1983 Camaro Z28 5.0 carb.
So I made the massive mistake of over tightening my valve cover bolts. I have scoured the internet and forums looking for a problem like mine and have yet to stumble across it yet as well as a good advice on how to move forward.
Anything that could go wrong did in fact, go wrong!! I overtightened a valve cover bolt and the head of the bolt broke off with the broken stud still in the cylinder head. I tried to drill the bolt out but I had two drill bits snapped inside the bolt, I tried to extract it using an extractor bit and this also broke off in the bolt. I should have just left it but I continued. I tried to drill around the broken bits to get everything out to just retap it but had very little luck. I ended up using a small left handed drill bit right above the bolt and ended up drilling too far and apparently went through the head and had coolant rushing out of the head.
I am at a loss right now. I recently purchased the car and the engine (so I'm told) has around 200k on it. I really don't want to replace the head/heads on an engine that probably won't last much longer. I was hoping for a temporary or cheap(ish) way to patch it.

I was thinking about filling the hole with high temp gasket sealer and use the gasket maker to seal the valve cover.
I also thought about adding sealer to the bottom of the hole placing a metal screw/bolt on top of the sealer wrapped in Teflon tape and add more sealer to the top of the bolt, smooth out the cylinder head and seal the valve cover after that.
I am also fairly new into mechanics and obviously just learning as I go. Any suggestions would be very helpful and any additional problems to be aware of in advance would be nice since I've failed to follow instructions so far lol.

 

Just put a 350 in it. You are way beyond fixing that mess now. Chalk it up to a learning experience.

Sealants and such will not hold - cooling system pressure is too high. Fixing that is going to require pulling the head. Unfortunately you have gone way too far with a drill and it's just hammered. Would probably be cheaper and easier to change the head but on a 305 it's not worth the effort. Just swap that engine for a 350. That's some of the worst amatuer broken bolt carnage I've seen - you need some training from someone with experience. That was absolutely salvageable before the beaver went at it with a dull apprentice. Sheesh. Next time seek professional help and ask to be a silent observer.

GD

 

I agree with the General , it's new engine time .

Why ? , , Because at 200 thousand miles that engine is simply not worth spending the amount of money on required to replace the head . Money that will be better spent on a fresh engine . Were this a 60 thousand mile engine maybe , but at 200 thousand miles you've put the final nail in it's coffin by drilling into the coolant passage like that .

I won't kick you in the ***** over it , just remember next time to come to a forum like this first and ask your questions at the first sign of trouble rather than continuing to make a bad mechanical situation worse . My guess is that the valve covers were leaking oil and you thought tightening the bolts super tight was gonna stop the leak ? The thing is , unless the bolts were something like finger tight and truly needed tightening , no amount of tightening right up to and including tight enough to break would have stopped the oil leaking since well before the bolts break the tin valve cover has already become distorted enough to ensure the leak continues unabated .

PS , Welcome to the forum

 

 

It's a long shot but if you could tap the hole that is drilled and install one of these set screw with thread sealant.
If you used a long enough set screw,you could use it to hold down the valve cover as well.


Again this is just a suggestion.I just used a general pic too.

 

That would not help the coolant issue. There are things you could try but I would not be willing to suggest anything knowing the trouble that could happen afterwards if sealant or other product let go. You should replace the head or drop in a 350 or other 305 your choice.

 

 

He's already got a broken easy out , along with two broken drill bits stuck in there now . Those three items along with the hole drilled through to the cooling passage , coupled with the miles on the engine are the basis for suggesting this as the launching point of an engine upgrade .

 

THE WHOLE HEAD IS FULL OF METAL SHAVINGS!! IT WILL NEVER LAST!!! Just sell the car to the yard and just use UBER or Lift from now on.
That was downright stupid. I'll bust your *****.

Good luck and have a super day.

 

Do I see a broken off chunk of a drill bit amidst the metal shavings in/on/around this rocker , to the left of the hold down nut ? Yep , it's doomed ....

 

 

Did you put anything down to prevent the spread of metal chips while drilling?

Don't start the car use a magnet to carefully remove all shavings and pull the head hopefully nothing made it into the oil passages

 

Well we have all made mistakes while learning. At least he wrecked a 305. Not a big loss really.

I understand how this happens with no experience. You get anxious and you "try something"..... let this be a lesson. When it goes south like this - step back and just give it some time. Ask questions. Write down a list of your options if you have to. Watch some videos. Easy outs are BANNED in my shop. They never work except in situations where a left hand drill bit will work better. They nearly always break off and now you have hardened tool steel to deal with not just a soft bolt. It makes the problem 10000x worse. At this point the only hope is to change that head. Could I or someone else with VAST experience pull off some other type of repair? Sure I probably could. But it's not in your wheel house friend. Just pull that boat anchor and start with a crate 350.

GD

 

 

Well, at this point, it sucks, but it's not the end of the world here. Like most have said, when something goes wrong like a bolt head breaks off, you have to stand back and think about it and seek some help before you go and try to remove it especially if you don't know what you are doing. A little advise...Never use bolts on perimeter-bolt valve covers. Use ARP stainless steel studs with nuts for small block chevy application. You hand thread the studs in until you can't spin them with your hand anymore and leave them. Then, thread the nuts on. Valve covers don't have to be that tight. With new gaskets, I tighten mine by hand with a nut driver, just snug, no ratchets. After about 100 miles if I see a seep, I tighten them just a bit more and that's it. Usually, my initial tighten is perfect, but since all gaskets are made in China now, results may vary. If they leak after that at any point, the valve covers are warped or the gaskets are junk.

There are few ways this can be fixed, but it won't be cheap. See if you can find a machinist who makes house calls, we have a couple here, but be prepared to pay more vs. bringing the head to their shop. Some things can be fixed while it's still on the car. They may tell you yes, it can be fixed right there or they may tell you to pull the head. If the engine runs good and doesn't smoke, knock or feel like it has no power, then it's worth fixing as is now. However, if it's tired and worn out then it's not really worth fixing. If it is worth fixing, get a telescoping magnet and go over the entire head and rockers and run it through any oil ports/passages to retrieve the metal that you've put in there. If you don't have one, get an oil pan drain plug with a magnetic tip on it to catch any fragments that might have made it through. I've had 7 lifter clips go through one my engines without damaging it, so you might get lucky!

If you have to pull the head, then you need to research and find some help on how to remove your carb, distributor, intake, etc... There's all kinds of threads on here and elsewhere, such as youtube videos etc... You are looking at a lot of work to replace or repair that head if you have to pull it. It's not that bad though and once you do it one time, you'll get the hang of it. You'll need all new gaskets etc... At any rate, repairing or replacing this head will be cheaper than a crate 350 engine replacement. I don't know what your budget is or if this is your daily driver and you need to get it back on the road or whatever. However, replacing the engine invites all kinds of other work especially if you've never done that before. The 350 will come with no accessories which means not only do you have to pull your engine, but you have to remove everything off of yours and bolt it on the 350. Some crates don't come with intakes or water pumps either. If you want more to go with it, it's more money. You'll be disconnecting everything, transmission, wiring, hoses, seized steel lines, rusty exhaust with bolts that you'll mostly likely have to cut out. You'll need to support the transmission while the engine is out as well and keep it supported. You'll need an engine puller, engine stand or two and some help! You'll need someone to help you get the new engine running too, timing, etc... If you have a shop do it all for you, it will cost you a ton of money. Cost of engine and labor, you're looking at probably somewhere around $5-6,000.00 depending on the shop.

Repairing or replacing the head will keep you around $500.00 or less if you find a good used head already assembled and do the work yourself or have a machine shop repair the head on or off the car.

In spite of all the comments you might get, we're here to help, but you have to ask questions and do some research! Good luck with it!

 

Just swap out the heads. Eeezy peeeezy piece o cheeeeezy.

 

Not so easy. Many more bolts to be undone - how many will break in the process?

 

 

Sounds like a good excuse to go for 45 more cubes.

 

Agreed , at least a couple of exhaust manifold bolts are likely to break on an engine 200K miles old .

Yes indeed , putting anything over $50 into a 200K mile old engine is akin to opening the nearest window and throwing money to the wind .....

 

Given the demonstration of skill showing in his attempt at valve cover replacement and the age/mileage involved I would say this is highly likely. Stripped heads, stripped threads, broken bolts..... oh yeah it would likely be a complete disaster. On the other hand you either learn to swin up against that current or you decide this is not the hobby for you. This is the make or break moment right here. Do you own it and learn all the tricks, buy all the tools, etc... or do you throw the tools down in disgust and make it someone else's problem? It's ok if you want to do that. This is not the hobby for everyone. Many here have been through that. Some of us ended up turning it into a career. Others just do it for fun.

GD

 

Exactly the point I was trying to make. Thanks for elaborating GD.