athens944

My '83 944 just cut off on me going down a hill around 45 mph. I pulled the plugs and noticed the second plug (Bosch 4) had a bent end. Any idea what may have caused this? Thanks.
I must mention I foolishly left the oil cap off, could something have gotten sucked in there?

TomH

Sounds like something is loose in there, but not likely due to the oil cap. More possibly a broken valve or valve spring. Does the car run with a new plug? You might want better advice before trying to start motor again.

athens944

Engine does not turn at all. I tried it by hand. There seems to be some definite interference somewhere. The valve spring theory sounds quite plausible. I'll dig deeper. thanks.

Peckster

Too wierd. If there was a broken valve head inside, it would have made a lot of noise before the engine stopped running, although it could account for the engine not turning over. Have you tried turning the engine in reverse?


From the sounds of it, it could be bigger than a dropped valve head.

athens944

I just took the camshaft off. The #2 intake valve broke in half. The timing belt did not break. I'm going to pull the cylinder head and see what happened to the piston. I guess at this point it would be wise to redo all the valves.

athens944

When I drained the oil, it was new antifreeze first and then the oil came out. Is this due to the valve situation or am I looking at another problem?

Peckster

Must be a hole in the block somewhere. The oil floats on top of the antifreeze, so it comes out second. It wasn't mixed because it happened after the motor stopped. Sorry.

Bob S. 1984 Silver

Sounds like you might have had hydraulic lock. Fluid in the combustion chamber. It's non compressable so something has to go. The best clue is the engine would not turn. Look for a crack or a blown gasket somewhere.

Good luck..keep us posted

Bob S.

athens944

The valve end got wedged into the cylinder head sideways. It also ruined the #2 piston. Not sure if it is worth fixing at this point. I haven't noticed a crack in the block yet. I'll keep digging. thanks for the response.

Peckster

You don't mess around, do you. Does the hole in the head go through to a water passage? That would be good news, at this point.

athens944

Found something that is very disappointing. The wall around the second piston is cracked. I guess at this point I'd be better off just putting another engine in. I am still curious as to what would have caused this. Any ideas?

Peckster

Could have been a broken valve spring, caused by fatigue, or over-revving the engine.

Bob S. 1984 Silver

Athens;

That "crack in the wall" is the result of hydraulic lock. At this point it's not important, the block is toast and cannot be fixed.

Good luck finding a great replacement

Bob S.

P.S.Man, I would love to know the sequence of "What let go first"

Konstantin

1 hydraulic lifter
2 valve bent
3 piston broke valve
4 block is damaged
5 get a new engine

Konstantin

Peckster

Maybe, here's my take.

1. Valve breaks when impacted by piston due to over revving or broken spring.

2. Valve head lodges in head creating hole through to coolant passage in head.

3. Coolant released into cylinder creates hydraulic lock next upstroke.

4. Cylinder cracks.

5. Find new engine.