CAS/CKP and tooth resolution
 

• 91 chassis
• 99 head with CAS in rear
• 97 block with 4 tooth hub
• MS3x

1. Can I run the rear CAS in combination with a CKP for my toothed crank hub?
2. If true, can I lead the CKP wire from the CAS to the CKP sensor? Then splice 12v and ground?
3. What is the total resolution ms3x can handle? Is there a recommendation? 32?

Thanks.

1) No unless you have the magnetic-type CAS, in which case you can cut one of the two inner "teeth" to get sequential, and swap the front trigger for a 36-2 or other (the stock 4-tooth trigger is uneven and won't work this way).
2) Yes but you also need to use the 99+ cam sensor if you want to use the stock 4-tooth trigger wheel.
3) The MS3 can easily handle say a 60-2 crank wheel but you also need a single cam pulse from the CAS in this case - see 1).

Thanks Rev,

This is not what I was hoping to hear, but it is understandable. I do not have the option to run the 99+ cam sensor, because my valve cover will not support it (protege valve cover).

If I am understanding you correctly - If I were to get a 36-2 tooth hub wheel, and cut two ears off my Magnetic CAS. I could run a trigger wheel CKP off my existing CAS wiring ?

Does it matter which pair of ears?

If using a 36-2 crank trigger and the NA CAS for a cam sensor, you'd need to modify the CAS so it supplies only one pulse per revolution. This could be done by cutting either the inner 2-tooth ring or the outer 4-tooth ring down to one tooth.

Why nit get 99/00 valve cover? Seems the easier thing to do then try to hodge podge other stuff together.

Would I just run the wiring for both sensors from my existing CAS plug harness?

I thought Cam gears needed to be magnetic as well? Is there a special cam gear type for the 99?

yes you need the 99 cam gears, or any chinese-adjustable that are compatible with any NA/NB (except VVT).

https://www.miataturbo.net/general-m...m-gears-87595/

BTW it's not magnetic, it only has some "nubs" to stimulate the sensor. if you get chinese make sure they have the right height (distance from the sensor) ;)

fwiw- I just drilled, tapped and screwed/threadlocked in a stud on an adjustable cam gear for the NB cam sensor. Ran several seasons of racing like that.

what loss of resolution or accuracy would there be running just NA CAS?