Hello all, This is my first post in a long time and my first engine rebuild!! Don't hate me if you ain't me as some might say.

Anyway, here's how it all began. The car has 172k miles on it and has gotten me to and from everywhere in the US without fail, I have been hard on the car, taking it and driving it places meant for vehicles with a much beefier body, regardless it made it this far. Finally my engine had enough and one morning when I went to turn it over I noticed that it sounded like the battery was almost dead. Well a few labored cranks later the engine fired up sounding like you threw like fifty good sized rocks into a dryer and turned it on... Naturally I added oil and decided I needed to get this car back to my house so I could work on it where I sleep. Biggest problem was that I don't have a garage, Only a street. I spent the next couple of days trying to figure out the best options I had available to me, A new car was too expensive, swapping the engine or sub-frame seemed convenient, but I didn't have an engine stand or hoist, Buying a parts car and swapping the parts that I liked from my car to a cobalt that actually runs was really promising to me.

After a thorough-ish analysis of the costs I decided it would be work it to dive into my engine and diagnose the problem, which I originally thought was a broken valve spring or something making noise in the valve train which would have been a quick n easy fix, or maybe the engine jumped a tooth because the chain had stretched and lost tension for a second and now it was a tooth out of time on both ends.

So I began disassembling the engine, starting by draining the oil and coolant. Upon draining the oil I got the pleasure of seeing the oil equivalent of a mixture of ground up pearls. It was horrifying to see the concentration of metal shavings in my oil, I wish I had taken a picture of it. Two oil flushes later and the oil pan looked to have a pound of metal shavings floating within the oil. D:

I then noticed that my normally full coolant reservoir had at some point emptied itself, which instantly signaled that I had blown a head gasket. To find out I took out the cylinder head, removing the Torque to Yield head bolts, camshaft timing sprockets, Throttle body, intake manifold, exhaust manifold, fuel rail, etc. Finally getting everything I needed to get off of the head I pulled it off and almost immediately identified my blowout.



Knowing that I was going to replace my timing and balancing chain systems I went forward and removed the front timing cover and subsequent sprockets, chains, and tensioners and while I was working within the timing cover/front cover I dropped a socket into the oil pan > I knew I couldn't just leave my precious 10 mm socket in the oil pan, so I decided to take it off. This is where we dive into the meat of my first engine build, from this point forward the density of information that I had to learn in order to "correctly" rebuild this engine increased drastically.

So I drop the oil pan and find two hammered, stretched, and sheared pieces of metal just laying in the bottom of the pan, as well as another 1/8" thick layer of metal shavings (might be exaggerating a little bit but the exaggeration matches my surprise on seeing such a large foreign object in my engine oil. I then proceed to look up into the lower block to find this seemingly massive piece of metal sticking out of the side of cylinder two's connecting rod. I quickly learned that the protrusion from the connecting rod was the bearing that used to keep the rod in place and functioning effectively, and was now being pushed out the sides of the connecting rod much like playdough through an extruder.

Faced with the decision to abandon the project right then and there or attempt a lower end rebuild without the ability to machine the crank or block I decided that I had come this far, might as well dive a little deeper into the other three connecting rods and journals and figure out what I am working with. So I pull off the other three connecting rod caps and bearings and find that all but one of the four connecting rod bearings had spun to different degrees. The worst being cylinder two, which had spun the bearing to a point that it got hot enough to melt and weld into the connecting rod and pull out pieces of the lower end of the rod


Having not bought anything more than timing and balancing chain replacement kits and a gasket rebuild kit, I was indeed conflicted on what to do next. Because from the getgo this project had the one goal of get it running without a knock and get it to a dealership before it starts knocking again. I know, its a horrible way to conduct myself, but if the dealerships didn't cut 30% off the new car I bought today as soon as I drove it off the lot I might feel worse about dumping a lemon on them. But now that I was so deep into the engine a new realization hit me, if I can get this car up and running for a short period of time, i.e another 10k miles optimistically, but more realistically like another couple thousand miles, I can use it to get to work and back and make money using it to work, and be able to afford a more reliable option.

Which puts this article where I am right now, and I will post updates as I go along as well as eventually compiling all of the updates into one big informative article that might be able to help someone like me make more educated decisions. I am now sitting at my desk writing this post looking at my pistons in zip lock baggies, with their respective connecting rods laid below them, waiting for me to polish the crank journals and set the piston ring end gaps and begin re-assembly of the engine. I will get into the process I used to set oil clearances for the connecting rods and so on tomorrow. I will also post pictures!!

If anyone has any questions or tips for information to include in future posts or the fully compiled one that I will make from this thread just lemme know!!

 

Idk it it's too late but I would recommend going a different route of either sourcing a cheap used short or long-block. There's a distinct possibility you could invest all this time and money and still end up with a junk engine. 172K is not exactly low mileage and if you are going to rebuild the bottom end it doesn't really make sense to leave the rest worn out or unchecked. There's certain capabilities that machine shops have that I am guessing you don't have access to. Machine shops aren't cheap and will add to your parts cost ending at a number that is far higher than just plopping in a salvage engine.

• The crank should be properly checked, not just polished. I would think the scoring would be bad enough you'd actually need the crank turned down and use oversize bearings. Can't really do this in your driveway so have to pay a machine shop
• You had metal flowing through your oiling system. Your main bearings could be fried as well and crank torn up. Anywhere there was oil flow components could be damaged and will need to be inspected. Not to mention you really need to remove your block to have the whole thing cleaned of metal shavings to have a chance at salvage.
• If you had a bad head gasket you probably need your head checked out and cleaned at the very least. Likely need valve seals replaced. Also valves lapped.
• The mating surface of the block could be bad enough it needs decked. If ignored you could have poor head gasket seal.

The list goes on and on for reasons not to move forward with a driveway rebuild after this level of damage. You should save yourself a whole lot of trouble and junk that engine and either source a complete engine or part out and junk the rest of the car. It's not exactly low mile. To do it right you are going to have to remove the block either way. Your timing and balance/water pump and possibly even gasket can still be returned or sold.

Btw, none of your pictures are showing up either.

 

It is most definitely too late, Believe you me I would not have gone this route if I had any other real option. The good thing is that I have the car in a garage now. There are a million things and one I know I can do to get this car back on the road the "right way" but I have hit a point in the rebuild where I have decided to go no further into the block. I had to draw the line somewhere and this was it. The main thing in my head is this; The car was running before I tore it apart, flakes and all, it just knocked, A LOT xD so the way I see it, once I have re-assembled the engine, IF it runs, it will be running in better condition that it has been for the last X-thousand miles.

That's another thing I should have mentioned, I left out a lot of detail in the original post, which I can and will correct. But I think there is some possibility that I get this car back on the road again just long enough to make enough money to buy another car haha

 

it doesn't seen like yo uhave to much invested into trying to rebuild it yet, but I feel like for a few hundred you could have sourced a running engine, and used a DIY garage, or found a friend with a stand and equipment. If you ask around here, or maybe one of the other social media groups you can probably multiple people who have done swaps in your area or close by. Hell for a couple hundred you can probably buy a another Cobalt, I sold my 07 base model a in 2013 for like $1200.

 

I agree. I would not put any money into that block. Still not too late to cut losses I wouldn't think. You just have to ask yourself that if you throw it back together and it grenades itself, is that something you're OK with?

 

If I end up throwing it back together and it grenades itself I will have to be okay with that. I know that the probability of that happening is pretty darn high. I've committed to the engine and project as a whole, and am in it for the experience if nothing else. I've been without this car for two months now and have a way to make money again, so its taken a good bit of pressure off of this actually working. And having it in a garage now definitely helps in terms of controlling what I can control, its out of the elements.

I know the whole project probably sounds really reaaaallly stupid, I'm aware, but just ride this ride with me and see what happens in the end, if nothing else it'll be surprising

 

I just finished de-glazing and cleaning out each of my cylinders, now I'm ready to set the end gaps on my new ring set!

While doing some googling I found that chamfering oil holes in the crankshaft can increase oil flow to the rod journals, Cylinder 3's journal has worn away the original chamfer on the oil hole and I'm thinking it wouldn't be a bad idea to restore that chamfer and allow more oil to flow and better lubricate the bearing. I have also read that an unchamfered oil hole on a journal will more than likely end up scraping at the bearing surface, inevitably causing the bearing to fail. I am not, however well versed in this area and was looking for suggestions or information if someone has done this before. I will absolutely re-polish any journal that gets chamfered, re-mic and check clearances before the rods go back on the crank.

 

Post up some pictures