Bad news over here. 383 seized on me out on the street tonight.

Yes, I was getting up on it a little bit. Not that much though. Testing out the new 4.30 gearset.

Symptoms:

- Seemed like it 'let loose' with a BIG cloud of smoke, couldn't tell nature of it. Probably water?
- Engine died, and wouldn't turn over thereafter.
- Coolant is gone, probably went out tailpipe.
- Plug #6 was 'broken' entirely off at the insulator when I went to pull it out. Thermal shock from a coolant rush?
- Oil is a milky brown. Water I guess.
- Can turn engine at crank counterclockwise, but not normal rotation.
- Water was on the #4 plug, not sure of others yet.

So what's the story? Blown head gasket? It had been running a little rough lately, maybe it was already on the way out.

I'll pull the rest of the plugs tomorrow. Hopefully, it's just hydraulically locked? I sure hope I didn't drop a valve or something. That would suck...

 

Head gasket leaking into the #4...for sure...was ALL the coolant gone?

I would surmise head gasket and possible hydrolock if the leak was bad enough...

Sorry to hear about it though...that sucks and *** help me if this newest incarnation of my 406 were to do that, I would probably cry(one of the only acceptable reasons)...and then not touch the car for a year...

 

since plug 6 is broken, you must have some internal damage. a valve dropping or a broken piston is quite possible, though you can have a look by simply removing the valve covers. I imagine you had a huge cloud of white smoke out the tailpipes.

Sorry for the misfortune, what rpms were you at?

 

that really sucks, hope it is a cheap fix

 

Craig,

Ouch. Can you rotate the engine backward at least two full revolutions? Once you get all the plugs out, try turning it forward again.

I've got a bad feeling that this isn't going to be a quick fix....

 

Yeah...

Got the remainder of the #6 plug out, it was crushed at the electrode. Bad things in there I think, well beyond hydrolock. Will see tonight when the rest of the plugs are pulled and the valve covers opened up. Then pull the heads & see what the damage is. I'm guessing a valve dropped out and chewed it's way to block-compromising Nirvana. Bottom end is/was forged, valvetrain was good, keepers all new. Maybe broken stem or spring? Weird.

 

Well, found the problem.

Valve spring broke on #6 exhaust. Had probably been broken or about to give for a while, since the car had been a little rough idling for the last couple days.

Problem is, without that outer spring to hold it closed, the valve floated and got snapped. Then, it made its way from the #6 combustion chamber, through the #6 intake valve and port, and up into the manifold.

Then, it made its way down into #1 intake, where it got lodged at the valve seat.

Guess your intake port work CAN be too open!

Ah well, next we'll get the heads off and see how bad the pistons are & if the 010 block made it. Good thing is the valvetrain stuff looks good (solid roller). Good thing...

 

If the coolant got into the oil, it could have washed out your bearings also...be sure to check your under your pan...

 

Yep, I'm willing to bet the pistons are going to have to come out, so I'll just redo the bearings then. It's only .030 over, so I've got some room if I need to rebore due to block damage on the walls.

I think the coolant didn't have too much time to work it over on the oil side. Since the exhaust valve got wrecked into the head (I hope), it probably just let it blow out that direction under ca. 10# steam pressure. There was a fair amount of water in the intake area. i guess once that exhaust valve punched through the #6 intake, it just steamed back through. What fun!