[Steven Pisonero]

I was swapping out a carburater on my 1979 Cadillac(425), I am pretty scatter brained so it did not surprise me when I could not find one of the carb nuts. I just popped another one on there. When I started the car and hit the gas, I heard the horrible sound of metal. It was loud and ugly. The car ran for about 10 seconds with that noise, before I turned it off.

I am a rookie here. I am going to pull the intake manifold. I dont know if that sound can be made if it got stuck in the valve, or does it sound like it definitely made it into the piston chamber?

If the nut made it into the chamber, does that mean the engine is toast?

Is there any way to pull the nut out without pulling off the heads?

thanks everyone!!

[techinspector1]

Originally Posted by Steven Pisonero

Is there any way to pull the nut out without pulling off the heads?

There is, a bore scope and flexible retrieval tool, but it's not practical in your case. You need to see where the damage was done. If the nut found itself between the piston and the head at the edge of the piston, even if the nut didn't smash through the crown, the chances are pretty good that the top ring land has been smashed into the top ring, pinching it and rendering that piston into a non-player at best. Then it's time to pull the pan, pull the piston and rod, replace the piston and reassemble. You won't know what other damage has been done until you get in there, maybe bent valve(s).

Get yourself a gasket set and roll out the toolbox.

[MouseFink]

Try a magnetic retreival tool. If the nut is sitting on top of the valve and has not made it into the combustion chamber, you have a good chance of getting it out. If the nut has made it into the combustion chamber which is not likely unless you have started the engine, the nut will the damage the piston exactly as previously written. The nut will be smashed against the cylinder head, crush the top ring land and seize the top ring in the groove as soon as you start the motor.

Never use stainless steel nuts to hold the carburators on. Stainless steel is non-magnetic. and the magnetic retreval tool will not pick it up. Whatever you do, don't start the motor until you retreive the nut!

If you cannot get the nut out, the intake manifold and cylinder head must come off.

[a1supersport]

I'd suggest you pull all the plugs and see if you can find it in one of the cylinders...just to take the easy route first. If you get lucky you might be able to pull the nut through the s/p hole...when you find out which cylinder it's in. If you get the nut out...intact, you could try starting it again.

Depending on how damaged the nut is, if that nut is intact, but crunched, pretty much guarantees you've got at least some piston damage...which would mean: "start" at your own risk. Won't take long for a smashed piston/stuck-ring to damage the cylinder wall.

[techinspector1]

Originally Posted by MouseFink

Try a magnetic retreival tool. If the nut is sitting on top of the valve and has not made it into the combustion chamber, you have a good chance of getting it out. If the nut has made it into the combustion chamber which is not likely unless you have started the engine, the nut will the damage the piston exactly as previously written.

You may need to re-read the OP's first post.
"When I started the car and hit the gas, I heard the horrible sound of metal. It was loud and ugly. The car ran for about 10 seconds with that noise, before I turned it off."

[pepi]

Not a load of options here, serious damage and no parts fishing will change a thing, best luck would be just a piston replacement, do not even want to think about scoring in the wall ...

I cringe reading this post, but I think a rookie is about to become more experienced and go from rookie too junior in a short short ..

''It's always wise to to know where your nuts are .......''



both types

[MouseFink]

OOOPS!!! I failed to notice that you already started the motor.

Therefore, the engine has already swallowed the nut so itis time to GTO (Get the Tools Out). Pull the intake manifold, the head and inspect the damage. If you are lucky, all you will have to do is replace one piston and the rings on that piston.

My '56 Chevy rce car broke a valve spring and swallowed a valve at 5700 RPM. The only damage done to the motor, besides the valve spring, was the valve was bent into a "S" shape and a little pit in the cylinder wall. The valve guide was even good. Usually that would at least crack a head or cylinder wall. I was lucky as far as engine damage was concerned.

What is bad about it was that I was drag racing a 1960 Edsel at the time and I had him by two car lengths.

[T-bucket23]

If the nut made it into the cylinder, you have problems. You are not the first person to have this happen so dont beat yourself up to bad. I had one that the owner dropped a washer into and it actually got stuck holding the valve open. It made quite a racket as the push rod was just jumping up and down. Once you get the intake off you should be able to see the backs of the valves. Take a peek to see if one is hung open before you go and tear the heads off.
It is not likely but it may save you a couple hours of work. Of course if the valve is hung open to far it may have also hit the piston.

Good luck

[timothale]

My brother even bent a crank when he dropped a valve at 6000 rpm. He had a shop pull the head and they only replaced the valve, A year later I got the car and had trouble with the clutch. when I pulled it down the main bearing thrust surface was gone, it had 1/2 of end play. the piston was cracked. the crank had .030 warp and all the rod bores were stretched, the rod bearing to crank surfaces were good but the back side of the rod bearings was where the wear took place.

[m72spokes]

First off, never admit that you started the motor knowing there was the possibility of the nut being inside. (you will be teased for quite some time)
I think we all have spent hours looking for that dropped part.(murphys law)
My only suggestion is, when you find the nut, make a neckless out of it and hang it on the tool box as a reminder.
Best of Luck.

[rwilliam99]

If it makes you feel any better, when I was putting my motor back together, I did the same thing. Only difference was that I THOUGHT I dropped a nut in the intake. I knew I couldn't leave it there, so I pulled the intake and heads and found NOTHING. So I put it all back together....I knew if there was even a possibility of it being in there, I had to remove it, and if I didn't pull the heads, I wouldn't know for sure.

I've learned a lot of lessons the hard way when it comes to motors.....And I'm sure I have a lot more to learn.

Good luck with what you find. I feel your pain.

[American Muscle]

Originally Posted by m72spokes

First off, never admit that you started the motor knowing there was the possibility of the nut being inside. (you will be teased for quite some time)
I think we all have spent hours looking for that dropped part.(murphys law)
My only suggestion is, when you find the nut, make a neckless out of it and hang it on the tool box as a reminder.
Best of Luck.

That was very helpful............NOT

[Steven Pisonero]

Thanks everyone. The car sat for 6 years before this, I am not sure if it is worth rebuilding. I may upgrade to a 472 or 500, or I may just junk it. THe 79 cadillac is not my favorite body style anyway

[Steven Pisonero]

IF the nut made it into the piston chamber, what is the likihood that there was no damage done? If there is a possibility I could pull the heads, remove the nut and replace the heads, it may be worth keeping.

Thanks again guys!

[ericnova72]

Originally Posted by Steven Pisonero

IF the nut made it into the piston chamber, what is the likihood that there was no damage done? If there is a possibility I could pull the heads, remove the nut and replace the heads, it may be worth keeping.

Thanks again guys!

Just about less than 0% chance of no damage if it made it clear to the piston, you only hope is that it didn't make it past the intake valve.