using my old 240 alt and reg and I was postulating that if the voltage spiked considerably more from that alternator than it would from a 280ZX alternator that could cause issues. Alas, I don't have a scope to really assess these things for sure... Were you running an externally regulated alternator with your swap?

And boy does that ever shock one's psyche when the cutout leaves them stranded while crossing oncoming traffic or slowing out of nowhere with rapid unaware traffic rushing up from behind... SCARY! It's not how a car should run.

And my remmanned from Autozone felt pretty solid. I pulled it partially apart when I got it to check the vacuum advance (which was fine) and ultimately re-centered the inductor because it was contacting the pick-up ever so slightly. It's a process... Let me know what you think about the above, Don.

[SteveJ]

Scopes are relatively cheap if you have a laptop computer to use with them. I picked up one for less than $200.

[wa5ngp]

Being an old EE nerd I (of course) have an old storage scope that goes to 2 ghz. After I get things running again I'll take a look. I want to do this anyway since I plan to modify the tach so its reliable yet doesn't reduce the spark.

I really do think that its the heat. Even if firmly mounted on the dizzy that area gets pretty hot and heat is the biggest killer of electronics in everyday use. So once mine is running I'll probably move the module onto a heat sink and mount it on the fender well next to the coil.

I still have the 240 alternator but I am going to replace it with the one from my 81zx parts rust bucket.

BTW, I was in the middle lane of IH35 going about 70 when that dizzy bushing gave out. I quickly got over to the right side and got off the road. Not a pleasant situation trying to figure out what's wrong while 18 wheelers come blazing by. The huge whoosh and my cap flies off and I'm 70 miles from home. The odd thing was that it would start up and cough and die like fuel starvation. I was all set to blame the alcohol in the fuel.

Don

[DoctorMuffn]

That's intense, Don!

Let me know what you find out when you hook up the scope.

[DoctorMuffn]

I pulled apart my oldest E12-80 ignition module and took some pictures. I have no idea what any of it does; but for those who may know and may be interested this is what the inside of a $150 dollar module looks like. At least that's what I paid for the Wells replacement from Autozone.

E12-80 ignition module internals