Carb Stud

[73SWBBB]

Anyone ever heard of a broken carb stud making its way into the engine? Is that even possible?

Driving along and had engine runaway which i've never had and just popped it into neutral. the rpms kept climbing so i turned the key off. This was in traffic, i managed to make it to a turning lane. It started back up with a bit of a backfire from the carb, but otherwise seemed to be performing up to par. I drove it down the road another 2 miles and came to a stoplight when it quit running. I started it back up with loads of white/blue smoke. I had to give it tons of gas to get it running and finally i was able to pull into a lot and check it out. The carb stud is gone. Truck seems to run ok now and there is no smoke but there is rattling in the engine so  shut it down. Obviously im going to have to tear this thing down but was wondering if anyone else has ever heard of such an event. This will be my first V-8 tear down and I'm pretty nervous since i still owe money on the dang thing!

[topp]

Yup, it can happen...
Usually the offending piece will make it into a valve....possibly the cylinder....

[big bear]

o man that sucks.  sorry to hear. well, now that i read about this happening im sure my truck is next lol

[Grim 82]

I would shine a light and poke a piece of wire in that bolt hole to see if that is the case. I seem to remember the carb mounting holes on my intake having a dead end, and the last carb studs I installed were a different thread pitch on each end, and the non-threaded portion in the middle was a big enough diameter that they bottomed out against the intake and only go in until you run out of threads.

[1979C20]

Try replacing the stud and see how it runs. The stud could have just fallen off, and you have a bad vacuum leak without it.

[73SWBBB]

Last time i tried to start it- it seemed to run fine but i didn't run it long because i heard metal on metal, so there is definitely a piece of something moving around in there. There could be a vacuum leak but its not going to cause what I'm having. I had enough tools in the truck to get the carb, distributor and intake manifold off before the tow truck came. I found a small piece of the stud about the size of a pencil eraser. It was smashed up pretty good. I have not been able to locate the other pieces yet. I had to get ready for work. So here I sit, contemplating how much this is all going to cost me in the end and hoping I don't go to over the top buying non related items during the tear down. I just like everything nice and new when its put back together but its pricey! Big block parts are ridiculous. I also found out I have Merlin heads. I don't know if thats good or bad.

[73SWBBB]

So the stud is definitely broken off in the carb. Any ideas on how to take care of that? I don't know what size carb it is yet. Its a Holley. My guess is I'm going to have to have someone machine it out of there while its off the truck and hopefully not do any catastrophic damage.

[Blazin]

I had a washer make its way down past a valve and on top of a piston once. Let me tell you what, that made a heck of a racket. Sounded like a bearing knock but up high. I pulled the head, whizzered the top of the piston. Stuck the head back on and it ran fine for years after that.

[73SWBBB]

Yeah right now I'm just hoping once I get those heads off I dont have any damage on the cylinders walls. 

[73SWBBB]

Carb stud went onto the the #7 cylinder and beat the shoot out of the piston top and valves as well. In the process i also found the #7 cylinder wall cracked not once, but twice. So it looks as though this thing might be going up for sale. I just dont think i have the money and resources to get this guy back on the road. Not anytime soon anyway.

[bigchevyc30]

man i hate to hear that