Jsmply

I'm in the same boat, I've had two dealers now go for a ride with me and neither can hear anything out of the ordinary. I definitely hear it and I cannot believe I didn't notice this before (first started noticing this about 3,000 miles ago), but I'm not saying its impossible, perhaps I just didn't notice and now that I have my ears listen for it.

Either way, I was more interested in you answereing my other question. If this noise was caused by something bad (forgive my ignorance here) like a piston kissing something or a messed up valve or whatever else could be making the noise, would the car run perfectly normal for several thousand miles (in my case, at least 3,000)? I know some things have been know to not cause trouble till way down the line, but I thought those were symptom free scenarios. I would assume that once you started hearing a noise from something bad, it would only be a matter of time before that noise caused a noticeable failure in driveability. Again, be gentle with my ignorance, lol. As I've said before, thanks for being an asset to us all with your responses.

xviper

I'm generalizing when I say that noises from something "bad" usually only get worse. Sometimes they get worse if they become noisier and sometimes they get worse when the noise that was there before, disappears.
Valve noise is a paricularly difficult one to catagorize. In the old days of push rods, it was considered better to have a slightly ticky valvetrain because you then knew that the valves were not being pushed overly far down into the cylinder. If you could hear no valve noise, you were risking high rev valve or rocker damage.
If you revved it really high (and not just an over-rev as most people might think) in a sustained manner (several seconds) for some goofy reason (like bouncing off the rev limiter repeatedly and often), this can stress the valvetrain. In particular, with this car, the valve retainers have seen examples of cracking.
Your engine can run normally for a long time and when cracks and fractures develop far enough, things go sour.
A typical example of damage occuring which does not manifest itself for sometimes thousands of miles is a torn or cracked CV boot.

Jsmply

So anotherwords time is no indication? I'm not really sure where to go from here then. I've tried two dealers and a few local owners and they seem to think the engine sounds fine. Its hard to trust that though when you are talking about an expensive drivetrain. I baby the car and change the oil usually before 3,000 miles and have already done the tranny oil with less than 8,000 miles on the car. Doing the diff soon as well. Its frustrating though when you can't get a good diagnosis on the vechile.

Thanks for your input. Maybe I'll switch over to synthetic this oil change and maybe even consider a valve adjustment. It would be interesting to see if that makes any change. Maybe I should just try to go test drive a few s2000's tomorrow to see what they all sound like for comparission.

xviper

A change to synthetic may not resolve anything. Modern day non-synthetics can be just as good as synthetics.
If you are going to get a valve adjustment, that might be the perfect time to closely examine the retainers. This may shed some light into your situation.
Here's what to look for:

https://www.s2ki.com/forums/index.php?act=S...=0#entry6064501

Jsmply

Thanks for the post Xviper, could that be causing this sound? I'm a bit confused. If the noise was from a cracked retainer, would that make a sound? I was under the impresesion that if the retained let go it would drop the valve. At which point the engine would fail or would it make noise for a while before doing so?

Again, the car is taken pretty good care of and I've never over-reved or anything like that, but still the noise drove me nuts for a while. I've finally started to accept it as normal after all the posts I have seen from other members with similiar noises (especially the echo'ing off another object part b/c I don't really hear mine unless its being echo'd) but it can't hurt to be overly cautious.

xviper

I can't say with any kind of certainty. Anyting is possible. I think Billman explained once that a cracked retainer can allow the spring to rise come in contact with the cam lobe. This can cause a noise and score the lobe. You'll have to ask him for details on this. He's the expert in this area.

Given that you take care of the car and have never over-revved, I think you should relax. Get someone to listen to it with a mechanic's stethoscope. Abnormal valve noise will be very apparent and uneven. I think you are worrying about nothing.

Jsmply

Well I can say that my noise is definitely not uneven. It is a fast ticking noise that can be easily heard and is in constant rhytm. It sounds like someone doing morse code extremely fast. Faster than you could probably ever do by hand. Again its really tough to hear while just driving out in the open street, but if I pass another car or have an object for it to echo from (a wall, high curb, etc) I can hear it everytime without fail. Its definitely consistant for what that is worth.

I think I'm going to see if I can pay a local member to walk me through a valve adjustment just for the fun of it. I'm assuming that plus an inspection while we have it open should yield be benefitial, can't hurt, lol.

Thanks

Race Miata

Since injector duty cycle is very short with throttle off (even at 3000-4500rpm), I'd imagine that unlike valvetrain noise, injector noise level and/or tone would change between gassing and throttle off even at the same rpm range. Note that I have no experience with injectors noisy enough to this point so I'm just guessing here.

xviper

What I mean by even is when you listen with the stethoscope over each valve and rocker (16 of them), they should all sound the same. You place the point of the scope over each valve. You'll know you've got the right place as the sound is maximized once you are directly over each one. A bad valve will have a different sound that the others. Without a stethoscope, you can't pinpoint which valve is doing it. If they are all the same, you are most likely hearing normal valvetrain noise.

xviper

I think you are very clued in to what happens and you have reminded me of a principle of injector function that I had forgotten. Indeed, the ticking in Former's car goes away during throttle off at the rpm when the sound is most evident. This might lend more credence to it being the injectors (well injector in this case).

PS. You may be a fricken genius.