flywheel separating from crank?

[HOLLYWOODSPIDER]

Hi, all. I'm currently trapped in Victorville, CA with a strange problem. I was driving from Las Vegas to Los Angeles late last night. Everything was working as it should I was tired, so I pulled off the freeway to take a nap. When I awoke and attempted to start the car, but the starter wasn't turning the engine, just spinning.
No problem, just push start it, right? No. It won't turn over with pushing.

Strange thing: if I put it in gear and tuen the starter, the car moves. That means that the starter is engaged and attached to the clutch. Does that mean that my flywheel has broken or become unbolted from the crank?

[pope]

I see what you mean, but if that were true, if you took the plastic observation piece off the lower portion of the bell housing, some fly wheel bolts would fall out, unless you had removed it before.
My guess is its in the engine.
Did you break a belt on the engine? Maybe you are just spinning the crank.

[bwilson27]

I think you're right. It sounds like the flywheel is not connected to the crank somehow.
Good luck, I hope it's an easy fix.

[HOLLYWOODSPIDER]

Timing belt is intact. Since push starting yielses no engine movement, it's definitely not connected. Question is: broken or bolts fell out? Is it possible for bolts to vibrate free? Everything else on my car seems to vibrate off. Also, if it were broken flywheel, i'd expect some sort of cataclysmic noise. There was no weird sounds. Worked fine, then didn't. I'm going to buy a cherry picker and pull the engine. Friend with AAA plus is rescuing me and getting car towed home.

[HOLLYWOODSPIDER]

Sorry for horrible spelling and grammar. Typing on phone with very little sleep.
So cold and wet here compared to home. Can't wait to get home.

[pope]

I have done this many times myself. It is much easier to get the front wheels on ramps then work under the car, on removing the trans than removing the entire engine. I can remove the trans solo. You just need a couple of long entensions and a swivel socket for the four trans bolts.

Good luck.

I guess what happen in Vegas doesnt always stay in Vegas!

[HOLLYWOODSPIDER]

I hate when the last hour of a trip takes 9 hours. Just got home with the car. Going to sleep. Will update on progress when it happens.

Pope- how to remove trans? Remove donut first?

All help, comments and commiseration are greatly appreciated.

[pope]

Dont touch the donut! Remove the four bolts that secure the drive shaft to the rear axle and lower. Remove the drive shaft supports in the front. The drive shaft will pull out of the yoke on the trans with the donut intact.
You might have to unscrew the rear trans support a little to lower its rear end a little to slip the drive shaft supports off their bolts on the floor underside.

Get some sleep.

[ITA124]

Hi from Australia,

This sounds very unusual. If the flywheel had separated, you'll now, we've had cases where they have separated at full revs. Very messy. Further to this, the started would not engage, and definitely not with enough strength to move the car. So I think your flywheel is intact, on the end of the crank shaft anyway.

When you say the starter was spinning when in neutral, is this free spinning, or slow spinning, ie something in the engine is turning, but not visible from the outside. If this is the case, remove the spark plugs and see if the pistons are moving up and down. Start at #4 and forward to #1. If there all moving, then your crank hasn't broken. This is unlikely anyway.

Move to the front of the engine, and more specifically the crank pulley. Is it there? the 38mm nut may have come off along with the pulley and the cam sprocket. If it's there, then check that it is engaged to the crank. There is a keyway that the pulley's engage into for the drive, if the keyway shears then the engine will rotate without the cams turning. If this is the case, then your pistons may have hit the valves by now. The next question is why. I would check the free rotation of your cams, should your alternator/waterpump system seize, the belt will slip. The cam belt is positively engaged.

That's all I can come up with on your explanation. Good Luck

[So Cal Mark]

the flywheel bolts can't come out with the clutch bolted to the flywheel; they can loosen but end up hitting the clutch disc hub before they can come out. And it makes quite a noise when that happens. This scenario sounds very strange

[HOLLYWOODSPIDER]

The starter is turning the edge of the flywheel, evidenced by the fact that I can move the car with it. The starter is indeed powwerful enough to move the car. I did it all the time on my first fiat to move it when it didn't run (I was 15 with no experience).

The cams are not moving. Have not yet investigated the pulley situation, but the timing belt is taut and intact and only a year old.
It would make my day if it was something that can be remedied w/o removing the engine or trans.
The strangest part is that there was no noise or crunch or anything. Car was driving fine at 80mph, then wouldn't even try to start 40 minutes later.

The starter spins at what appears to be a normal rate, but without the rhythmic slowing that the compression provides. Spins like regular if u remove the plugs. The starter is the new gear reduction style.

[mdrburchette]

Is the bendix engaging the flywheel teeth?

[ITA124]

I've started a few fiats in my time on the starter motor, this comes about when the clutch cable snaps in traffic.

The starter spins at what appears to be a normal rate, but without the rhythmic slowing that the compression provides. Spins like regular if u remove the plugs. The starter is the new gear reduction style.

The fact that your starter is spinning at a normal rate, like with the plugs removed, suggests that there is no connection between the pistons and valves. If this is the case, there is no compression stoke as the gasses are leaking past partially open valves.

When you crank the engine over, is there air blowing up through the carby? (or into plenum on FI cars)

I'm hinging by bet on either a sheared crankshaft key or the guts of the toothed timing pulley is chewed out. As for removing the engine, you may want to check the valves.

Keen to find out

[HOLLYWOODSPIDER]

Well, I am sure hoping it's the shear key.

Tomorrow I will pull the plugs and use a dowel to see if the pistons are moving.

The car is a '78 model, so the valves are non-interference. If the shear key is the problem, my valves should (in theory) be untouched. I sure hope so, because the head was just redone a year ago.

Could a shear key just give out? I've got 136,600 miles on the engine. it had been behaving like a new car until I pulled over and turned it off.

[HOLLYWOODSPIDER]

Guts of timing pulley being ripped out is one I hadn't considered but now think is most likely scenario.
If the pulley guts were missing, the timing belt tensioner would maintain belt tension. I will see if the alt belt is moving.

Once again, I really appreciate everyone's input.