Sometime in the next 72 hours an NB Miata is getting dropped off. Initial analysis is that the timing belt slipped. Something something something, glowing exhaust manifold, something something, not running any more. The hope is that a new belt and re-timing it will yeld a perfectly functional Miata and then it can go home.
Any advice on this particular course of action or likelihood that my life will work out the easy way for once? I've never done anything on a Miata more complex than a tech inspection at rallycross. How hard can it be?
done a few of them.
rad out and just take things apart. drop the swaybar.
If its a VVT motor DO NOT dissassemble that valve covery part wrong. parts fly EVERYWHERE and its a pain to find them all and reassemble. (did it once, added 3 hours to the job)
Crank nose. CLEAN THE SNOT OUT OF IT AND USE LOCTITE. the keyway is a critical part. everyone knows about the small nose NA's, but I know 3 big noses that have lost motors to that keyway. If things are worn in the slots, consider putting on hold until new key, boss hub, etc can be acquired.
timing marks will get you there, but go ahead and turn the motor over a few times by hand to be sure its right, taking all the covers back off for a one tooth off mistake sucks.
Most of the guys over on Miata forum boards make out like a timing belt job is rocket surgery. It's not at all.
I used a Gates kit from Rockauto that included the belt and idler and tensioner for 40 odd dollars.
The Flyin Miata tool kit for the job is very nice to have, particularly if you're changing all the seals too. The kit has two seal installers that make the job Cadillac. I'd be happy to lend you mine if you decide you need it.
I had a glowing catalytic converter in my ls400 once from a loose distributor cap. Check the simple things once you've got the car on hand.
I have all the flyin miata timing belt tools if you need them seth.
EvanB
UltimaDork
12/17/17 4:19 p.m.
It should feel like a simple oil change after rebuilding an AMG engine.
Dusterbd13 said:
I have all the flyin miata timing belt tools if you need them seth.
I'll be sending you a message after I talk to the owner. Thanks for this.
And thank to everyone else. Any recommendations on a service manual? I've become a fan of proper torque specs and good diagrams.
dculberson said:
I had a glowing catalytic converter in my ls400 once from a loose distributor cap. Check the simple things once you've got the car on hand.
Will do. The car spent some time with a mechanic and it's coming to me with "jumped timing" as the diagnosis. I'll poke around and probably ask some questions here before I tear into it. Turns out that available schedules mean that it'll be here in a couple hours. I do love new projects.
I've been replacing timing belts for decades and I know I've done at least one on a NB Miata but I remember absolutely nothing specific about doing it. That tells me that either my memory is even worse than I think it is or, that as timing belts go the Miata one is no big deal.
mrhappy
HalfDork
12/17/17 7:14 p.m.
IF the water pump needs replacing, now would be the time to do it since the water pump is behind the timing belt.
codrus
UltraDork
12/17/17 8:33 p.m.
To confirm the "jumped timing" diagnosis, spin the motor to TDC and take off the top timing cover. It should look like this (minus the adjustable cam gear on the intake and the FM cam gear tool). Notches on each gear pointing at the marks with the corresponding letter:
There should also be 19 teeth between the notches at the top:
Vigo
UltimaDork
12/17/17 9:44 p.m.
I know I've done at least one on a NB Miata but I remember absolutely nothing specific about doing it. That tells me that either my memory is even worse than I think it is or, that as timing belts go the Miata one is no big deal.
I don't think i've ever related to anything more in my life. It is all blurring together now and rather than endless details i just have a casual confidence... that doesn't always transfer to the people asking me questions. 
Sometimes it seems way harder to make people believe I can do something than to actually do it.
I guess one tidbit i would offer is if you are doing the shaft seals to be very careful not to nick the sealing surface of the shaft in the process of removing the old seals.
