Is my engine blown ?! Need help!

[NismoFunZ]

Hello!

For some hours ago I tried to start my 300ZX NA 90. The car is in a garage for the winter, and has not been started since late october..

The flywheel in my Z has almost no tooths left.. When the starter is trying to spin the flywheel around, it makes this grinding noise.. but after turning the key couple of times, the engine starts up and works perfectly fine.. Until now..

I turned the key 20-25 times to start my z32, all i hear is grinding between starter and flywheel..After many attempts, the starter got contact with the flywheel, I thought the car started, and suddenly all i hear is a big boom..!

A small amount of white/grey smoke is under the hood when i popped it, and it smells burned clutch..

What on earth is going on ? Was it to much fuel in the cylinders ? Fuel in exhaust system?

I thought the engine was blown, so I took a 27mm pipe and turned the engine 2 times around.. no problem turning it.. So what is wrong ?

Can someone please help me before im buying a new rebuild-kit or engine ? (Allready bought a Specialty Z flywheel and rear main seal;)

[t.mcginley.jr]

How do you know the flywheel has almost no teeth left? If that's the case, you definitely need a new flywheel or the car will never start since there's not enough for the starter to grab. The starter could also be fried from trying to start it so many times.

The boom could have been backfire or misfire, did it sound like it came out of the tailpipe?

[NismoFunZ]

I have allready ordered a Specialty Z flywheel, rear main seal, etc. from COZ.. Just waiting for the package to arrive at my door..

I took off the transmission in july to replace clutch, and then i saw the flywheel needed to be replaced.. And there was a small amount of oil in the trannyhouse, so the rear main seal needs to be replaces as well..

It has to be the gas that detonated, i think.. Just hope it didnt detonated in the cylinder.. I guess that will damage the engine ?

To be honest, i have never heard a engine misfire or gas detonate in the exhaustsystem.. but it was a large boom excactly at the same time when the starter grabbed a tooth on the flywheel. no mechanical sound.

I have not tried to start the car after this, in risk of damage the engine further.