I currently have a '94 300ZX that is a bundle of fun. I am thinking of taking it to this year's final driving event at Road America in October. The car currently has 184,XXX miles. I have a reciept for a full timing belt service at a Nissan dealer at 134,XXX miles. The interval is 60k, meaning I should have 10k left before it's "due." My intention was to replace the timing gear in the winter months after the final RA event since the car will be parked anyway.
Am I playing with fire, or should I quit worrying and drive?
They usually crap out when you stop or start it, from the shock load of accelerating the cam to/from a stop. Failure at revs is usually a bearing in a idler, tensioner or water pump locking up. On a 60k interval if they used good parts when it was changed last, I wouldn't worry about it.
Unless its been more than 5 years or so, then I'd change it.
I'd go for it.
I'm about to swap in a long nose crank 1.6 into the track rat Miata (it was cheap) and I'm not going to bother changing anything except possibly the RMS.
Then again the Miata engine is non-interference.
If you're within the interval, go for it. They're pretty conservative.
I am embarrassed to say I took my Miata to 90k miles before changing the original belt...it was 22 years old!
Of course, a non interference design.
if it's non-interference, i'd run it.
if it's interference, i'd run it.
It is very much an interference design. 24 valves to interfere across two barely-accessible heads...and the belt was done about seven years ago...
I think the plan will be to run it and see what happens. If it survives...great! If not...maybe time for a TT or RB25 swap 
I'd run it.
Just be sure to shut down if you hear a "kicking up gravel" noise from the engine bay.
That depends on the vehicle, and on a Nissan, I'd run it. As Keith said, they're pretty conservative on their intervals. Now on a 944 or a Subaru, no freakin' way. (Actually, I did track my 944 on an over due timing belt, and I drove it 2.5 hours to the track and back, but I would HIGHLY suggest against that. I'm an idiot that like to press his luck.)
