Shorter Logic COPs for MS3X?

As many of you know, I have decided to go MS3X with COP. I originally started out with Toyota COPs from the Prius/Yaris line of engines. They're these bad boys right here:

http://www.rockauto.com/en/moreinfo.php?pk=937247&cc=1443496&jsn=364

Problem is--I wasn't thinking about those engine being OHC engines and the plugs being way down in the valley. My Starlet is a slant four and the plugs are no deeper that the plugs boots which are about 1.5". I'm sure I could fab something up to make the COPs I bought look nice but I'm wondering if there are a shorter length alternative?

Can COP be modified to a shorter length?

Not my engine (mine has twin IDFs--(insert man grunt here)--but you get the idea. The COPs will stick up past the valve cover.

In our Sentra, the connection between coil and plug is just a rubber boot with a spring inside it that is compressed between the bottom of the coil and the top of the plug. It looks like it could easily be cut down to fit an engine with the coil much closer to the plug.

Mine seem to be about four inches from the very top of the input plug to the bottom of the hard plastic--it then becomes a rubber boot for the spark plug. Looking at it, the terminal for the spark plug is indeed a spring but doesn't seem to want to compress any further.

Is there something magical in that four inches of hard plastic or is all of the important stuff up in the logic/main terminal connection for the ECU to COP?

I don't know what's inside the tube other than the springloaded spark plug connection, but I'd suspect all the important stuff is in the epoxy-filled part at the top of the CoP. I don't think you'll find anything a whole lot shorter (since I don't think there are any pushrod engines that came with CoPs!), but maybe look at sportbike units.

In reply to GameboyRMH:

I guess I could chop one up and see...LS coils would work but aren't recommended without a cam trigger. I just have a crank trigger.

In reply to redvalkyrie:

I'd be tempted to mount the coils on the firewall and just build a custom set of wires to connect them to the plugs. Otherwise I'd seriously consider fabbing a bracket to hold them all in place and help support them.

You may be on to some thing there...I could mount the COPs on the fire wall, remove their spark plug boot, and run a lead from the COP to the actual spark plug....

If you were going to do that, what would be the advantage of COP vs. just mounting a traditional coil pack on the firewall, which is A) handy to secure and B) easy to connect a plug wire to?

ProDarwin wrote: If you were going to do that, what would be the advantage of COP vs. just mounting a traditional coil pack on the firewall, which is A) handy to secure and B) easy to connect a plug wire to?

Save a little money on buying more parts perhaps...but that's about it.

ProDarwin wrote: If you were going to do that, what would be the advantage of COP vs. just mounting a traditional coil pack on the firewall, which is A) handy to secure and B) easy to connect a plug wire to?

Wouldn't it be the same advantage as mounting the COPs directly to the spark plugs? The short spark plug cables wouldn't sap any power. LS coils are basically the same thing-- indivual coil packs mounted to the valve covers that run short spark plug wires to actual spark plugs, correct?

That said, my other option would be to create a four hole retaining plate for the COPs that then secure to the firewall. It would look a little goofy with four inches of COP sticking out of the spark plug holes but function before form...

Wouldn't LS coils be the easy button here?

Make a bracket over the engine and use the OE LS wires, or put them on the firewall or inner fender and use custom wires.

Or use the COP units that you were planning to use and fab a sheet metal bracket to hold them securely in place connected directly to the plugs. There is a Nissan industrial engine that I work with a lot that has COPs on a bracket like that.

Also, Suzuki 'busa COPs are pretty small, some other bike coils could be even smaller.

LS coil would be perfect if I wasn't using waste spark based a 36-1 crank trigger wheel. The LS coils, from what I read, need a camshaft position sensor . The cam shaft is quite a pain to get to in my engine as it's OHV and the cam is buried behind the timing chain cover. That, in itself, wouldn be possible to over come. However, removing the timing chain cover requires dropping the oil pan.

Mount the coils to the motor not the firewall, I have run into noise problems with the coil not on the motor.

You can hang them off a bracket from the bosses on the valve cover.

Note* If you do, run a braided ground to the valve cover/coil bracket as that valve cover is not grounded.

Why MS3? You have excess disposable income?

An MS2 will do full sequential with COP on a banger. Or are you adding a MS3x (which is the expansion board for a MS3) to an MS2?

It's cheaper to add a Quad driver board to the MS2 JBPerf.com and moves the high current noise off the mainboard. If using low impedance injectors and logic level coils use this board . It all fits nicely in an MS2 case.

I'm losing the dizzy so that will clear up a lot of room. I have to peace the dizzy to oil pump drive in but the internals and cap will be leaving.

I have the MS3--purchased about one month ago. So, maybe I did have a little extra cash to burn through.

I will now mount the COPs to a bracket that ties into the valve cover. Seems easy enough

AFAIK, many sportbikes use a CDI ignition system. Would using these coils be an issue with Megasquirt? It seems like every MS I've seen controlling spark uses inductive coils.

I'm puzzled by the notion that the coils care where the ECU is getting its timing info... Is it about needing not to fire also at wasted spark timing, lacking cam info? Is it that different for other COP arrangements? Do they take a long time to, uh, is "saturate" the right term?

ae86andkp61 wrote: AFAIK, many sportbikes use a CDI ignition system. Would using these coils be an issue with Megasquirt? It seems like every MS I've seen controlling spark uses inductive coils.

I thought most newer sportbikes (as in, from the age of EFI) used inductive coils. Anyway, all that matters is that the coils can be triggered from a 5v logic signal. It seems that most CDI CoP systems have the coil-on-plugs connected to an "amplifier" box that connects to the ECU, so the interface to the amplifier box is what you'd have to check.

Ransom wrote: I'm puzzled by the notion that the coils care where the ECU is getting its timing info... Is it about needing not to fire also at wasted spark timing, lacking cam info? Is it that different for other COP arrangements? Do they take a long time to, uh, is "saturate" the right term?

The only reason the coils might care where the ECU is getting its timing info is if they take so long to charge/saturate/whatever that they can't fire frequently enough to run an engine to the maximum desired RPM in wasted spark mode, in which case they would require a cam sensor signal.

The only reason the coils might care where the ECU is getting its timing info is if they take so long to charge/saturate/whatever that they can't fire frequently enough to run an engine to the maximum desired RPM in wasted spark mode, in which case they would require a cam sensor signal

From my understanding this isn't the case with MS3X. A cam sensor would get me away from wasted spark but as I said--there's no way to get to the cam.

I did come across these:

https://www.diyautotune.com/product/ign-1a-race-coil/

They're 5V logic control, can be fired directly from the MS3X, and mounted to the valve cover. They're like LS coils but charge in 2.5ms and can be run in wasted spark.

Thoughts?

Run 'em. There are lots of other OEM coils you could look at as well.

What's this about not using LSx CNP's in wasted spark?

• sincerely, concerned I6 running wasted spark w/ LSx truck coils.

I believe the truck LS coils are fine as they have a large heat sink. I've read some strange explanations as to why they won't work and one member here in my other Megasquirt thread commented that he had several LS coils die when run in wasted spark.

One theory is heat and dwell time. The other is more of a Holley EFI issue-- something like the coils feed back into the ECU and fry it.

I think for now I'll stick with the current Toyota logic COPs that I have and tidy them up with a nice bracket to hold them in place. I have them, they're free, and they are known to work. Later on I may experiment with something else but those LS type IGN-1A coils are $70 a pop...it's unlikely they would provide any increase over the Toyota units in performance and reliability. Plus they're a dime a dozen at the junkyard and only $20 new.

When I did MS3 on the SVO I used the distributor as my cam sensor since it had a hall sensor built in. Has anybody just done a contact using the #1 cylinder through the plug terminals before? One side the coil plug on the cap and the other #1? Probably need to throw in some debounce code so it latches in while the contact is sliding across #1 so that it doesn't see multiple triggers. Might need too much voltage to jump that contact to use 5 volts directly, might have to break out your thinking cap.

Jeff