94 CAS replacement

[imperfekt]

Hello, I can't get my Miata to start. Cranks like a boss, cams are turning, no spark.

Code 3! few seconds later, code 2! - wait... there IS no code 2, LoL...

K, so code 3... SGT signal, the white wire on my CAS plug connector, ok ok... as far as I can tell, the wire is not broken, the connection is good...

bad CAS? IDK, but I'm okay with getting a used one or even spring for a new one if I was positive that this was the solution...

Anyways, replacing the CAS - it's on the back pressed up against the firewall, please tell me I won't have to pull the engine :S

[— kung fu jesus —]

I usually pull the valve cover and the bearing that holds the CAS in. Soooo much easier.

[imperfekt]

I usually pull the valve cover and the bearing that holds the CAS in. Soooo much easier.

lifesaver. yes, I will try this asap

few days of work between me and my weekend though (i have wed/thurs off...peculiar lol)

[— kung fu jesus —]

Just check the torque specs on the bolts for the bearing cap. Some people don't remove this a try to line up the dogs on the CAS by feel. If you look at it, it can only go in one way, so I always thought it was worth the extra time to remove the VC and bearing than fiddle with the CAS to get it to line up. I have seen someone use a mirror to line up the dogs correctly and pop it right in, but it is what it is.

Mark the cas position with a sharpie or scribe it with something sharp before removing it. That way when you reinstall it, you don't have to pull out the timing gun to get that right.

[— kung fu jesus —]

Quick write up, from pics found on the internet, you *don't* have to remove it this way, but I find it easier:


Mark the CAS and bearing cap, marker or scratch/score it. This helps you get the timing back to the current setting. Skipping this step will require you to use a timing light to set the timing to where you want it.
cas pic 1.jpg


Quick picture of the CAS. The "dogs" or "ears" can only go back in the cam a certain way. It's a tight fit between the back of the head and the firewall, so it makes reinstallation a bit fiddly.
cas pic 2.jpg



Here is the Oring. IIRC, you can buy one from any auto parts store "box o' O rings" for like $1. I believe it is #222. I have to confirm this.
cas pic 3.jpg


With this method, I remove the valve cover. I remove the two bearing cap bolts and lift the CAS out. Look at the bearing cap and corresponding surface on the head. Sometimes I have found varnish or old oring smegma on there. clean it, but don't sand it. Replace O ring, lube it with a bit of oil pooled in the head, line up the dog on the cam, bolt the bearing cap down, line up scribe/timing mark from step one, secure CAS with the 12mm hold-down bolt, install valve cover,
cas pic 4.jpg

[— kung fu jesus —]

If you have never removed a valve cover, when you reinstall it, be GENTLE with the 11 or 12 10mm bolts that hold it down. Thy will snap if you tighten them too hard. The idea is to squish the gasket, not crush it, so start in the center and work outward in a clockwise fashion. Two to three times around. Grip the ratchet at the head. There are that many bolts for a reason, so snug them down, the gasket will keep the oil in. If the gasket is hard, replace it. It's ~$20 at any parts store and most places stock them. A little dab of RTV in the corners of the "humps" helps seal it.

Good luck! There are more write ups on the web if you need/want more info of illustration to this job. It's not hard to do.

[— kung fu jesus —]

Ugh. I forgot... If you are REPLACING the CAS, you will need a timing light anyways. Scoring/marking the old one isn't going to help much when you put the new one in. It might help you get it close, but you should verify it with the gun.

[imperfekt]

cas seems to be ok... stuck my hand behind the engine and felt around some and whaddya know? she started... the next day, no start. no spark. hunting down an intermittent starting issue isn't my forte sooo.....

[— kung fu jesus —]

Probably a loose/bad connection.

I pride myself on being a decent mechanic, but the tow always keeps my ego and reality in check.

I can't always fix everything, nor do I always have the time.

[imperfekt]

I'm not much of a mechanic, but given enough time and the car's Haynes repair manual, one can probably figure almost anything out... I'm just anxious to drive her around asap

I can't always fix everything, nor do I always have the time.