1976 280Z Restoration Project

[wheee!]

21 minutes ago, Captain Obvious said:

Another thought about the mounting of the coil packs... In the original application, the coils are designed to be pressed down all the way "home" against the top of the valve cover and the mounting hole comes into contact with the valve cover itself. Probably with a proud standing boss where the mounting bolt threads into. In addition, there is a sealing surface (might even be a rubber ring?) just below the electronics module portion that is designed to seal the larger hole in the valve cover.

In your design, the holes you have the coil packs poking through is much smaller than the original design and your mounting tabs are hanging in free space. You don't want to stress the mounting tabs by putting a bolt through them and tightening them up while it's unsupported below the pack.

Kinda hard to do without marked-up pics, but here's the issue I'm talking about... See the gap underneath the coil pack where the mounting bolt goes through? That thing is just plastic and you don't want to put a bolt through that and tighten it up. I suggest either using some sort of standoff boss (could be as simple as a tubular spacer) to support the bolt hole, or even better would be to make the holes in the COP bracket larger (like the original application) and have the coils mounting face sit down further (flush) against the plate.

Without some sort of support under the mounting bolts, you are going to cantilever the coil pack body with the bolt and potentially crack the mounting tab off:

 

Yup. I have already considered that. There is indeed a rubber grommet that is causing most of the offset value between the plate and the COP. I can remove the grommet but I like the idea of some vibration insulation there. I will leave it there, and build a standoff for the COPs. I believe there may be some grounding that occurs in that bolt hole as well, so the plate will be grounded to the cylinder head too.

The original design has the COPs in a recessed position in the DOHC cover. The bolt holes then sit flush.

I might consider making a collar of sorts for them too.

[Captain Obvious]

5 minutes ago, wheee! said:

I believe there may be some grounding that occurs in that bolt hole as well, so the plate will be grounded to the cylinder head too.

Yeah, I was wondering about that as well. There are three connection pins on the pack, right? Two of them have to be for the logic level signal (sig and ground), but what is the third wire for? I wasn't sure if that third connection was a ground return for the high voltage side or if that is a diagnostic "misfire" detection input back to the controller.

It would sure make sense if the spark current flowed through the mounting bolt. The smaller the circle for that current, the better. it's really noisy and I wouldn't want that in any harness if I could avoid it.

If the mounting bolt does provide one side of the high voltage coil, you should be able to measure coil secondary resistance by sticking one lead up the coil pack and the other on the metal part of the mounting boss. Without looking anything up, probably along the order of 10K-30K ohms maybe?

[wheee!]

I have the specs at home, but the grounding point through the bolt is a redundant safety as I remember. It does not form part of the firing signal. You cannot test these COPs with a multi-meter,  you need a functioning system.

[wheee!]

Another shot of the COPs

[wheee!]

And from the look of a valve cover designed for these COPs, it seems the entire grommet seats inside the cover, then the bossing rises up to meet the bolt and COP head.

Edited March 4, 2019 by wheee!

[240260280]

I don't think the COP "sticks" offer much value solely due to their shape.  

The key advantage is one unit per plug so less heat, more time to reset after a fire.  The stick is only a design byproduct to reach deep into the engine through the head. This is not needed for the Z as the plugs are readily accessible.

Most COP-like applications I have seen use short spark plug cables.

 

[wheee!]

I partially agree. For me, the main reason is to NOT have wasted spark so I can set individual dwell and fire with the Haltech.
As for the LS type coils, I have heard good and bad reviews. And I didn’t want any spark plug wires. At all. And you lose the factory location for heater hose, it has to be rerouted.

[Zed Head]

Some of the COP coils have their own dwell control, I believe.  I think it makes the head bigger.  There's a bunch of COP options out there.  Some smaller motorcycle COP coils might be less bulky.

Just getting vicarious.

https://www.ebay.com/itm/09-12-KAWASAKI-NINJA-ZX6R-ZX600R-OEM-IGNITION-COILS-COIL-SPARK-PLUG-CAPS/153137994597?epid=18017017407&hash=item23a7bc5b65:g:-6sAAOSwZthbZzSc

[Zed Head]

I don't know if you call this bendy thing a wire, but it's what one guy does.  Blake Machine.

http://www.blakemachine.com/performance_parts_by_blake_machine/datsun_coil_on_plug_brackets_6__4_cylinder

[wheee!]

Yup. Seen it.

That is a dumb coil. It needs an igniter pack. Not interested. Those are ford cops.

[Zed Head]

17 minutes ago, wheee! said:

That is a dumb coil. It needs an igniter pack. 

That was my point in post #2456.  Your Haltech might have its own "igniters".  If it does you don't need an extra one on the coil.  You might be redundancing.

Many ways to get it done.  The manufacturers' reasons for doing things are usually focused on ease of manufacturing and packaging parts.

You could probably cut the ends off of the coils you have and make them smaller.  That long tube probably just has a wire inside with a clip on the end.  It's a solid plug wire.

[Captain Obvious]

2 hours ago, wheee! said:

And from the look of a valve cover designed for these COPs, it seems the entire grommet seats inside the cover, then the bossing rises up to meet the bolt and COP head.

Yup. I've not messed with those specific COPs before, but that's what I figured.

And thinking about the wiring connections a little more... If they're logic level triggered, then the other two connections have to be +12 and ground. So the three connections would be trigger, power, and ground, but not necessarily in that order.  It's still unknown if the high voltage side shares the same ground connection or if it snags a separate ground through the mounting bolt.

I did a little digging looking for a wiring diagram for how those COPs are connected in-situ (same part on Acura's and Hondas) and didn't turn up anything. And I would take that as good news... Seems reliable enough that not a lot of people are asking questions about the wiring diagram?  

Anyway, I'm clearly getting into the academic part of it that doesn't matter to the application. LOL.