What the back of the 1.6 head is supposed to look like.
 

http://img29.picoodle.com/img/img29/...dm_e9a21c1.jpg


No CAS, no coilpack. Thank you, Megasquirt.

Sexy. Can we please see the first two COPS, too?

^And a full view of the heat-shield.

what did you plug the cas hole with?

Detail on the heatshield is posted in this thread: https://www.miataturbo.net/forum/showthread.php?t=17242

I'm afraid I didn't document the build process of the COP setup. The bracket is a piece of 1/4" thick aluminum stock. I cut the COP holes with a 1" holesaw, and countersunk the three holes on the back (where it bolts to the valve cover) so that the raised posts on the VC extend up into it, allowing the bracket to sit flush on the cover. The COPs mount to countersunk bolts run up from the bottom of the bracket. Two nuts are jammed on the bolt between the COP and the bracket to set the height at which the COP stands.

The bracket:

http://img26.picoodle.com/img/img26/...tm_57fadea.jpg


To interface to the factory wiring, I hacked apart the igniter, wired into its pins, and filled it with eopxy:

http://img27.picoodle.com/img/img27/...rm_5f28b4e.jpg


Two 4,700 uf capacitors are wired in parallel inside a little plastic box which I zip-tired to the main engine harness. The COP harness passes through this box:

http://img26.picoodle.com/img/img26/...sm_01da926.jpg



The CAS hole is filled with the plug that all the NBs came with to fill this hole. I got mine from a local dude who installed an NA CAS on his NB.

cool i never knew that

Two Caps?

two 4,700uF caps almost equals one 10,000uF cap.

More info on removing the cas please.
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That's really clean looking Joe. I still want to try Mikeflys technique of grinding off the two teeth on the crank wheel and using the stock NB sensors instead of the CAS. Glad I save my block off plate pieces to replace the CAS with.


He installed a 36-1 trigger wheel on his crank. Unless you want to have an adapter machined you're not going to be able to replicate it.

Keep your CAS if it works, his didn't so he upgraded.

ahh, I see. Thanks CJ
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Joe, you've gotta be one of the most respected guys on this forum, and for good reason.

Instructions for removing CAS:

1- Unscrew CAS lock bolt.

2- Firmly grasp CAS and pull it out.

Simple enough? :)

Seriously, here's the writeup on what I did: https://www.miataturbo.net/forum/showthread.php?t=20241

CJ is correct in that my primary motivation for doing this was that I'd been having all kinds of trouble reliably triggering off my stock (and apparently faulty) CAS. I went through several circuits, some of which worked better than others, but none were perfect. So I decided a 36-1 wheel would be an interesting project to undertake.

When I first heard about mikeflys1's 4-1 attempt I was impressed. I didn't think it was possible owing to the timing constraints, but I figured I was wrong.

The reason it didn't work is that MS1 requires all teeth (except the missing tooth) to be evenly spaced. The teeth on the stock wheel are oddly spaced, and MS will tend to interpret the longer spaces as missing teeth.

I question whether even machining off two teeth will work for NB owners, since the crank sensor gives a very odd single-double output and I question whether MS1 can be made to interpret it. You might need to grind down the cam as well. I do have an idea however.

I don't know if it's mechanically possible, but if you can realign the crank sensor closer to the wheel it should work. Basically, move the sensor in so that it's almost touching the wheel itself. Cut off all four teeth. In their place, cut three gaps into the wheel: one at -60°, one at +30°, and one at +120°. The space you don't cut at +210° will be the logical missing tooth. In this configuration, the system should run as a 4-1. Set Trig A = 1, Trig B = 3, and no returns. Leave cranking at time-based. You may have to invert the sensor output.


And as for the capacitors, it's very simple. I had several 4,700uf capacitors lying around, but no 10,000uf caps.

http://www.yanivalfasy.com/SM/profilepics/Cartman.jpg

The 2-toothed crank wheel definitely works....for sure this time :) I've put like 150 miles on it over the weekend including a couple trips to redline without so much as a hiccup.

I'm going to give you a couple more weeks then join you in using the stock sensors.

You know what, you're absolutely right! I originally missed the part where you noted that you were using the NB cam sensor with your new 2 tooth setup. I guess it makes sense- the MS1 doesn't mind getting two cam pulses before a crank pulse, since the cam pulses act only as counter resets and are not timed.

Genius!

glad it worked for ya' joe!
Im leaving to Tennessee for a while, you Abe and I should get together for drinks before I leave. :bigtu:

Are you not concerned about overheating the coils running them in wasted mode like that constantly? Coulda/shoulda kept the CAS for the No 1 TDC signal and made it proper COP instead. As a bonus you would draw half as much juice powering them :-)

Joe i am very curius what you are gonna do come smog time? RR oe parts or what?

Enough people have been doing it for enough time that I'm not really concerned. I'm not exactly breaking new ground here with this setup, I remember seeing one of Emilio's friends doing it three years ago. Besides, the CAS needed to die. It was a moral imperative.

I'm moving to North Carolina in six weeks. The Smog Polizei can go fist sheep for all I care.