90 model cylinder head issues.

[solaire]

I'm mainly looking for more information or links to nissan's bulletin for the 90 model cylinder head problems. It is listed as a possible cantidate for hesitations and bogging and I'd like to know what to look for since my car is a early model 90.

[NolimitZ32]

I don't know where you can find it but you need a list of vins or rather range of vins that was affected by the issue, the issue was incorrect machining of the heads, what exactly the problem was that it cause i can't remember. sorry i cant be of more help but what you seek is the vin range.

[t.mcginley.jr]

What you're referring to is the "soft valves" issue. Not sure its so much of a head problem as it is a valve problem.

Here's a few links to check out, but if you just Search "soft valves" on twinturbo.net you will get your answers:

http://www.twinturbo.net/nissan/300zx/f ... my-TT.html

http://www.twinturbo.net/nissan/300zx/f ... alves.html

[solaire]

Wow I could check valves with a borescope if I have to. What I read was something about the CAS mounting area gets wallowed out and allows it to jump changing ignition timing.

[t.mcginley.jr]

Wow I've never heard of that before, that's definitely a new one. How would that go about happening? The CAS doesn't really move except for the part the sticks into the exhaust cam

[solaire]

Thats what I was thinking