Well as I posted earlier I was recently having problems getting my car to hold an idle after installing a holley carb. So after breaking my 7th cylinder spark plug a couple times I pulled the head to find out a 9/16ths bolt had somehow sneaked past an intake valve into the combustion chamber!

1. How is this possible? I thought the valves didn't open that far.
2. Well the engine turns over fine and the piston, besides being beaten up badly doesn't appear to be cracked.. So my question is.. if I installed a couple new valves for that cylinder and put it all together, would it run for a while? At least until I have more money for a 350 swap? It would be something incredible if it did.

 

That is....... absolutely amazing. Small enough to fit in the intake, not big enough to fit out the exhaust and somehow it never got pinched in the quench area to instantly destroy the motor (rocks the piston violently to one side, breaks the piston skirt and cracks the cylinder bore vertically almost it's entire length.

If you hadn't posted pictures I would have called you a liar. Is the bolt actually embedded in the head at this point, I assume? I doubt the head will be OK WITHOUT the bolt stuck in it at this point.

Will it run for a while if you remove the bolt and screw everything back together? Absolutely. If that didn't kill the motor nothing will!

Seriously, you know the right thing to do here. You just don't want to do it. Given it's a 305 I can't say I blame you.

 

OMG I thought I had seen it all.

 

I know, I wasn't even mad. Just impressed... Time to throw it back together again and see what she's really made of!!

 

Now that there is Chevy tough.

 

Amazing!! Simply amazing!!!!!!!!

 

Nice one! Any idea where it came from?

 

Thank you for posting those pictures!

 

I had something close to this happen to a friends motor. It sucked a big self taping screw in the intake somehow and it stuck in the top of the piston on its side!!

 

You must've dropped it in down the intake during the carb install. In your other thread, you mentioned the intake valve also had free play up and down. It's clearly off the seat, or bent, in these pics. Any idea what's caused that yet? Eg broken spring, retainer etc.

 

No idea what caused it to have so much slack, but yes it is bent just like you see it in the pictures. I think im going to try running it with a set of used heads in good condition. I have a set of 350 swirl ports, would these work at all for a 305 application?

 

Haha also glad that everyone finds this funny, at least now that lowly 305 has a good story to go with it!

 

We're just guys, sharing a love of damage and broken things (so long as it's the other guy's misfortune )

The 350 heads will bolt on, but you'll take a compression = performance hit, I believe there may be valve to bore clearance issues too,

 

Chevy, like a rock!

 

Remove the bolt from the head and see if it cracked the head or pounded up into the water jacket. If not.....

Buy a new intake valve (it's 1.84" in that head) install it and your rocker arm issue will go away. It's bent crooked where it comes out of the guide so it won't go all the way back up. That also means the valve tip is lower than it should be for the rocker to contact it in the valve-closed postion. So your rocker is loose.

It never made it out the exhaust so that one didn't suffer a similar fate.

It's not gonna be perfect, but for what you're doing perfect is obviously not the goal. All you need is functional.

 

+ 1
onlt thing else i would do is file the top of the piston flat to knock off any loose burs are anything sticking up that could cause a hotspot and detonation. stick it back together with anew valve and spring and see if she runs.
if she runs drive it till it does fail, if not go get a 200$ junkyard motor

 

305 heads are so cheap... why not just find some 081's in a junkyard somewhere? I'd also consider deburring the piston because it's probably a detonation nightmare, but dont let any of that get past the rings. You may be able to machine polish the top of the piston enough to smooth out any serious burr's. It wont look great, but at least it will be functional.

I did that to a 2 stroke dirtbike cylinder head once. Had a piece of basically bearing come apart on the crank and get sucked into the combustion chamber and hammered around for a while at probably 8000 RPMs. Tore it down and the head looked awful, but I just polished it out so all the sharp spots were gone and it ran fine afterwards.

 

I would file or deburr NOTHING. You'll end up with a mess of aluminum shavings and dust all over everything- getting down into the top ringland. I mean, seriously- look at that thing! Don't touch NOTHING you don't absolutely have to. Detonation is the least of your worries.

And, FYI- those don't look like -081 heads. They also don't look like -416 heads. Spark plug boss is all wrong in the chamber. What casting number are they?

 

I still dont get it. I cant imagine that bolt getting there through the intake valve. Geometrically impossible. That was left there the last time the heads were pulled....had to be. That could have happened long before you bought the car.

The top of the piston is beat to heck too. That bolt rolled around in there for a while before it was finally jammed, upright, into the head.

I'd die grind off the head of the bolt off and leave the rest in there and drive it til it finally fails. Or just replace the head...they are cheap.

Im guessing it sounded like a rattle trap before it finally got stuck. Just my thoughts

 

this could probably never happen again like it did for you.. my uncle had something similar to this happen but it was on his old ford ranger that he traded for a real truck (chevy). yea id throw it back together and drive the hell out of it...

 

Bet money there are threads under that bolt. No way that passed through the valve like that. I mean anythings possible but just doesnt make sense....
Maybe you found a bubba fix someone did.

Friggin amazing though it even fired on that cyl lol.

Not into grinding on an assembledmotor either but gota do what you gotta do. Put some KY or shaving cream bet the piston and the wall then do your thing it will catch the shavins, shop vac out. Not like its a new motor anyway.

 

The engine could have stopped with the valve in the down position, allowing it to just roll out. Besides the obvious fact that it IS there, its very possible it went through the intake valve.

Easy way to fix it, is to replace the valves, take it to the machine shop and have the heads machined, replace that piston and rings. Correct way is to completely rebuild the motor.

 

I believe you have the rare BIH (spare bolt in head) coded third gen. A very rare option. The factory put it there in case somebody took the head off and found themselves one bolt short.