So by now you all should know that while I pretend pretty alright, I really don't know my way around the vehicles I own. There are some basic items I'm just not sure about, so I thought I would ask them here.
1) how can I tell if my clutch is dying?
I'm not noticing any slipping, but I don't have the best driving style, and this is only the second manual I've owned, so I'm not sure what I should be looking for.
2) what's the best method to go about checking and setting timing?
Specifically on the 1.6 miata. I need to open up the timing belt cover to actually see the gears, I assume? This comes about because someone mentioned having a timing light then asked where my distributor cap is, which I do know my car doesn't have, but I don't know what timing mine is set at from the previous owners description of "it's setup to run high test gas". That could mean it has a different crystal in the ecu which is something I can find no information about other than there is in fact a crystal swap, or the timing has been advanced to that magical 14 degree mark.or it could mean whoever worked on it for the PO hosed him and fed him a line of bullE36 M3.
Sure, Google is full of answers, but a lot of them contradict each other, which is why I turn to you.
Clutch: Put it in like 4th gear, go to a hill and stomp on it. If it slips as some point, generally at the top of the torque curve, your clutch is dead. Dying? Well, in my experience, they either work or they slip.
Set the timing on just about anything: Find the timing marks, put the ECU in "check or set the berkeleying timing" mode, hit it with a timing light. Buy the shop manual and it will explain it all. Note that you only set the timing if there is a distributor. If you have coil on plug or waste spark, there is no timing to set. The ECU does it for you based on the crank position sensor and cam position sensors (if equipped). "Setup to run high test" could mean some kind of ECU flash, if that is even available for Miatas, or total bullE36 M3. ECU's may have a crystal, but that would only set the clock and you don't want to be berkeleying with that.
Clutch test I do at work is, about 20-25mph, put it in 4th or 5th gear, go WOT with the clutch disengaged, then pop it after the revs go up to 3000-4000rpm. It should pull the revs right back down again. If it hangs at that speed, the clutch is capital-B Bad. if it sleazy-slides down, the clutch is marginal. If it drops the engine right down into "why are you at WOT with the revs this low" territory, clutch is fine.
Don't do this test more than once or maaaaybe twice. If the clutch fails the test, doing the test will make things even worse and not tell you anything you don't already know. If the clutch passes, then continual repeating is a good way of overheating the clutch and progressing you to failing the clutch...
Buy a service manual. Even if it's only a Haynes book. That is the first purchase I make when I buy another car, and I've been wrenching on the damn things for 40+ years. A book can be an immense amount of help.
Keep the computer handy as well. Youtube can be your friend. I use it on occasion because it can save time.
Last but not least, ask on here. There are a bunch of smart guys and gals on here. They have worked on just about everything. They know the answers to any generic question and most specific ones. They really don't mind answering. There are quite a few of us that actually enjoy it.
There really isn't any good reason to mess with the timing. Adjusting it on miatas means tweaking a cam sensor on the back of the head on the drivers' side. It's a bit finicky however and over adjusting it is no bueno for the engine or for power. It's best done on a dyno so you can actually see which spot is the best and then lock it in. Mine was at something like 13.5 degrees on Shell 93 octane. 14 degrees killed 6 hp and even more torques so we dialed it back and stopped searching for power that wasn't there.
If your clutch is feeling "funny", remember that it's old. It might be some shakey hydraulics acting weird. If the slave cylinder is more than a few years old it's a cheap and easy thing to replace for ease of use and reliability. Flush everything with fresh fluid and you'll be amazed how much better it feels.
Kyallroad said:
Mine was at something like 13.5 degrees on Shell 93 octane. 14 degrees killed 6 hp and even more torques so we dialed it back and stopped searching for power that wasn't there
That right there is my concern/thought process.
I'm trying to get a baseline on the motor, basically. I've owned the car 2 years, maybe 6k miles, and it just gets strange once in a while. Makes a weird noise, or feels like it's ignoring my inputs. I can't force it to reproduce, and it only ever lasts a couple seconds.
It just kills me that "well my buddy did some stuff to it, so only feed it 93 octane and it'll be happy" is all that I know about its previous work. And that someone who is really good with bondo did a lot of work to the rear wheel arches.
Writing this post I'm starting to think I should probably check my ecu and all my ground connections before I bother with anything else, something might be lose.
It just looks like I won't be using it at all this autocross season, so while it's in inactive status, I want to actually get to know the car. I probably should schedule some dyno time, to at least see what it has.
To get a bit more specific on your timing bit:
On a 1.6, nobody is tuning the ECU, you either have the stock one or a replacement/piggyback. If you have to question whether you have one or not, you don't, you're stock :)
To check the timing, find the diagnostics plug on the driver's side shock tower. While idling, Put a wire between GND and TEN to put it into diagnostic mode. Then you can check/set your base timing.
As was stated a lot of times 14° is too much, you can verify this with a stopwatch and known distance.. I'd set it around 13 and just accept that it's happy. Without internal work, there's no reason to need 93 octane on a 1.6.
The previous owner probably just cranked the timing up, and that's how he got it to stop pinging.
Didn't know ECU,s had a crystal.
I haven't heard about crystals since we made primitive radios as a kid.
Heck, quartz watches have a crystal. So does your computer. So do a whole lot of chips. If you need a reference frequency, it's how you get it. Makes it easy to do things like check engine speed. Can't figure RPM if you don't know how big an M is 
Change out the crystal (aka timing chip) and you can change the rev limit because you've just messed with the value of M.
1.6 Miatas do pick up some power and torque if you run them at 14 degrees timing. Now, a lot of people read the timing marks wrong and end up at 18 degrees when they think they're at 14. But it is a change that's stood the test of time.
1.6 Miatas don't throw check engine lights, but armed with a paperclip you can see if there are any codes stored in the ECU. That's the first thing I'd do with occasional weirdness.
Rev, I think you'd appreciate Mazda Miata Performance Projects. It's got all sorts of well-documented how-tos, such as how to check the timing and how to change a clutch along with lots of good pictures and fewer errors than a Haynes.
