The story of how I won the exhaust manifold.
99% of Saturn Vue owners with a 2.2 liter engine experience cracking of the exhaust manifold. Usually everything happens like this: first the rightmost stud breaks, then the next one after it, and then the collector itself bursts in the middle. This is usually accompanied by a farting sound and the car jerking. There is an opinion that all this starts when the catalyst is clogged.
I didn't notice the crack right away. I didn’t have much sound, but the smell of exhaust came into the cabin when parked with the engine running. Dips also appeared when starting from a standstill.
Upon closer inspection, I saw a crack in the exhaust manifold. And also broken pins.
Then it was decided to brew it on our own. I read the literature. I drilled holes, cut the seam with a grinder, took electrodes for cast iron, cooked for half a day, and when it cooled down the seam tore. I couldn’t weld it myself, I thought of sealing it with a patch and asbestos cord, I cut the seam again with a grinder, laid asbestos, cut the thread, applied the patch, it turned out even worse than it was (a farting sound, smoke, and large jerking of the engine.
It was decided to take it to specialists, I looked for these for a long time, read reviews, found them, they brewed them in 15 minutes, without any drilling or ovens, their device is the size of a small refrigerator.
The plane led. The middle was bent from the motor by 2 mm. It had to be milled.
After spending 3 days and knocking down thresholds, I still couldn’t find any specialists in our city. Some are impotent. Give everyone a straight and small manifold, they say we can’t clamp yours...
It was decided to cut it myself.
I bought large sheets of sandpaper 300 and 800, glued it to the tabletop, fastened the top of the collector to the drawers with an elastic band so that it would fit evenly without distortion to the sandpaper, and started sanding with water in 8 motions.
It didn’t come out perfectly, of course, there was half a millimeter or less left, I was tired, I decided it would do.
Between the two middle legs on the platforms, the thermal gap disappeared after welding. I cut it through with a grinder again.
Now we need to make pins otherwise it will tear again. I bought a new gasket, plasticine, a large syringe, soda and chemically pure nitric acid (it contains the highest % of acid). See photo. I made grooves from pieces of bottles and plasticine, diluted acid with water 1 to 1 and poured this mixture into the grooves (without diluting with water, the steel is oxidized and covered with a film, as a result of which it stops etching). I changed the mixture about once every 3 hours except at night. Considering the temperature outside was about 12-15 degrees, I poisoned 2 studs at the same time for 4 days.
Take care of your hands, I accidentally burned mine a little. Also, do all procedures outside as acid fumes are very harmful.
After pickling, we treat everything with a soda solution to neutralize the acid. The studs are suitable for many cars, including Russian ones. To install the manifold, I used wide washers and brass nuts instead of the original steel ones, and lubricated all the threads with copper grease before doing this.
It was tightened as if in a spiral. Starting from the outer studs to the center. That is, cylinder 4 then 1 then 3 then 2, in several passes. Do not strip brass nuts; they are softer than steel.
Good luck to all!
IMPORTANT!: I never etched the pin, due to “suddenly” circumstances that came to light.
In this post, I decided to share my experience: why you might fail if you take on this business and how to make your life easier if the stars are favorable to you.
Since it’s late, and today I fucked terribly with this stud, I’ll try to keep it short and to the point.
Background: I have a Suzuki SV650. Not running - no chain, many components are in varying degrees of disassembly. The motorcycle has an L-shaped two-cylinder engine (V-shaped with a cylinder camber of 90 degrees).
Due to the fact that I had an awl in a soft place and could not sit quietly, I decided to unscrew the bolts securing the exhaust pipe in order to remove it. Why I won’t describe this post is not about this. Three bolts with mats came out, and one soured tightly... RIGHT TIGHT. I poured everything on it and tried to persuade it, but with the next jerk it broke off. There was a small piece left sticking out.
First: if you have such a problem, do not rush to drill.
If space allows, try welding a nut and unscrewing it, it helps a lot of people, I haven’t tried it, because I don’t have a welding machine, my friends don’t, no one in the area knows how to weld, and even in garages, only people who like to stand and look at the car with serious view.
Second: if your welding machine is a machine for boiling eggs, then try to take a thin drill, very thin, and drill 2-3 holes in a row in the stud next to each other so that you can drive a slotted screwdriver into them (or better yet, a head with such a screwdriver) and still try to unscrew it. I learned this method too late, when there was already one big hole in my hairpin, and it could have all ended so quickly and easily.
You can continue the list of methods such as extractors and similar devilry, but I won’t, since all this is only suitable for a simply broken bolt in pure metal or wood.
And I have a tightly stuck M8 bolt in the front cylinder - in a terribly inconvenient place.
This is where the juice begins, as they say.
Attention! Hero of the story. The one that is lower.
He's frontal. 
At first, fishing rods were thrown here, on the forum, I mean. I received a lot of advice from the guys, but they all almost boiled down to removing the head and transporting it to the nearest turner or repair plant or turning plant... I still didn’t understand where I should look for them and, most importantly, how I could get the local turner to help me with something, He’s not standing in front of the gate with a sign saying I’ll waste the engine. Since for me, in general, removing the head is too much... since I am simply not a mechanic, I don’t know the internals, there is nothing to jack the engine with and there are many other reasons “against”, I decided to use the last available anemic method - etching the bolt with acid, nitric acid HNO3 if my memory is bad changes.
We climb onto the Internet where we read that nitric acid dissolves most metals with the exception of gold, stainless steel, platinum group metals, a couple of other metals that are rarely found in the hands of the average person and, most importantly, aluminum from the alloy of which the engine is made.
That is, if you fill an iron bolt in an aluminum can with nitric acid, the bolt will be consumed, but the can will remain intact.
For all this bacchanalia I needed:
Nitric acid. I live in Moscow, where everything you can buy is concentrated, and what you can’t just need to look a little longer. Here I found it in a chemical store. If you are not from Moscow or St. Petersburg, you need to look for it either in the same stores or at chemical plants.
Since this reagent is very harmful, I needed thick thick rubber gloves, mask, which was replaced with a respirator for painting work (better than nothing) and protective glasses, they are necessary, but the acid did not get on them, but a couple of times when manipulating the reagents there were splashes.
Plasticine, he doesn’t care about acid, he used it to mold a funnel over a hairpin. Soda- an aqueous solution of soda serves as an acid neutralizer, but their reaction is very violent, which caused the splashes described above. A couple of syringes. A couple of containers (cans and bottles). The water is ordinary. Aluminum foil - to protect surrounding areas and parts of the motorcycle.
So, everything is there. A few words about the already mentioned acid. The main thing to remember is safety. A broken bolt is nothing compared to chemical burns of the skin and mucous membranes. Even diluted acid is toxic; even without reacting, it floats and releases caustic volatile substances. When interacting with dissolved metals, the reaction is very violent with the release of heat. During the neutralization reaction with soda, nitric oxide 2 is released, which is very toxic + intense bubbling occurs, and if such a reaction occurs in the bottle, a “fountain” is possible. Do not work in enclosed spaces.
Let's continue about the frivolous. With the effort of the fingers this miracle was accomplished. 
Funnel for acid. At the end there is a pin drilled out with a 6th drill.
After reading information on the Internet, I learned that acid in the initial concentration sold in stores of ~67% can enter into an act of love with aluminum, but diluted to 30% (as well as pure 90%) passivates aluminum, that is, it does not react.
Dilute the water with acid. That's exactly how it is, and not the other way around - pour acid into water as taught in chemistry lessons. If it's the other way around, it might splash.
They mixed it, stirred it a little, put it into a syringe and poured it into a makeshift plasticine bath.
And they left to drink tea with milk for a while.
They arrived - WOW! The thread is clean as... clean in general. There is no hairpin, you can add cognac to tea, although milk is probably rubbish.
…
I also thought it would be like this.
I came, took a look, and there was peace and quiet, and it remained the same, the aluminum of the engine was intact, the stud was also nothing like that.
Maybe I think the acid turned out to be very weak, they say I overdiluted it. I went and took the first bolt I found from the box and threw it into a bottle of diluted acid from which I had just drawn it into a syringe. Twenty minutes later the bolt disappeared, leaving behind a slight cloudiness. And it’s quiet there...
You probably, like me, did not read this sentence very carefully, just above: with the exception of gold, STAINLESS STEEL, platinum group metals, a couple of other metals that are rarely found in the hands of the average person and most importantly aluminum.
Well, the bitch's hairpin turned out to be stainless steel, dear former owner American. In general, I filled everything with a solution of soda - plasticine and the remains of 30% acid in the bottle, for which I received a fountain of reactions and wandered home sad.
Bottom line: Check what you broke off. Indeed, a 30% solution of nitric acid dissolves metal just fine, if it is not aluminum or stainless steel. You won’t have time to blink and there will be no hairpin. And if an ordinary cheap bolt in aluminum or stainless steel breaks off, then this method is very effective and cheap, and most importantly not very labor-intensive. Budget about 1000 maximum including everything (protection, acid, accessories). Time 1-1.5 hours.
That's all. Good luck to all. Take care of yourself.
A broken stud is one of the common defects that a car enthusiast may encounter. Studs are used in many parts of the car. But if you don't have a car, that doesn't mean you'll never get into this situation, because a bolt can also break.
The method for removing debris that I will show, it seems to me, is one of the simplest and most effective. It will work even when the fragment is embedded 2-4 mm deep inside.
Removing the stud piece
So let's get started. First, let's measure the diameter of the pin using its fragment remaining outside. In my case it is 8 mm in diameter.
Take a wooden block and stick 3 layers of masking tape on top of it. Then we make a hole in all three layers with a diameter smaller by one millimeter.
Cut out an arbitrary outline. And we got such a gasket.
We glue it onto the hole with a piece of the pin. This gasket will protect the threads during welding.
Next, you need to take any L-shaped steel corner with a thickness of 2-5 mm. And drill a hole in it 7 mm in diameter.
WITH reverse side Use a large drill to make a hole for the cone.
We place the corner on the hole and secure it with pieces of masking tape so that it does not fall during welding.
The holes must match exactly.
Welding time. It is advisable to use a semi-automatic welding machine. Well, if not, take a regular one, with a thin electrode.
First we fuse a layer onto the fragment.
This is what it looks like after the first time. Let's wait a little.
We fuse another layer for reliability.
Well, now you can try to unscrew the pin.
Everything worked out perfectly. The welding warmed up the fragment and it became easier to unscrew.
This is what it looks like up close.
